From 75e962b1423f7d958b17957ebe971c0c2b262e92 Mon Sep 17 00:00:00 2001
From: erikayasuda <153395705+erikayasuda@users.noreply.github.com>
Date: Mon, 16 Dec 2024 12:57:16 -0500
Subject: [PATCH 01/17] chore: use guess-next-dev instead of
 release-branch-semver [2.18] (#11723)

This PR updates the `version_schema` in the `../pyproject.toml` file for
the 2.18 release branch from `release-branch-semver` to
`guess-next-dev`. This is to ensure that system tests work as intended
with backports to this release branch.

IMPORTANT: This PR needs to be merged before the first backport is
created for 2.18.Otherwise, system tests will not work as expected.

- [x] Reviewer check
---
 pyproject.toml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pyproject.toml b/pyproject.toml
index 9c8ff26d223..95bce61fcd3 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -71,7 +71,7 @@ Homepage = "https://github.com/DataDog/dd-trace-py"
 "Source Code" = "https://github.com/DataDog/dd-trace-py/"
 
 [tool.setuptools_scm]
-version_scheme = "release-branch-semver"  # Must be "release-branch-semver" for now in main, see https://github.com/DataDog/dd-trace-py/issues/8801
+version_scheme = "guess-next-dev"  # Must be "release-branch-semver" for now in main, see https://github.com/DataDog/dd-trace-py/issues/8801
 write_to = "ddtrace/_version.py"
 
 [tool.cython-lint]

From 6bb20368774d661bce8ea9d91dc5e2b5409153e0 Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Wed, 18 Dec 2024 09:37:30 +0100
Subject: [PATCH 02/17] fix(iast): check context is enable in request and
 builtins patched funcions [backport 2.18] (#11756)

Backport a4f0e380a459542795f2d881895f18765211893b from #11752 to 2.18.

This fix resolves an issue where AppSec was using a patched request and
builtins functions, creating telemetry errors.
## Checklist
- [x] PR author has checked that all the criteria below are met
- The PR description includes an overview of the change
- The PR description articulates the motivation for the change
- The change includes tests OR the PR description describes a testing
strategy
- The PR description notes risks associated with the change, if any
- Newly-added code is easy to change
- The change follows the [library release note
guidelines](https://ddtrace.readthedocs.io/en/stable/releasenotes.html)
- The change includes or references documentation updates if necessary
- Backport labels are set (if
[applicable](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting))

## Reviewer Checklist
- [x] Reviewer has checked that all the criteria below are met
- Title is accurate
- All changes are related to the pull request's stated goal
- Avoids breaking
[API](https://ddtrace.readthedocs.io/en/stable/versioning.html#interfaces)
changes
- Testing strategy adequately addresses listed risks
- Newly-added code is easy to change
- Release note makes sense to a user of the library
- If necessary, author has acknowledged and discussed the performance
implications of this PR as reported in the benchmarks PR comment
- Backport labels are set in a manner that is consistent with the
[release branch maintenance
policy](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting)

Co-authored-by: Alberto Vara <alberto.vara@datadoghq.com>
---
 ddtrace/appsec/_common_module_patches.py         | 16 ++++++++++++----
 ...ast-propagation-error-2-ba4a998133269a7c.yaml |  5 +++++
 2 files changed, 17 insertions(+), 4 deletions(-)
 create mode 100644 releasenotes/notes/iast-fix-iast-propagation-error-2-ba4a998133269a7c.yaml

diff --git a/ddtrace/appsec/_common_module_patches.py b/ddtrace/appsec/_common_module_patches.py
index a5ab2d1533d..e7ce12d13e9 100644
--- a/ddtrace/appsec/_common_module_patches.py
+++ b/ddtrace/appsec/_common_module_patches.py
@@ -60,8 +60,10 @@ def wrapped_read_F3E51D71B4EC16EF(original_read_callable, instance, args, kwargs
     """
     wrapper for _io.BytesIO and _io.StringIO read function
     """
+    from ddtrace.appsec._iast._iast_request_context import is_iast_request_enabled
+
     result = original_read_callable(*args, **kwargs)
-    if asm_config._iast_enabled:
+    if asm_config._iast_enabled and is_iast_request_enabled():
         from ddtrace.appsec._iast._taint_tracking import OriginType
         from ddtrace.appsec._iast._taint_tracking import Source
         from ddtrace.appsec._iast._taint_tracking import get_tainted_ranges
@@ -87,7 +89,9 @@ def wrapped_open_CFDDB7ABBA9081B6(original_open_callable, instance, args, kwargs
     """
     wrapper for open file function
     """
-    if asm_config._iast_enabled:
+    from ddtrace.appsec._iast._iast_request_context import is_iast_request_enabled
+
+    if asm_config._iast_enabled and is_iast_request_enabled():
         try:
             from ddtrace.appsec._iast.taint_sinks.path_traversal import check_and_report_path_traversal
 
@@ -176,7 +180,9 @@ def wrapped_request_D8CB81E472AF98A2(original_request_callable, instance, args,
     wrapper for third party requests.request function
     https://requests.readthedocs.io
     """
-    if asm_config._iast_enabled:
+    from ddtrace.appsec._iast._iast_request_context import is_iast_request_enabled
+
+    if asm_config._iast_enabled and is_iast_request_enabled():
         from ddtrace.appsec._iast.taint_sinks.ssrf import _iast_report_ssrf
 
         _iast_report_ssrf(original_request_callable, *args, **kwargs)
@@ -216,7 +222,9 @@ def wrapped_system_5542593D237084A7(original_command_callable, instance, args, k
     """
     command = args[0] if args else kwargs.get("command", None)
     if command is not None:
-        if asm_config._iast_enabled:
+        from ddtrace.appsec._iast._iast_request_context import is_iast_request_enabled
+
+        if asm_config._iast_enabled and is_iast_request_enabled():
             from ddtrace.appsec._iast.taint_sinks.command_injection import _iast_report_cmdi
 
             _iast_report_cmdi(command)
diff --git a/releasenotes/notes/iast-fix-iast-propagation-error-2-ba4a998133269a7c.yaml b/releasenotes/notes/iast-fix-iast-propagation-error-2-ba4a998133269a7c.yaml
new file mode 100644
index 00000000000..4918edb17a7
--- /dev/null
+++ b/releasenotes/notes/iast-fix-iast-propagation-error-2-ba4a998133269a7c.yaml
@@ -0,0 +1,5 @@
+---
+fixes:
+  - |
+    ASM: This fix resolves an issue where AppSec was using a patched request and builtins functions, 
+    creating telemetry errors.
\ No newline at end of file

From 9924f37ad8536edd2466f3874bc691eb5e64719a Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Wed, 18 Dec 2024 20:20:28 +0000
Subject: [PATCH 03/17] chore(ci): upgrade python for build action [backport
 2.18] (#11782)

Co-authored-by: Christophe Papazian <114495376+christophe-papazian@users.noreply.github.com>
---
 .github/workflows/build_deploy.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/build_deploy.yml b/.github/workflows/build_deploy.yml
index 77d52c757f5..df5184f83e5 100644
--- a/.github/workflows/build_deploy.yml
+++ b/.github/workflows/build_deploy.yml
@@ -40,7 +40,7 @@ jobs:
       - uses: actions/setup-python@v5
         name: Install Python
         with:
-          python-version: '3.7'
+          python-version: '3.12'
       - name: Build sdist
         run: |
           pip install "setuptools_scm[toml]>=4" "cython" "cmake>=3.24.2,<3.28" "setuptools-rust"

From e1b10df2aaddf1314c64aa73d1c810d698f7613f Mon Sep 17 00:00:00 2001
From: ZStriker19 <zach.groves@datadoghq.com>
Date: Thu, 19 Dec 2024 18:29:38 -0500
Subject: [PATCH 04/17] add extract behavior feat

---
 ddtrace/internal/constants.py                 |   4 +
 ddtrace/propagation/http.py                   |  61 +++--
 ddtrace/settings/config.py                    |   8 +
 ...ion_behavior_extract-3d16765cfd07485b.yaml |   7 +
 tests/telemetry/test_writer.py                |   4 +-
 tests/tracer/test_propagation.py              | 224 +++++++++++++++++-
 6 files changed, 282 insertions(+), 26 deletions(-)
 create mode 100644 releasenotes/notes/propagation_behavior_extract-3d16765cfd07485b.yaml

diff --git a/ddtrace/internal/constants.py b/ddtrace/internal/constants.py
index 4efdc754ef3..c4255035c41 100644
--- a/ddtrace/internal/constants.py
+++ b/ddtrace/internal/constants.py
@@ -19,6 +19,10 @@
     _PROPAGATION_STYLE_NONE,
     _PROPAGATION_STYLE_BAGGAGE,
 )
+_PROPAGATION_BEHAVIOR_CONTINUE = "continue"
+_PROPAGATION_BEHAVIOR_IGNORE = "ignore"
+_PROPAGATION_BEHAVIOR_RESTART = "restart"
+_PROPAGATION_BEHAVIOR_DEFAULT = _PROPAGATION_BEHAVIOR_CONTINUE
 W3C_TRACESTATE_KEY = "tracestate"
 W3C_TRACEPARENT_KEY = "traceparent"
 W3C_TRACESTATE_PARENT_ID_KEY = "p"
diff --git a/ddtrace/propagation/http.py b/ddtrace/propagation/http.py
index a1664664ace..6d7cd8325ab 100644
--- a/ddtrace/propagation/http.py
+++ b/ddtrace/propagation/http.py
@@ -40,6 +40,8 @@
 from ..internal._tagset import decode_tagset_string
 from ..internal._tagset import encode_tagset_values
 from ..internal.compat import ensure_text
+from ..internal.constants import _PROPAGATION_BEHAVIOR_IGNORE
+from ..internal.constants import _PROPAGATION_BEHAVIOR_RESTART
 from ..internal.constants import _PROPAGATION_STYLE_BAGGAGE
 from ..internal.constants import _PROPAGATION_STYLE_NONE
 from ..internal.constants import _PROPAGATION_STYLE_W3C_TRACECONTEXT
@@ -973,12 +975,12 @@ class HTTPPropagator(object):
     """
 
     @staticmethod
-    def _extract_configured_contexts_avail(normalized_headers):
+    def _extract_configured_contexts_avail(normalized_headers: Dict[str, str]) -> Tuple[List[Context], List[str]]:
         contexts = []
         styles_w_ctx = []
         for prop_style in config._propagation_style_extract:
             propagator = _PROP_STYLES[prop_style]
-            context = propagator._extract(normalized_headers)
+            context = propagator._extract(normalized_headers)  # type: ignore
             # baggage is handled separately
             if prop_style == _PROPAGATION_STYLE_BAGGAGE:
                 continue
@@ -987,6 +989,24 @@ def _extract_configured_contexts_avail(normalized_headers):
                 styles_w_ctx.append(prop_style)
         return contexts, styles_w_ctx
 
+    @staticmethod
+    def _context_to_span_link(context: Context, style: str, reason: str) -> Optional[SpanLink]:
+        # encoding expects at least trace_id and span_id
+        if context.span_id and context.trace_id:
+            return SpanLink(
+                context.trace_id,
+                context.span_id,
+                flags=1 if context.sampling_priority and context.sampling_priority > 0 else 0,
+                tracestate=(
+                    context._meta.get(W3C_TRACESTATE_KEY, "") if style == _PROPAGATION_STYLE_W3C_TRACECONTEXT else None
+                ),
+                attributes={
+                    "reason": reason,
+                    "context_headers": style,
+                },
+            )
+        return None
+
     @staticmethod
     def _resolve_contexts(contexts, styles_w_ctx, normalized_headers):
         primary_context = contexts[0]
@@ -995,23 +1015,14 @@ def _resolve_contexts(contexts, styles_w_ctx, normalized_headers):
         for context in contexts[1:]:
             style_w_ctx = styles_w_ctx[contexts.index(context)]
             # encoding expects at least trace_id and span_id
-            if context.span_id and context.trace_id and context.trace_id != primary_context.trace_id:
-                links.append(
-                    SpanLink(
-                        context.trace_id,
-                        context.span_id,
-                        flags=1 if context.sampling_priority and context.sampling_priority > 0 else 0,
-                        tracestate=(
-                            context._meta.get(W3C_TRACESTATE_KEY, "")
-                            if style_w_ctx == _PROPAGATION_STYLE_W3C_TRACECONTEXT
-                            else None
-                        ),
-                        attributes={
-                            "reason": "terminated_context",
-                            "context_headers": style_w_ctx,
-                        },
-                    )
+            if context.trace_id and context.trace_id != primary_context.trace_id:
+                link = HTTPPropagator._context_to_span_link(
+                    context,
+                    style_w_ctx,
+                    "terminated_context",
                 )
+                if link:
+                    links.append(link)
             # if trace_id matches and the propagation style is tracecontext
             # add the tracestate to the primary context
             elif style_w_ctx == _PROPAGATION_STYLE_W3C_TRACECONTEXT:
@@ -1129,17 +1140,19 @@ def my_controller(url, headers):
         :param dict headers: HTTP headers to extract tracing attributes.
         :return: New `Context` with propagated attributes.
         """
-        if not headers:
-            return Context()
+        context = Context()
+        if not headers or config._propagation_behavior_extract == _PROPAGATION_BEHAVIOR_IGNORE:
+            return context
         try:
+            style = ""
             normalized_headers = {name.lower(): v for name, v in headers.items()}
-            context = Context()
             # tracer configured to extract first only
             if config._propagation_extract_first:
                 # loop through the extract propagation styles specified in order, return whatever context we get first
                 for prop_style in config._propagation_style_extract:
                     propagator = _PROP_STYLES[prop_style]
                     context = propagator._extract(normalized_headers)
+                    style = prop_style
                     if config.propagation_http_baggage_enabled is True:
                         _attach_baggage_to_context(normalized_headers, context)
                     break
@@ -1147,6 +1160,9 @@ def my_controller(url, headers):
             # loop through all extract propagation styles
             else:
                 contexts, styles_w_ctx = HTTPPropagator._extract_configured_contexts_avail(normalized_headers)
+                # check that styles_w_ctx is not empty
+                if styles_w_ctx:
+                    style = styles_w_ctx[0]
 
                 if contexts:
                     context = HTTPPropagator._resolve_contexts(contexts, styles_w_ctx, normalized_headers)
@@ -1161,6 +1177,9 @@ def my_controller(url, headers):
                         context._baggage = baggage_context._baggage
                     else:
                         context = baggage_context
+            if config._propagation_behavior_extract == _PROPAGATION_BEHAVIOR_RESTART:
+                link = HTTPPropagator._context_to_span_link(context, style, "propagation_behavior_extract")
+                context = Context(baggage=context.get_all_baggage_items(), span_links=[link] if link else [])
 
             return context
 
diff --git a/ddtrace/settings/config.py b/ddtrace/settings/config.py
index 65baf99ccb3..1f1f3730e3c 100644
--- a/ddtrace/settings/config.py
+++ b/ddtrace/settings/config.py
@@ -20,6 +20,7 @@
 from ddtrace.vendor.debtcollector import deprecate
 
 from ..internal import gitmetadata
+from ..internal.constants import _PROPAGATION_BEHAVIOR_DEFAULT
 from ..internal.constants import _PROPAGATION_STYLE_DEFAULT
 from ..internal.constants import DEFAULT_BUFFER_SIZE
 from ..internal.constants import DEFAULT_MAX_PAYLOAD_SIZE
@@ -540,6 +541,10 @@ def __init__(self):
 
         self._propagation_extract_first = _get_config("DD_TRACE_PROPAGATION_EXTRACT_FIRST", False, asbool)
 
+        self._propagation_behavior_extract = _get_config(
+            ["DD_TRACE_PROPAGATION_BEHAVIOR_EXTRACT"], _PROPAGATION_BEHAVIOR_DEFAULT, self._lower
+        )
+
         # Datadog tracer tags propagation
         x_datadog_tags_max_length = _get_config("DD_TRACE_X_DATADOG_TAGS_MAX_LENGTH", 512, int)
         if x_datadog_tags_max_length < 0:
@@ -978,3 +983,6 @@ def convert_rc_trace_sampling_rules(self, rc_rules: List[Dict[str, Any]]) -> Opt
             return json.dumps(rc_rules)
         else:
             return None
+
+    def _lower(self, value):
+        return value.lower()
diff --git a/releasenotes/notes/propagation_behavior_extract-3d16765cfd07485b.yaml b/releasenotes/notes/propagation_behavior_extract-3d16765cfd07485b.yaml
new file mode 100644
index 00000000000..8e34092a6bb
--- /dev/null
+++ b/releasenotes/notes/propagation_behavior_extract-3d16765cfd07485b.yaml
@@ -0,0 +1,7 @@
+---
+features:
+  - |
+    propagation: This introduces the environment variable ``DD_TRACE_PROPAGATION_BEHAVIOR_EXTRACT`` 
+    to control the behavior of the extraction of distributed tracing headers. The values, ``continue`` (default),
+    ``ignore``, and ``restart``, are supported. The default value is ``continue`` which should have no change from the current behavior of always propagating valid headers.
+    With ``ignore`` ignoring all incoming headers and with ``restart`` turning incoming headers into a span links and propagating baggage items.
diff --git a/tests/telemetry/test_writer.py b/tests/telemetry/test_writer.py
index 7718710ff60..e1a34f406a0 100644
--- a/tests/telemetry/test_writer.py
+++ b/tests/telemetry/test_writer.py
@@ -268,7 +268,8 @@ def test_app_started_event_configuration_override(test_agent_session, run_python
     env["DD_SPAN_SAMPLING_RULES_FILE"] = str(file)
     env["DD_TRACE_PARTIAL_FLUSH_ENABLED"] = "false"
     env["DD_TRACE_PARTIAL_FLUSH_MIN_SPANS"] = "3"
-    env["DD_SITE"] = "datadoghq.com"
+    env["DD_TRACE_PROPAGATION_BEHAVIOR_EXTRACT"] = "restart"
+
     # By default telemetry collection is enabled after 10 seconds, so we either need to
     # to sleep for 10 seconds or manually call _app_started() to generate the app started event.
     # This delay allows us to collect start up errors and dynamic configurations
@@ -444,6 +445,7 @@ def test_app_started_event_configuration_override(test_agent_session, run_python
         {"name": "DD_TRACE_OTEL_ENABLED", "origin": "env_var", "value": True},
         {"name": "DD_TRACE_PARTIAL_FLUSH_ENABLED", "origin": "env_var", "value": False},
         {"name": "DD_TRACE_PARTIAL_FLUSH_MIN_SPANS", "origin": "env_var", "value": 3},
+        {"name": "DD_TRACE_PROPAGATION_BEHAVIOR_EXTRACT", "origin": "env_var", "value": "restart"},
         {"name": "DD_TRACE_PROPAGATION_EXTRACT_FIRST", "origin": "default", "value": False},
         {"name": "DD_TRACE_PROPAGATION_HTTP_BAGGAGE_ENABLED", "origin": "default", "value": False},
         {"name": "DD_TRACE_PROPAGATION_STYLE_EXTRACT", "origin": "env_var", "value": "tracecontext"},
diff --git a/tests/tracer/test_propagation.py b/tests/tracer/test_propagation.py
index 2e1a299c4d4..7c29ce9c473 100644
--- a/tests/tracer/test_propagation.py
+++ b/tests/tracer/test_propagation.py
@@ -15,6 +15,8 @@
 from ddtrace.constants import AUTO_REJECT
 from ddtrace.constants import USER_KEEP
 from ddtrace.constants import USER_REJECT
+from ddtrace.internal.constants import _PROPAGATION_BEHAVIOR_IGNORE
+from ddtrace.internal.constants import _PROPAGATION_BEHAVIOR_RESTART
 from ddtrace.internal.constants import _PROPAGATION_STYLE_BAGGAGE
 from ddtrace.internal.constants import _PROPAGATION_STYLE_NONE
 from ddtrace.internal.constants import _PROPAGATION_STYLE_W3C_TRACECONTEXT
@@ -1500,6 +1502,9 @@ def test_extract_tracecontext(headers, expected_context):
     HTTP_HEADER_PARENT_ID: "parent_id",
     HTTP_HEADER_SAMPLING_PRIORITY: "sample",
 }
+
+DATADOG_BAGGAGE_HEADERS_VALID = {**DATADOG_HEADERS_VALID, "baggage": "key1=val1,key2=val2"}
+
 B3_HEADERS_VALID = {
     _HTTP_HEADER_B3_TRACE_ID: "80f198ee56343ba864fe8b2a57d3eff7",
     _HTTP_HEADER_B3_SPAN_ID: "a2fb4a1d1a96d312",
@@ -1553,6 +1558,7 @@ def test_extract_tracecontext(headers, expected_context):
     (
         "valid_datadog_default",
         None,
+        None,
         DATADOG_HEADERS_VALID,
         {
             "trace_id": 13088165645273925489,
@@ -1565,6 +1571,7 @@ def test_extract_tracecontext(headers, expected_context):
     (
         "valid_datadog_default_wsgi",
         None,
+        None,
         {get_wsgi_header(name): value for name, value in DATADOG_HEADERS_VALID.items()},
         {
             "trace_id": 13088165645273925489,
@@ -1577,6 +1584,7 @@ def test_extract_tracecontext(headers, expected_context):
     (
         "valid_datadog_no_priority",
         None,
+        None,
         DATADOG_HEADERS_VALID_NO_PRIORITY,
         {
             "trace_id": 13088165645273925489,
@@ -1589,12 +1597,14 @@ def test_extract_tracecontext(headers, expected_context):
     (
         "invalid_datadog",
         [PROPAGATION_STYLE_DATADOG],
+        None,
         DATADOG_HEADERS_INVALID,
         CONTEXT_EMPTY,
     ),
     (
         "valid_datadog_explicit_style",
         [PROPAGATION_STYLE_DATADOG],
+        None,
         DATADOG_HEADERS_VALID,
         {
             "trace_id": 13088165645273925489,
@@ -1607,6 +1617,7 @@ def test_extract_tracecontext(headers, expected_context):
     (
         "invalid_datadog_negative_trace_id",
         [PROPAGATION_STYLE_DATADOG],
+        None,
         {
             HTTP_HEADER_TRACE_ID: "-1",
             HTTP_HEADER_PARENT_ID: "5678",
@@ -1618,6 +1629,7 @@ def test_extract_tracecontext(headers, expected_context):
     (
         "valid_datadog_explicit_style_wsgi",
         [PROPAGATION_STYLE_DATADOG],
+        None,
         {get_wsgi_header(name): value for name, value in DATADOG_HEADERS_VALID.items()},
         {
             "trace_id": 13088165645273925489,
@@ -1630,6 +1642,7 @@ def test_extract_tracecontext(headers, expected_context):
     (
         "valid_datadog_all_styles",
         [PROPAGATION_STYLE_DATADOG, PROPAGATION_STYLE_B3_MULTI, PROPAGATION_STYLE_B3_SINGLE],
+        None,
         DATADOG_HEADERS_VALID,
         {
             "trace_id": 13088165645273925489,
@@ -1642,13 +1655,29 @@ def test_extract_tracecontext(headers, expected_context):
     (
         "valid_datadog_no_datadog_style",
         [PROPAGATION_STYLE_B3_MULTI],
+        None,
         DATADOG_HEADERS_VALID,
         CONTEXT_EMPTY,
     ),
+    (
+        "valid_datadog_and_baggage_default",
+        None,
+        None,
+        DATADOG_BAGGAGE_HEADERS_VALID,
+        {
+            "trace_id": 13088165645273925489,
+            "span_id": 5678,
+            "sampling_priority": 1,
+            "dd_origin": "synthetics",
+            "meta": {"_dd.p.dm": "-3"},
+            "baggage": {"key1": "val1", "key2": "val2"},
+        },
+    ),
     # B3 headers
     (
         "valid_b3_simple",
         [PROPAGATION_STYLE_B3_MULTI],
+        None,
         B3_HEADERS_VALID,
         {
             "trace_id": TRACE_ID,
@@ -1660,6 +1689,7 @@ def test_extract_tracecontext(headers, expected_context):
     (
         "valid_b3_wsgi",
         [PROPAGATION_STYLE_B3_MULTI],
+        None,
         {get_wsgi_header(name): value for name, value in B3_HEADERS_VALID.items()},
         {
             "trace_id": TRACE_ID,
@@ -1671,6 +1701,7 @@ def test_extract_tracecontext(headers, expected_context):
     (
         "valid_b3_flags",
         [PROPAGATION_STYLE_B3_MULTI],
+        None,
         {
             _HTTP_HEADER_B3_TRACE_ID: B3_HEADERS_VALID[_HTTP_HEADER_B3_TRACE_ID],
             _HTTP_HEADER_B3_SPAN_ID: B3_HEADERS_VALID[_HTTP_HEADER_B3_SPAN_ID],
@@ -1686,6 +1717,7 @@ def test_extract_tracecontext(headers, expected_context):
     (
         "valid_b3_with_parent_id",
         [PROPAGATION_STYLE_B3_MULTI],
+        None,
         {
             _HTTP_HEADER_B3_TRACE_ID: B3_HEADERS_VALID[_HTTP_HEADER_B3_TRACE_ID],
             _HTTP_HEADER_B3_SPAN_ID: B3_HEADERS_VALID[_HTTP_HEADER_B3_SPAN_ID],
@@ -1702,6 +1734,7 @@ def test_extract_tracecontext(headers, expected_context):
     (
         "valid_b3_only_trace_and_span_id",
         [PROPAGATION_STYLE_B3_MULTI],
+        None,
         {
             _HTTP_HEADER_B3_TRACE_ID: B3_HEADERS_VALID[_HTTP_HEADER_B3_TRACE_ID],
             _HTTP_HEADER_B3_SPAN_ID: B3_HEADERS_VALID[_HTTP_HEADER_B3_SPAN_ID],
@@ -1716,6 +1749,7 @@ def test_extract_tracecontext(headers, expected_context):
     (
         "valid_b3_only_trace_id",
         [PROPAGATION_STYLE_B3_MULTI],
+        None,
         {
             _HTTP_HEADER_B3_TRACE_ID: B3_HEADERS_VALID[_HTTP_HEADER_B3_TRACE_ID],
         },
@@ -1729,24 +1763,28 @@ def test_extract_tracecontext(headers, expected_context):
     (
         "invalid_b3",
         [PROPAGATION_STYLE_B3_MULTI],
+        None,
         B3_HEADERS_INVALID,
         CONTEXT_EMPTY,
     ),
     (
         "valid_b3_default_style",
         None,
+        None,
         B3_HEADERS_VALID,
         CONTEXT_EMPTY,
     ),
     (
         "valid_b3_no_b3_style",
         [PROPAGATION_STYLE_B3_SINGLE],
+        None,
         B3_HEADERS_VALID,
         CONTEXT_EMPTY,
     ),
     (
         "valid_b3_all_styles",
         [PROPAGATION_STYLE_DATADOG, PROPAGATION_STYLE_B3_MULTI, PROPAGATION_STYLE_B3_SINGLE],
+        None,
         B3_HEADERS_VALID,
         {
             "trace_id": TRACE_ID,
@@ -1759,6 +1797,7 @@ def test_extract_tracecontext(headers, expected_context):
     (
         "valid_b3_single_header_simple",
         [PROPAGATION_STYLE_B3_SINGLE],
+        None,
         B3_SINGLE_HEADERS_VALID,
         {
             "trace_id": TRACE_ID,
@@ -1770,6 +1809,7 @@ def test_extract_tracecontext(headers, expected_context):
     (
         "valid_b3_single_header_simple",
         [PROPAGATION_STYLE_B3_SINGLE],
+        None,
         {
             get_wsgi_header(_HTTP_HEADER_B3_SINGLE): B3_SINGLE_HEADERS_VALID[_HTTP_HEADER_B3_SINGLE],
         },
@@ -1783,6 +1823,7 @@ def test_extract_tracecontext(headers, expected_context):
     (
         "valid_b3_single_header_simple",
         [PROPAGATION_STYLE_B3_SINGLE],
+        None,
         {
             get_wsgi_header(_HTTP_HEADER_B3_SINGLE): B3_SINGLE_HEADERS_VALID[_HTTP_HEADER_B3_SINGLE],
         },
@@ -1796,6 +1837,7 @@ def test_extract_tracecontext(headers, expected_context):
     (
         "valid_b3_single_header_only_sampled",
         [PROPAGATION_STYLE_B3_SINGLE],
+        None,
         {
             _HTTP_HEADER_B3_SINGLE: "1",
         },
@@ -1809,6 +1851,7 @@ def test_extract_tracecontext(headers, expected_context):
     (
         "valid_b3_single_header_only_trace_and_span_id",
         [PROPAGATION_STYLE_B3_SINGLE],
+        None,
         {
             _HTTP_HEADER_B3_SINGLE: "80f198ee56343ba864fe8b2a57d3eff7-e457b5a2e4d86bd1",
         },
@@ -1822,12 +1865,14 @@ def test_extract_tracecontext(headers, expected_context):
     (
         "invalid_b3_single_header",
         [PROPAGATION_STYLE_B3_SINGLE],
+        None,
         B3_SINGLE_HEADERS_INVALID,
         CONTEXT_EMPTY,
     ),
     (
         "valid_b3_single_header_all_styles",
         [PROPAGATION_STYLE_DATADOG, PROPAGATION_STYLE_B3_MULTI, PROPAGATION_STYLE_B3_SINGLE],
+        None,
         B3_SINGLE_HEADERS_VALID,
         {
             "trace_id": TRACE_ID,
@@ -1839,6 +1884,7 @@ def test_extract_tracecontext(headers, expected_context):
     (
         "valid_b3_single_header_extra_data",
         [PROPAGATION_STYLE_B3_SINGLE],
+        None,
         {_HTTP_HEADER_B3_SINGLE: B3_SINGLE_HEADERS_VALID[_HTTP_HEADER_B3_SINGLE] + "-05e3ac9a4f6e3b90-extra-data-here"},
         {
             "trace_id": TRACE_ID,
@@ -1850,12 +1896,14 @@ def test_extract_tracecontext(headers, expected_context):
     (
         "valid_b3_single_header_default_style",
         None,
+        None,
         B3_SINGLE_HEADERS_VALID,
         CONTEXT_EMPTY,
     ),
     (
         "valid_b3_single_header_no_b3_single_header_style",
         [PROPAGATION_STYLE_B3_MULTI],
+        None,
         B3_SINGLE_HEADERS_VALID,
         CONTEXT_EMPTY,
     ),
@@ -1863,6 +1911,7 @@ def test_extract_tracecontext(headers, expected_context):
     (
         "valid_all_headers_default_style",
         None,
+        None,
         ALL_HEADERS,
         {
             "trace_id": 13088165645273925489,
@@ -1891,6 +1940,7 @@ def test_extract_tracecontext(headers, expected_context):
             PROPAGATION_STYLE_B3_SINGLE,
             _PROPAGATION_STYLE_W3C_TRACECONTEXT,
         ],
+        None,
         ALL_HEADERS,
         {
             "trace_id": 13088165645273925489,
@@ -1931,6 +1981,7 @@ def test_extract_tracecontext(headers, expected_context):
             PROPAGATION_STYLE_B3_SINGLE,
             _PROPAGATION_STYLE_W3C_TRACECONTEXT,
         ],
+        None,
         {get_wsgi_header(name): value for name, value in ALL_HEADERS.items()},
         {
             "trace_id": 13088165645273925489,
@@ -1966,6 +2017,7 @@ def test_extract_tracecontext(headers, expected_context):
     (
         "valid_all_headers_datadog_style",
         [PROPAGATION_STYLE_DATADOG],
+        None,
         ALL_HEADERS,
         {
             "trace_id": 13088165645273925489,
@@ -1978,6 +2030,7 @@ def test_extract_tracecontext(headers, expected_context):
     (
         "valid_all_headers_datadog_style_wsgi",
         [PROPAGATION_STYLE_DATADOG],
+        None,
         {get_wsgi_header(name): value for name, value in ALL_HEADERS.items()},
         {
             "trace_id": 13088165645273925489,
@@ -1990,6 +2043,7 @@ def test_extract_tracecontext(headers, expected_context):
     (
         "valid_all_headers_b3_style",
         [PROPAGATION_STYLE_B3_MULTI],
+        None,
         ALL_HEADERS,
         {
             "trace_id": TRACE_ID,
@@ -2001,6 +2055,7 @@ def test_extract_tracecontext(headers, expected_context):
     (
         "valid_all_headers_b3_style_wsgi",
         [PROPAGATION_STYLE_B3_MULTI],
+        None,
         {get_wsgi_header(name): value for name, value in ALL_HEADERS.items()},
         {
             "trace_id": TRACE_ID,
@@ -2012,6 +2067,7 @@ def test_extract_tracecontext(headers, expected_context):
     (
         "valid_all_headers_both_b3_styles",
         [PROPAGATION_STYLE_B3_MULTI, PROPAGATION_STYLE_B3_SINGLE],
+        None,
         ALL_HEADERS,
         {
             "trace_id": TRACE_ID,
@@ -2023,6 +2079,7 @@ def test_extract_tracecontext(headers, expected_context):
     (
         "valid_all_headers_b3_single_style",
         [PROPAGATION_STYLE_B3_SINGLE],
+        None,
         ALL_HEADERS,
         {
             "trace_id": TRACE_ID,
@@ -2035,6 +2092,7 @@ def test_extract_tracecontext(headers, expected_context):
         # name, styles, headers, expected_context,
         "none_style",
         [_PROPAGATION_STYLE_NONE],
+        None,
         ALL_HEADERS,
         {
             "trace_id": None,
@@ -2047,6 +2105,7 @@ def test_extract_tracecontext(headers, expected_context):
         # name, styles, headers, expected_context,
         "none_and_other_prop_style_still_extracts",
         [PROPAGATION_STYLE_DATADOG, _PROPAGATION_STYLE_NONE],
+        None,
         ALL_HEADERS,
         {
             "trace_id": 13088165645273925489,
@@ -2060,6 +2119,7 @@ def test_extract_tracecontext(headers, expected_context):
     (
         "order_matters_B3_SINGLE_HEADER_first",
         [PROPAGATION_STYLE_B3_SINGLE, PROPAGATION_STYLE_B3_MULTI, PROPAGATION_STYLE_DATADOG],
+        None,
         B3_SINGLE_HEADERS_VALID,
         {
             "trace_id": TRACE_ID,
@@ -2076,6 +2136,7 @@ def test_extract_tracecontext(headers, expected_context):
             PROPAGATION_STYLE_DATADOG,
             _PROPAGATION_STYLE_W3C_TRACECONTEXT,
         ],
+        None,
         B3_HEADERS_VALID,
         {
             "trace_id": TRACE_ID,
@@ -2087,6 +2148,7 @@ def test_extract_tracecontext(headers, expected_context):
     (
         "order_matters_B3_second_no_Datadog_headers",
         [PROPAGATION_STYLE_DATADOG, PROPAGATION_STYLE_B3_MULTI],
+        None,
         B3_HEADERS_VALID,
         {
             "trace_id": TRACE_ID,
@@ -2098,6 +2160,7 @@ def test_extract_tracecontext(headers, expected_context):
     (
         "valid_all_headers_b3_single_style_wsgi",
         [PROPAGATION_STYLE_B3_SINGLE],
+        None,
         {get_wsgi_header(name): value for name, value in ALL_HEADERS.items()},
         {
             "trace_id": TRACE_ID,
@@ -2116,6 +2179,7 @@ def test_extract_tracecontext(headers, expected_context):
             _PROPAGATION_STYLE_W3C_TRACECONTEXT,
             PROPAGATION_STYLE_B3_SINGLE,
         ],
+        None,
         DATADOG_TRACECONTEXT_MATCHING_TRACE_ID_HEADERS,
         {
             "trace_id": _get_64_lowest_order_bits_as_int(TRACE_ID),
@@ -2133,6 +2197,7 @@ def test_extract_tracecontext(headers, expected_context):
     (
         "no_additional_tracestate_support_when_present_but_trace_ids_do_not_match",
         [PROPAGATION_STYLE_DATADOG, _PROPAGATION_STYLE_W3C_TRACECONTEXT],
+        None,
         {**DATADOG_HEADERS_VALID, **TRACECONTEXT_HEADERS_VALID_RUM_NO_SAMPLING_DECISION},
         {
             "trace_id": 13088165645273925489,
@@ -2154,18 +2219,21 @@ def test_extract_tracecontext(headers, expected_context):
     (
         "valid_all_headers_no_style",
         [],
+        None,
         ALL_HEADERS,
         CONTEXT_EMPTY,
     ),
     (
         "valid_all_headers_no_style_wsgi",
         [],
+        None,
         {get_wsgi_header(name): value for name, value in ALL_HEADERS.items()},
         CONTEXT_EMPTY,
     ),
     (
         "datadog_tracecontext_conflicting_span_ids",
         [PROPAGATION_STYLE_DATADOG, _PROPAGATION_STYLE_W3C_TRACECONTEXT],
+        None,
         {
             HTTP_HEADER_TRACE_ID: "9291375655657946024",
             HTTP_HEADER_PARENT_ID: "15",
@@ -2178,6 +2246,142 @@ def test_extract_tracecontext(headers, expected_context):
             "meta": {"_dd.p.dm": "-3", LAST_DD_PARENT_ID_KEY: "000000000000000f"},
         },
     ),
+    (
+        "valid_datadog_default_w_restart_behavior",
+        None,
+        _PROPAGATION_BEHAVIOR_RESTART,
+        DATADOG_HEADERS_VALID,
+        {
+            "trace_id": None,
+            "span_id": None,
+            "sampling_priority": None,
+            "dd_origin": None,
+            "span_links": [
+                SpanLink(
+                    trace_id=13088165645273925489,
+                    span_id=5678,
+                    tracestate=None,
+                    flags=1,
+                    attributes={"reason": "propagation_behavior_extract", "context_headers": "datadog"},
+                )
+            ],
+        },
+    ),
+    (
+        "valid_datadog_and_baggage_default_w_restart_behavior",
+        None,
+        _PROPAGATION_BEHAVIOR_RESTART,
+        DATADOG_BAGGAGE_HEADERS_VALID,
+        {
+            "trace_id": None,
+            "span_id": None,
+            "sampling_priority": None,
+            "dd_origin": None,
+            "baggage": {"key1": "val1", "key2": "val2"},
+            "span_links": [
+                SpanLink(
+                    trace_id=13088165645273925489,
+                    span_id=5678,
+                    tracestate=None,
+                    flags=1,
+                    attributes={"reason": "propagation_behavior_extract", "context_headers": "datadog"},
+                )
+            ],
+        },
+    ),
+    (
+        "valid_datadog_default_w_ignore_behavior",
+        None,
+        _PROPAGATION_BEHAVIOR_IGNORE,
+        DATADOG_HEADERS_VALID,
+        CONTEXT_EMPTY,
+    ),
+    # All valid headers
+    (
+        "valid_all_headers_default_style_w_restart_behavior",
+        None,
+        _PROPAGATION_BEHAVIOR_RESTART,
+        ALL_HEADERS,
+        {
+            "trace_id": None,
+            "span_id": None,
+            "sampling_priority": None,
+            "dd_origin": None,
+            "span_links": [
+                SpanLink(
+                    trace_id=13088165645273925489,
+                    span_id=5678,
+                    tracestate=None,
+                    flags=1,
+                    attributes={"reason": "propagation_behavior_extract", "context_headers": "datadog"},
+                )
+            ],
+        },
+    ),
+    (
+        "valid_all_headers_trace_context_datadog_style_w_restart_behavior",
+        [_PROPAGATION_STYLE_W3C_TRACECONTEXT, PROPAGATION_STYLE_DATADOG],
+        _PROPAGATION_BEHAVIOR_RESTART,
+        ALL_HEADERS,
+        {
+            "trace_id": None,
+            "span_id": None,
+            "sampling_priority": None,
+            "dd_origin": None,
+            "span_links": [
+                SpanLink(
+                    trace_id=171395628812617415352188477958425669623,
+                    span_id=67667974448284343,
+                    tracestate="dd=s:2;o:rum;t.dm:-4;t.usr.id:baz64,congo=t61rcWkgMzE",
+                    flags=1,
+                    attributes={"reason": "propagation_behavior_extract", "context_headers": "tracecontext"},
+                )
+            ],
+        },
+    ),
+    (
+        "valid_all_headers_all_styles_w_restart_behavior",
+        [PROPAGATION_STYLE_B3_MULTI, PROPAGATION_STYLE_B3_SINGLE, _PROPAGATION_STYLE_W3C_TRACECONTEXT],
+        _PROPAGATION_BEHAVIOR_RESTART,
+        ALL_HEADERS,
+        {
+            "trace_id": None,
+            "span_id": None,
+            "sampling_priority": None,
+            "dd_origin": None,
+            "span_links": [
+                SpanLink(
+                    trace_id=171395628812617415352188477958425669623,
+                    span_id=67667974448284343,
+                    tracestate=None,
+                    flags=1,
+                    attributes={"reason": "propagation_behavior_extract", "context_headers": "b3multi"},
+                )
+            ],
+        },
+    ),
+    (
+        "valid_all_headers_and_baggage_trace_context_datadog_style_w_restart_behavior",
+        None,
+        _PROPAGATION_BEHAVIOR_RESTART,
+        {**ALL_HEADERS, **DATADOG_BAGGAGE_HEADERS_VALID},
+        {
+            "trace_id": None,
+            "span_id": None,
+            "sampling_priority": None,
+            "dd_origin": None,
+            "baggage": {"key1": "val1", "key2": "val2"},
+            "span_links": [
+                SpanLink(
+                    trace_id=13088165645273925489,
+                    span_id=5678,
+                    tracestate=None,
+                    flags=1,
+                    attributes={"reason": "propagation_behavior_extract", "context_headers": "datadog"},
+                )
+            ],
+        },
+    ),
 ]
 
 # Only add fixtures here if they can't pass both test_propagation_extract_env
@@ -2188,6 +2392,7 @@ def test_extract_tracecontext(headers, expected_context):
         # can't be tested correctly via test_propagation_extract_w_config. It is tested separately
         "valid_tracecontext_simple",
         [_PROPAGATION_STYLE_W3C_TRACECONTEXT],
+        None,
         TRACECONTEXT_HEADERS_VALID_BASIC,
         {
             "trace_id": TRACE_ID,
@@ -2204,6 +2409,7 @@ def test_extract_tracecontext(headers, expected_context):
     (
         "valid_tracecontext_rum_no_sampling_decision",
         [_PROPAGATION_STYLE_W3C_TRACECONTEXT],
+        None,
         TRACECONTEXT_HEADERS_VALID_RUM_NO_SAMPLING_DECISION,
         {
             "trace_id": TRACE_ID,
@@ -2218,8 +2424,12 @@ def test_extract_tracecontext(headers, expected_context):
 ]
 
 
-@pytest.mark.parametrize("name,styles,headers,expected_context", EXTRACT_FIXTURES + EXTRACT_FIXTURES_ENV_ONLY)
-def test_propagation_extract_env(name, styles, headers, expected_context, run_python_code_in_subprocess):
+@pytest.mark.parametrize(
+    "name,styles,extract_behavior,headers,expected_context", EXTRACT_FIXTURES + EXTRACT_FIXTURES_ENV_ONLY
+)
+def test_propagation_extract_env(
+    name, styles, extract_behavior, headers, expected_context, run_python_code_in_subprocess
+):
     # Execute the test code in isolation to ensure env variables work as expected
     code = """
 import json
@@ -2237,18 +2447,24 @@ def test_propagation_extract_env(name, styles, headers, expected_context, run_py
     env = os.environ.copy()
     if styles is not None:
         env["DD_TRACE_PROPAGATION_STYLE"] = ",".join(styles)
+    if extract_behavior is not None:
+        env["DD_TRACE_PROPAGATION_BEHAVIOR_EXTRACT"] = extract_behavior
     stdout, stderr, status, _ = run_python_code_in_subprocess(code=code, env=env)
     print(stderr, stdout)
     assert status == 0, (stdout, stderr)
 
 
-@pytest.mark.parametrize("name,styles,headers,expected_context", EXTRACT_FIXTURES)
-def test_propagation_extract_w_config(name, styles, headers, expected_context, run_python_code_in_subprocess):
+@pytest.mark.parametrize("name,styles,extract_behavior,headers,expected_context", EXTRACT_FIXTURES)
+def test_propagation_extract_w_config(
+    name, styles, extract_behavior, headers, expected_context, run_python_code_in_subprocess
+):
     # Setting via ddtrace.config works as expected too
     # DEV: This also helps us get code coverage reporting
     overrides = {}
     if styles is not None:
         overrides["_propagation_style_extract"] = styles
+    if extract_behavior is not None:
+        overrides["_propagation_behavior_extract"] = extract_behavior
         with override_global_config(overrides):
             context = HTTPPropagator.extract(headers)
             if not expected_context.get("tracestate"):

From 8ce6f80b3b30651041058d21c64c1babafb50eef Mon Sep 17 00:00:00 2001
From: ZStriker19 <zach.groves@datadoghq.com>
Date: Fri, 20 Dec 2024 15:21:20 -0500
Subject: [PATCH 05/17] allow override of config

---
 tests/utils.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tests/utils.py b/tests/utils.py
index de0129f75a3..5b98fe42d1b 100644
--- a/tests/utils.py
+++ b/tests/utils.py
@@ -123,6 +123,7 @@ def override_global_config(values):
         "_health_metrics_enabled",
         "_propagation_style_extract",
         "_propagation_style_inject",
+        "_propagation_behavior_extract",
         "_x_datadog_tags_max_length",
         "_128_bit_trace_id_enabled",
         "_x_datadog_tags_enabled",

From ffd8fe2e709db97c7e81f6f12595af702e4343cb Mon Sep 17 00:00:00 2001
From: ZStriker19 <zach.groves@datadoghq.com>
Date: Fri, 20 Dec 2024 15:43:28 -0500
Subject: [PATCH 06/17] add ref for system-tests

---
 .github/workflows/system-tests.yml | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/.github/workflows/system-tests.yml b/.github/workflows/system-tests.yml
index ccf6c6501d9..c525c1e5978 100644
--- a/.github/workflows/system-tests.yml
+++ b/.github/workflows/system-tests.yml
@@ -20,6 +20,7 @@ jobs:
         with:
           persist-credentials: false
           repository: 'DataDog/system-tests'
+          ref: 'zach.montoya/poc/propagation-behavior'
 
       - name: Build agent
         run: ./build.sh -i agent
@@ -65,6 +66,7 @@ jobs:
         with:
           persist-credentials: false
           repository: 'DataDog/system-tests'
+          ref: 'zach.montoya/poc/propagation-behavior'
 
       - name: Checkout dd-trace-py
         uses: actions/checkout@v4
@@ -117,6 +119,8 @@ jobs:
         with:
           persist-credentials: false
           repository: 'DataDog/system-tests'
+          ref: 'zach.montoya/poc/propagation-behavior'
+
 
       - name: Build runner
         uses: ./.github/actions/install_runner
@@ -290,6 +294,7 @@ jobs:
         with:
           persist-credentials: false
           repository: 'DataDog/system-tests'
+          ref: 'zach.montoya/poc/propagation-behavior'
       - name: Checkout dd-trace-py
         uses: actions/checkout@v4
         with:

From 290d9e66a34368da983c2068d935d76c8d9e358e Mon Sep 17 00:00:00 2001
From: ZStriker19 <zach.groves@datadoghq.com>
Date: Fri, 20 Dec 2024 17:24:28 -0500
Subject: [PATCH 07/17] add tracecontext headers to default case

---
 tests/tracer/test_propagation.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tests/tracer/test_propagation.py b/tests/tracer/test_propagation.py
index 150dbb1b704..4e330ccb886 100644
--- a/tests/tracer/test_propagation.py
+++ b/tests/tracer/test_propagation.py
@@ -2297,10 +2297,10 @@ def test_extract_tracecontext(headers, expected_context):
         },
     ),
     (
-        "valid_datadog_and_baggage_default_w_restart_behavior",
+        "valid_datadog_tracecontext_and_baggage_default_w_restart_behavior",
         None,
         _PROPAGATION_BEHAVIOR_RESTART,
-        DATADOG_BAGGAGE_HEADERS_VALID,
+        {**DATADOG_BAGGAGE_HEADERS_VALID, **TRACECONTEXT_HEADERS_VALID},
         {
             "trace_id": None,
             "span_id": None,

From 87532da8eddf1bd23ecab235bbc38f5afca4c22e Mon Sep 17 00:00:00 2001
From: ZStriker19 <zach.groves@datadoghq.com>
Date: Tue, 7 Jan 2025 14:52:42 -0500
Subject: [PATCH 08/17] don't drop extract contexts lacking trace_id

---
 ddtrace/contrib/trace_utils.py   |  4 ++--
 tests/tracer/test_propagation.py | 16 ++++++++--------
 2 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/ddtrace/contrib/trace_utils.py b/ddtrace/contrib/trace_utils.py
index db8509d8c35..740ae9288b7 100644
--- a/ddtrace/contrib/trace_utils.py
+++ b/ddtrace/contrib/trace_utils.py
@@ -565,7 +565,7 @@ def activate_distributed_headers(tracer, int_config=None, request_headers=None,
         context = HTTPPropagator.extract(request_headers)
 
         # Only need to activate the new context if something was propagated
-        if not context.trace_id:
+        if not context.trace_id or context._baggage:
             return None
 
         # Do not reactivate a context with the same trace id
@@ -577,7 +577,7 @@ def activate_distributed_headers(tracer, int_config=None, request_headers=None,
         #     app = Flask(__name__)  # Traced via Flask instrumentation
         #     app = DDWSGIMiddleware(app)  # Extra layer on top for WSGI
         current_context = tracer.current_trace_context()
-        if current_context and current_context.trace_id == context.trace_id:
+        if current_context and current_context.trace_id and current_context.trace_id == context.trace_id:
             log.debug(
                 "will not activate extracted Context(trace_id=%r, span_id=%r), a context with that trace id is already active",  # noqa: E501
                 context.trace_id,
diff --git a/tests/tracer/test_propagation.py b/tests/tracer/test_propagation.py
index 4e330ccb886..b2bd438032e 100644
--- a/tests/tracer/test_propagation.py
+++ b/tests/tracer/test_propagation.py
@@ -2494,14 +2494,14 @@ def test_propagation_extract_w_config(
         overrides["_propagation_style_extract"] = styles
     if extract_behavior is not None:
         overrides["_propagation_behavior_extract"] = extract_behavior
-        with override_global_config(overrides):
-            context = HTTPPropagator.extract(headers)
-            if not expected_context.get("tracestate"):
-                assert context == Context(**expected_context)
-            else:
-                copied_expectation = expected_context.copy()
-                tracestate = copied_expectation.pop("tracestate")
-                assert context == Context(**copied_expectation, meta={"tracestate": tracestate})
+    with override_global_config(overrides):
+        context = HTTPPropagator.extract(headers)
+        if not expected_context.get("tracestate"):
+            assert context == Context(**expected_context)
+        else:
+            copied_expectation = expected_context.copy()
+            tracestate = copied_expectation.pop("tracestate")
+            assert context == Context(**copied_expectation, meta={"tracestate": tracestate})
 
 
 EXTRACT_OVERRIDE_FIXTURES = [

From b32a467c76294494a5c6349075b0fada06765650 Mon Sep 17 00:00:00 2001
From: ZStriker19 <zach.groves@datadoghq.com>
Date: Wed, 8 Jan 2025 17:25:43 -0500
Subject: [PATCH 09/17] fix extracting baggage and update so that baggage only
 context is used

---
 ddtrace/contrib/trace_utils.py | 4 +---
 ddtrace/propagation/http.py    | 3 ++-
 2 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/ddtrace/contrib/trace_utils.py b/ddtrace/contrib/trace_utils.py
index 740ae9288b7..f168f7e2717 100644
--- a/ddtrace/contrib/trace_utils.py
+++ b/ddtrace/contrib/trace_utils.py
@@ -560,14 +560,12 @@ def activate_distributed_headers(tracer, int_config=None, request_headers=None,
     """
     if override is False:
         return None
-
     if override or (int_config and distributed_tracing_enabled(int_config)):
         context = HTTPPropagator.extract(request_headers)
 
         # Only need to activate the new context if something was propagated
-        if not context.trace_id or context._baggage:
+        if not context.trace_id and not context._baggage:
             return None
-
         # Do not reactivate a context with the same trace id
         # DEV: An example could be nested web frameworks, when one layer already
         #      parsed request headers and activated them.
diff --git a/ddtrace/propagation/http.py b/ddtrace/propagation/http.py
index 6d7cd8325ab..cae4d97a0b9 100644
--- a/ddtrace/propagation/http.py
+++ b/ddtrace/propagation/http.py
@@ -103,6 +103,7 @@ def _possible_header(header):
 _POSSIBLE_HTTP_HEADER_B3_FLAGS = _possible_header(_HTTP_HEADER_B3_FLAGS)
 _POSSIBLE_HTTP_HEADER_TRACEPARENT = _possible_header(_HTTP_HEADER_TRACEPARENT)
 _POSSIBLE_HTTP_HEADER_TRACESTATE = _possible_header(_HTTP_HEADER_TRACESTATE)
+_POSSIBLE_HTTP_BAGGAGE_HEADER = _possible_header(_HTTP_HEADER_BAGGAGE)
 
 
 # https://www.w3.org/TR/trace-context/#traceparent-header-field-values
@@ -939,7 +940,7 @@ def _inject(span_context: Context, headers: Dict[str, str]) -> None:
 
     @staticmethod
     def _extract(headers: Dict[str, str]) -> Context:
-        header_value = headers.get(_HTTP_HEADER_BAGGAGE)
+        header_value = _extract_header_value(_POSSIBLE_HTTP_BAGGAGE_HEADER, headers)
 
         if not header_value:
             return Context(baggage={})

From 837e2136b9e88e738e20b724de76cadbfcee17e5 Mon Sep 17 00:00:00 2001
From: ZStriker19 <zach.groves@datadoghq.com>
Date: Thu, 9 Jan 2025 13:29:56 -0500
Subject: [PATCH 10/17] fix no span on execution context error

---
 ddtrace/contrib/trace_utils.py | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/ddtrace/contrib/trace_utils.py b/ddtrace/contrib/trace_utils.py
index f168f7e2717..5694ff63007 100644
--- a/ddtrace/contrib/trace_utils.py
+++ b/ddtrace/contrib/trace_utils.py
@@ -575,7 +575,10 @@ def activate_distributed_headers(tracer, int_config=None, request_headers=None,
         #     app = Flask(__name__)  # Traced via Flask instrumentation
         #     app = DDWSGIMiddleware(app)  # Extra layer on top for WSGI
         current_context = tracer.current_trace_context()
-        if current_context and current_context.trace_id and current_context.trace_id == context.trace_id:
+
+        # We accept incoming contexts with only baggage, however if we
+        # already have a current_context then a baggage only context will be tossed out
+        if current_context and (not context.trace_id or current_context.trace_id == context.trace_id):
             log.debug(
                 "will not activate extracted Context(trace_id=%r, span_id=%r), a context with that trace id is already active",  # noqa: E501
                 context.trace_id,

From 44368964881079a2211fe96de512c90268b05008 Mon Sep 17 00:00:00 2001
From: ZStriker19 <zach.groves@datadoghq.com>
Date: Thu, 9 Jan 2025 14:02:35 -0500
Subject: [PATCH 11/17] cover case of only span_link

---
 ddtrace/contrib/trace_utils.py   | 7 ++++---
 tests/tracer/test_propagation.py | 1 +
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/ddtrace/contrib/trace_utils.py b/ddtrace/contrib/trace_utils.py
index 5694ff63007..75a44d3db59 100644
--- a/ddtrace/contrib/trace_utils.py
+++ b/ddtrace/contrib/trace_utils.py
@@ -564,7 +564,8 @@ def activate_distributed_headers(tracer, int_config=None, request_headers=None,
         context = HTTPPropagator.extract(request_headers)
 
         # Only need to activate the new context if something was propagated
-        if not context.trace_id and not context._baggage:
+        # The new context must have one of these values in order for it to be activated
+        if not context.trace_id and not context._baggage and not context._span_links:
             return None
         # Do not reactivate a context with the same trace id
         # DEV: An example could be nested web frameworks, when one layer already
@@ -576,8 +577,8 @@ def activate_distributed_headers(tracer, int_config=None, request_headers=None,
         #     app = DDWSGIMiddleware(app)  # Extra layer on top for WSGI
         current_context = tracer.current_trace_context()
 
-        # We accept incoming contexts with only baggage, however if we
-        # already have a current_context then a baggage only context will be tossed out
+        # We accept incoming contexts with only baggage or only span_links, however if we
+        # already have a current_context then a baggage only or span_link only context will be tossed out
         if current_context and (not context.trace_id or current_context.trace_id == context.trace_id):
             log.debug(
                 "will not activate extracted Context(trace_id=%r, span_id=%r), a context with that trace id is already active",  # noqa: E501
diff --git a/tests/tracer/test_propagation.py b/tests/tracer/test_propagation.py
index 7caab0c8aff..b6368c71140 100644
--- a/tests/tracer/test_propagation.py
+++ b/tests/tracer/test_propagation.py
@@ -1939,6 +1939,7 @@ def test_extract_tracecontext(headers, expected_context):
     (
         "baggage_case_insensitive",
         None,
+        None,
         {"BAgGage": "key1=val1,key2=val2"},
         {
             "baggage": {"key1": "val1", "key2": "val2"},

From 57b32392422214d3423ea95c5dfac7bf6490ec95 Mon Sep 17 00:00:00 2001
From: ZStriker19 <zach.groves@datadoghq.com>
Date: Thu, 9 Jan 2025 16:01:25 -0500
Subject: [PATCH 12/17] make sure span_link always added to root_span

---
 ddtrace/_trace/tracer.py | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/ddtrace/_trace/tracer.py b/ddtrace/_trace/tracer.py
index af9b09d3e02..4486e14cd7e 100644
--- a/ddtrace/_trace/tracer.py
+++ b/ddtrace/_trace/tracer.py
@@ -773,10 +773,8 @@ def _start_span(
 
         # Update the service name based on any mapping
         service = config.service_mapping.get(service, service)
-
         links = context._span_links if not parent else []
-
-        if trace_id:
+        if trace_id or links:
             # child_of a non-empty context, so either a local child span or from a remote context
             span = Span(
                 name=name,

From a0b2c34532a6bd88604808d69c36ccf98e8b855e Mon Sep 17 00:00:00 2001
From: Zachary Groves <32471391+ZStriker19@users.noreply.github.com>
Date: Fri, 10 Jan 2025 13:12:31 -0500
Subject: [PATCH 13/17] Update ddtrace/_trace/tracer.py

---
 ddtrace/_trace/tracer.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/ddtrace/_trace/tracer.py b/ddtrace/_trace/tracer.py
index 4486e14cd7e..aa891f289a1 100644
--- a/ddtrace/_trace/tracer.py
+++ b/ddtrace/_trace/tracer.py
@@ -773,6 +773,7 @@ def _start_span(
 
         # Update the service name based on any mapping
         service = config.service_mapping.get(service, service)
+
         links = context._span_links if not parent else []
         if trace_id or links:
             # child_of a non-empty context, so either a local child span or from a remote context

From cf57ae8f4b8900eda126298532b90a47a74244df Mon Sep 17 00:00:00 2001
From: Zachary Groves <32471391+ZStriker19@users.noreply.github.com>
Date: Fri, 10 Jan 2025 13:13:26 -0500
Subject: [PATCH 14/17] Update ddtrace/contrib/trace_utils.py

---
 ddtrace/contrib/trace_utils.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/ddtrace/contrib/trace_utils.py b/ddtrace/contrib/trace_utils.py
index 75a44d3db59..326074ea69d 100644
--- a/ddtrace/contrib/trace_utils.py
+++ b/ddtrace/contrib/trace_utils.py
@@ -560,6 +560,7 @@ def activate_distributed_headers(tracer, int_config=None, request_headers=None,
     """
     if override is False:
         return None
+
     if override or (int_config and distributed_tracing_enabled(int_config)):
         context = HTTPPropagator.extract(request_headers)
 

From d5293e08e7a715fab68f8270e390e43c6a68b31a Mon Sep 17 00:00:00 2001
From: ZStriker19 <zach.groves@datadoghq.com>
Date: Fri, 10 Jan 2025 13:43:49 -0500
Subject: [PATCH 15/17] use public api to access baggage

---
 ddtrace/propagation/http.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/ddtrace/propagation/http.py b/ddtrace/propagation/http.py
index cae4d97a0b9..681ce5436d8 100644
--- a/ddtrace/propagation/http.py
+++ b/ddtrace/propagation/http.py
@@ -1175,7 +1175,7 @@ def my_controller(url, headers):
                 baggage_context = _BaggageHeader._extract(normalized_headers)
                 if baggage_context._baggage != {}:
                     if context:
-                        context._baggage = baggage_context._baggage
+                        context._baggage = baggage_context.get_all_baggage_items()
                     else:
                         context = baggage_context
             if config._propagation_behavior_extract == _PROPAGATION_BEHAVIOR_RESTART:

From af2c94fa807670110a14a5fa7636456cb25f625d Mon Sep 17 00:00:00 2001
From: ZStriker19 <zach.groves@datadoghq.com>
Date: Fri, 10 Jan 2025 13:45:03 -0500
Subject: [PATCH 16/17] fix merge conflict

---
 pyproject.toml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pyproject.toml b/pyproject.toml
index 855c67e36f9..df5fbdcdbb2 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -74,7 +74,7 @@ Homepage = "https://github.com/DataDog/dd-trace-py"
 "Source Code" = "https://github.com/DataDog/dd-trace-py/"
 
 [tool.setuptools_scm]
-version_scheme = "guess-next-dev"  # Must be "release-branch-semver" for now in main, see https://github.com/DataDog/dd-trace-py/issues/8801
+version_scheme = "release-branch-semver"  # Must be "release-branch-semver" for now in main, see https://github.com/DataDog/dd-trace-py/issues/8801
 write_to = "ddtrace/_version.py"
 
 [tool.cython-lint]

From 37117d2c2fbd5eb44061a0b6250e46f63b6a28c7 Mon Sep 17 00:00:00 2001
From: ZStriker19 <zach.groves@datadoghq.com>
Date: Fri, 10 Jan 2025 14:06:54 -0500
Subject: [PATCH 17/17] docs and update rn

---
 docs/configuration.rst                        | 20 +++++++++++++++++++
 ...ion_behavior_extract-3d16765cfd07485b.yaml |  5 +++--
 2 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/docs/configuration.rst b/docs/configuration.rst
index 35bb63fac20..455272f318d 100644
--- a/docs/configuration.rst
+++ b/docs/configuration.rst
@@ -368,6 +368,26 @@ Trace Context propagation
      version_added:
        v1.7.0: The ``b3multi`` propagation style was added and ``b3`` was deprecated in favor it.
 
+   DD_TRACE_PROPAGATION_BEHAVIOR_EXTRACT:
+     default: |
+         ``continue``
+     
+     description: |
+         String for how to handle incoming request headers that are extracted for propagation of trace info.
+
+         The supported values are ``continue``, ``restart``, and ``ignore``.
+
+         After extracting the headers for propagation, this configuration determines what is done with them.
+
+         The default value is ``continue`` which always propagates valid headers.
+         ``ignore`` ignores all incoming headers and ``restart`` turns the first extracted valid propagation header 
+         into a span link and propagates baggage if present.
+
+         Example: ``DD_TRACE_PROPAGATION_STYLE_EXTRACT="ignore"`` to ignore all incoming headers and to start a root span without a parent.
+
+     version_added:
+       v2.20.0:
+
    DD_TRACE_PROPAGATION_STYLE_INJECT:
      default: |
          ``tracecontext,datadog``
diff --git a/releasenotes/notes/propagation_behavior_extract-3d16765cfd07485b.yaml b/releasenotes/notes/propagation_behavior_extract-3d16765cfd07485b.yaml
index 8e34092a6bb..9aa0f5ce208 100644
--- a/releasenotes/notes/propagation_behavior_extract-3d16765cfd07485b.yaml
+++ b/releasenotes/notes/propagation_behavior_extract-3d16765cfd07485b.yaml
@@ -3,5 +3,6 @@ features:
   - |
     propagation: This introduces the environment variable ``DD_TRACE_PROPAGATION_BEHAVIOR_EXTRACT`` 
     to control the behavior of the extraction of distributed tracing headers. The values, ``continue`` (default),
-    ``ignore``, and ``restart``, are supported. The default value is ``continue`` which should have no change from the current behavior of always propagating valid headers.
-    With ``ignore`` ignoring all incoming headers and with ``restart`` turning incoming headers into a span links and propagating baggage items.
+    ``ignore``, and ``restart``, are supported. The default value is ``continue`` which has no change from the current behavior of always propagating valid headers.
+    ``ignore`` ignores all incoming headers, never propagating the incoming trace information
+    and ``restart`` turns the first extracted propagation style into a span link and propagates baggage if extracted.