From 4f7098c59496072625406c822be3e10c5bd05661 Mon Sep 17 00:00:00 2001
From: Christopher Bremner <chrisjbremner@gmail.com>
Date: Wed, 30 Dec 2020 12:06:52 -0800
Subject: [PATCH 01/12] Add Windows support to file locking

---
 pex/common.py | 25 ++++++++++++++++++++++---
 1 file changed, 22 insertions(+), 3 deletions(-)

diff --git a/pex/common.py b/pex/common.py
index d4d8e421e..071df3446 100644
--- a/pex/common.py
+++ b/pex/common.py
@@ -6,7 +6,6 @@
 import atexit
 import contextlib
 import errno
-import fcntl
 import os
 import re
 import shutil
@@ -21,8 +20,14 @@
 from datetime import datetime
 from uuid import uuid4
 
+from pex.compatibility import WINDOWS
 from pex.typing import TYPE_CHECKING
 
+if WINDOWS:
+    import msvcrt
+else:
+    import fcntl
+
 if TYPE_CHECKING:
     from typing import Any, DefaultDict, Iterable, Iterator, NoReturn, Optional, Set, Sized
 
@@ -393,7 +398,10 @@ def unlock():
         if lock_fd is None:
             return
         try:
-            fcntl.lockf(lock_fd, fcntl.LOCK_UN)
+            if WINDOWS:
+                msvcrt.locking(lock_fd, msvcrt.LK_UNLCK, 1)
+            else:
+                fcntl.lockf(lock_fd, fcntl.LOCK_UN)
         finally:
             os.close(lock_fd)
 
@@ -410,7 +418,18 @@ def unlock():
         # N.B.: Since lockf operates on an open file descriptor and these are guaranteed to be
         # closed by the operating system when the owning process exits, this lock is immune to
         # staleness.
-        fcntl.lockf(lock_fd, fcntl.LOCK_EX)  # A blocking write lock.
+        if WINDOWS:
+            while True:
+                # Force the non-blocking lock to be blocking. LK_LOCK is msvcrt's implementation of
+                # a blocking lock, but it only tries 10 times, once per second before rasing an
+                # OSError.
+                try:
+                    msvcrt.locking(lock_fd, msvcrt.LK_NBLCK, 1)
+                    break
+                except OSError:
+                    safe_sleep(1)
+        else:
+            fcntl.lockf(lock_fd, fcntl.LOCK_EX)  # A blocking write lock.
         if atomic_dir.is_finalized:
             # We lost the double-checked locking race and our work was done for us by the race
             # winner so exit early.

From edc84354c38a4d422fc551f58564a8323cadbf06 Mon Sep 17 00:00:00 2001
From: Christopher Bremner <chrisjbremner@gmail.com>
Date: Wed, 30 Dec 2020 13:42:02 -0800
Subject: [PATCH 02/12] Use LK_LOCK

---
 pex/common.py | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/pex/common.py b/pex/common.py
index 071df3446..8b5adc6dd 100644
--- a/pex/common.py
+++ b/pex/common.py
@@ -424,9 +424,12 @@ def unlock():
                 # a blocking lock, but it only tries 10 times, once per second before rasing an
                 # OSError.
                 try:
-                    msvcrt.locking(lock_fd, msvcrt.LK_NBLCK, 1)
+                    msvcrt.locking(lock_fd, msvcrt.LK_LOCK, 1)
                     break
-                except OSError:
+                except OSError as ex:
+                    # Deadlock error is raised after failing to lock the file
+                    if ex.errno != errno.EDEADLOCK:
+                        raise
                     safe_sleep(1)
         else:
             fcntl.lockf(lock_fd, fcntl.LOCK_EX)  # A blocking write lock.

From 041aa5ef72771fb43ef78612be287f1276c3cc22 Mon Sep 17 00:00:00 2001
From: Christopher Bremner <chrisjbremner@gmail.com>
Date: Wed, 30 Dec 2020 14:45:49 -0800
Subject: [PATCH 03/12] Add CI for Windows

---
 .travis.yml | 56 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 55 insertions(+), 1 deletion(-)

diff --git a/.travis.yml b/.travis.yml
index 2cc480f39..7d21d408e 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -51,6 +51,9 @@ x-pyenv-install: &x-pyenv-install |
   "${PYENV}" install --keep --skip-existing ${PYENV_VERSION}
   "${PYENV}" global ${PYENV_VERSION}
 
+x-pyenv-27-env: &x-pyenv-27-env >
+  PYENV_VERSION=2.7.18
+
 x-pyenv-39-env: &x-pyenv-39-env >
   PYENV_VERSION=3.9.1
 
@@ -89,7 +92,7 @@ x-osx-27-shard: &x-osx-27-shard
   env:
     - *x-tox-env
     - *x-pyenv-env
-    - PYENV_VERSION=2.7.18
+    - *x-pyenv-27-env
 
 x-osx-39-shard: &x-osx-39-shard
   <<: *x-osx-shard
@@ -98,6 +101,41 @@ x-osx-39-shard: &x-osx-39-shard
     - *x-pyenv-env
     - *x-pyenv-39-env
 
+x-windows-shard: &x-windows-shard
+  os: windows
+  language: shell
+  cache:
+    # The default is 3 minutes (180).
+    timeout: 300
+    directories:
+      - .pyenv_test
+      - "${PYENV_ROOT}"
+  install:
+    - *x-tox-install
+    - *x-pyenv-install
+
+x-windows-27-shard: &x-windows-27-shard
+  <<: *x-windows-shard
+  before_install:
+  - choco install python2
+  - python -m pip install --upgrade pip
+  env:
+    - PATH=/c/Python27:/c/Python27/Scripts:$PATH
+    - *x-tox-env
+    - *x-pyenv-env
+    - *x-pyenv-27-env
+
+x-windows-39-shard: &x-windows-39-shard
+  <<: *x-windows-shard
+  before_install:
+  - choco install python --version 3.9.0
+  - python -m pip install --upgrade pip
+  env:
+    - PATH=/c/Python39:/c/Python39/Scripts:$PATH
+    - *x-tox-env
+    - *x-pyenv-env
+    - *x-pyenv-39-env
+
 # NB: Travis partitions caches using a combination of os, language amd env vars. As such, we do not
 # use TOXENV and instead pass the toxenv via -e on the command line. This helps ensure we share
 # caches as much as possible (eg: all linux python 2.7.15 shards share a cache).
@@ -177,3 +215,19 @@ matrix:
     - <<: *x-osx-39-shard
       name: TOXENV=py39-integration
       script: ${TOX_CMD} -e py39-integration
+
+    - <<: *x-windows-27-shard
+      name: TOXENV=py27
+      script: ${TOX_CMD} -e py27
+
+    - <<: *x-windows-39-shard
+      name: TOXENV=py39
+      script: ${TOX_CMD} -e py39
+
+    - <<: *x-windows-27-shard
+      name: TOXENV=py27-integration
+      script: ${TOX_CMD} -e py27-integration
+
+    - <<: *x-windows-39-shard
+      name: TOXENV=py39-integration
+      script: ${TOX_CMD} -e py39-integration

From 20e36c665fa268609a21e97a96ea7e746f255095 Mon Sep 17 00:00:00 2001
From: Christopher Bremner <chrisjbremner@gmail.com>
Date: Wed, 30 Dec 2020 15:29:17 -0800
Subject: [PATCH 04/12] Fix for Git Bash symlinks issue

---
 .travis.yml | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/.travis.yml b/.travis.yml
index 7d21d408e..e193071cf 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -41,8 +41,10 @@ x-pyenv-env: &x-pyenv-env >
   PATH="${PYENV_ROOT}/shims:${PATH}"
 
 x-pyenv-install: &x-pyenv-install |
-  # Ensure we have the targeted Python for tox to find on $PATH
-  PYENV="${PYENV_ROOT}/bin/pyenv"
+  # Ensure we have the targeted Python for tox to find on $PATH.
+  # Relative symlinks don't work on Git Bash, which is why
+  # "${PYENV_ROOT}/bin/pyenv" isn't used.
+  PYENV="${PYENV_ROOT}/libexec/pyenv"
   if [ ! -x "${PYENV}" ]; then
     rm -rf ${PYENV_ROOT}
     git clone https://github.com/pyenv/pyenv "${PYENV_ROOT}";

From c85a71a9a6c4742934f6ab1d2bcd8dc61648c7b6 Mon Sep 17 00:00:00 2001
From: Christopher Bremner <chrisjbremner@gmail.com>
Date: Wed, 30 Dec 2020 16:14:43 -0800
Subject: [PATCH 05/12] Use penv-win for Windows CI

---
 .travis.yml | 29 ++++++++++++++++++++---------
 1 file changed, 20 insertions(+), 9 deletions(-)

diff --git a/.travis.yml b/.travis.yml
index e193071cf..c5062b4a8 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -40,18 +40,23 @@ x-pyenv-env: &x-pyenv-env >
   PYENV_ROOT=~/.pyenv-pex
   PATH="${PYENV_ROOT}/shims:${PATH}"
 
+x-pyenv-unix-env: &x-pyenv-unix-env >
+  PYENV_CMD="${PYENV_ROOT}/bin/pyenv"
+  PYENV_REPO=https://github.com/pyenv/pyenv
+
+x-pyenv-windows-env: &x-pyenv-windows-env >
+  PYENV_CMD="${PYENV_ROOT}/pyenv-win/bin/pyenv"
+  PYENV_REPO=https://github.com/pyenv-win/pyenv-win
+
 x-pyenv-install: &x-pyenv-install |
-  # Ensure we have the targeted Python for tox to find on $PATH.
-  # Relative symlinks don't work on Git Bash, which is why
-  # "${PYENV_ROOT}/bin/pyenv" isn't used.
-  PYENV="${PYENV_ROOT}/libexec/pyenv"
+  # Ensure we have the targeted Python for tox to find on $PATH
   if [ ! -x "${PYENV}" ]; then
     rm -rf ${PYENV_ROOT}
-    git clone https://github.com/pyenv/pyenv "${PYENV_ROOT}";
+    git clone "${PYENV_REPO}" "${PYENV_ROOT}";
   fi
   GIT_DIR="${PYENV_ROOT}/.git" git pull --ff-only
-  "${PYENV}" install --keep --skip-existing ${PYENV_VERSION}
-  "${PYENV}" global ${PYENV_VERSION}
+  ./"${PYENV_CMD}" install --keep --skip-existing ${PYENV_VERSION}
+  ./"${PYENV_CMD}" global ${PYENV_VERSION}
 
 x-pyenv-27-env: &x-pyenv-27-env >
   PYENV_VERSION=2.7.18
@@ -94,6 +99,7 @@ x-osx-27-shard: &x-osx-27-shard
   env:
     - *x-tox-env
     - *x-pyenv-env
+    - *x-pyenv-unix-env
     - *x-pyenv-27-env
 
 x-osx-39-shard: &x-osx-39-shard
@@ -101,6 +107,7 @@ x-osx-39-shard: &x-osx-39-shard
   env:
     - *x-tox-env
     - *x-pyenv-env
+    - *x-pyenv-unix-env
     - *x-pyenv-39-env
 
 x-windows-shard: &x-windows-shard
@@ -125,7 +132,9 @@ x-windows-27-shard: &x-windows-27-shard
     - PATH=/c/Python27:/c/Python27/Scripts:$PATH
     - *x-tox-env
     - *x-pyenv-env
-    - *x-pyenv-27-env
+    - *x-pyenv-windows-env
+    # TODO: Use *x-pyenv-27-env when the pyenv-windows 2.7.18 image is available
+    - PYENV_VERSION=2.7.17
 
 x-windows-39-shard: &x-windows-39-shard
   <<: *x-windows-shard
@@ -136,7 +145,9 @@ x-windows-39-shard: &x-windows-39-shard
     - PATH=/c/Python39:/c/Python39/Scripts:$PATH
     - *x-tox-env
     - *x-pyenv-env
-    - *x-pyenv-39-env
+    - *x-pyenv-windows-env
+    # TODO: Use *x-pyenv-39-env when the pyenv-windows 3.9.1 image is available
+    - PYENV_VERSION=3.9.0a4
 
 # NB: Travis partitions caches using a combination of os, language amd env vars. As such, we do not
 # use TOXENV and instead pass the toxenv via -e on the command line. This helps ensure we share

From dd262d5e9c7785c747bb7a983532d9908eaaa617 Mon Sep 17 00:00:00 2001
From: Christopher Bremner <chrisjbremner@gmail.com>
Date: Wed, 30 Dec 2020 16:23:08 -0800
Subject: [PATCH 06/12] Pyenv install flags only work on Unix version

---
 .travis.yml | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/.travis.yml b/.travis.yml
index c5062b4a8..b07166fc2 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -43,6 +43,7 @@ x-pyenv-env: &x-pyenv-env >
 x-pyenv-unix-env: &x-pyenv-unix-env >
   PYENV_CMD="${PYENV_ROOT}/bin/pyenv"
   PYENV_REPO=https://github.com/pyenv/pyenv
+  PYENV_INSTALL_FLAGS="--keep --skip-existing"
 
 x-pyenv-windows-env: &x-pyenv-windows-env >
   PYENV_CMD="${PYENV_ROOT}/pyenv-win/bin/pyenv"
@@ -55,7 +56,7 @@ x-pyenv-install: &x-pyenv-install |
     git clone "${PYENV_REPO}" "${PYENV_ROOT}";
   fi
   GIT_DIR="${PYENV_ROOT}/.git" git pull --ff-only
-  ./"${PYENV_CMD}" install --keep --skip-existing ${PYENV_VERSION}
+  ./"${PYENV_CMD}" install ${PYENV_INSTALL_FLAGS} ${PYENV_VERSION}
   ./"${PYENV_CMD}" global ${PYENV_VERSION}
 
 x-pyenv-27-env: &x-pyenv-27-env >

From 186713ebc781a106e3dcac86bf5c48c596c0de05 Mon Sep 17 00:00:00 2001
From: Christopher Bremner <chrisjbremner@gmail.com>
Date: Wed, 30 Dec 2020 16:26:05 -0800
Subject: [PATCH 07/12] Don't use pyenv for Windows CI

---
 .travis.yml | 32 ++++----------------------------
 1 file changed, 4 insertions(+), 28 deletions(-)

diff --git a/.travis.yml b/.travis.yml
index b07166fc2..e3b1f70c8 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -40,24 +40,16 @@ x-pyenv-env: &x-pyenv-env >
   PYENV_ROOT=~/.pyenv-pex
   PATH="${PYENV_ROOT}/shims:${PATH}"
 
-x-pyenv-unix-env: &x-pyenv-unix-env >
-  PYENV_CMD="${PYENV_ROOT}/bin/pyenv"
-  PYENV_REPO=https://github.com/pyenv/pyenv
-  PYENV_INSTALL_FLAGS="--keep --skip-existing"
-
-x-pyenv-windows-env: &x-pyenv-windows-env >
-  PYENV_CMD="${PYENV_ROOT}/pyenv-win/bin/pyenv"
-  PYENV_REPO=https://github.com/pyenv-win/pyenv-win
-
 x-pyenv-install: &x-pyenv-install |
   # Ensure we have the targeted Python for tox to find on $PATH
+  PYENV="${PYENV_ROOT}/bin/pyenv"
   if [ ! -x "${PYENV}" ]; then
     rm -rf ${PYENV_ROOT}
-    git clone "${PYENV_REPO}" "${PYENV_ROOT}";
+    git clone https://github.com/pyenv/pyenv "${PYENV_ROOT}";
   fi
   GIT_DIR="${PYENV_ROOT}/.git" git pull --ff-only
-  ./"${PYENV_CMD}" install ${PYENV_INSTALL_FLAGS} ${PYENV_VERSION}
-  ./"${PYENV_CMD}" global ${PYENV_VERSION}
+  "${PYENV}" install --keep --skip-existing ${PYENV_VERSION}
+  "${PYENV}" global ${PYENV_VERSION}
 
 x-pyenv-27-env: &x-pyenv-27-env >
   PYENV_VERSION=2.7.18
@@ -100,7 +92,6 @@ x-osx-27-shard: &x-osx-27-shard
   env:
     - *x-tox-env
     - *x-pyenv-env
-    - *x-pyenv-unix-env
     - *x-pyenv-27-env
 
 x-osx-39-shard: &x-osx-39-shard
@@ -108,7 +99,6 @@ x-osx-39-shard: &x-osx-39-shard
   env:
     - *x-tox-env
     - *x-pyenv-env
-    - *x-pyenv-unix-env
     - *x-pyenv-39-env
 
 x-windows-shard: &x-windows-shard
@@ -117,12 +107,8 @@ x-windows-shard: &x-windows-shard
   cache:
     # The default is 3 minutes (180).
     timeout: 300
-    directories:
-      - .pyenv_test
-      - "${PYENV_ROOT}"
   install:
     - *x-tox-install
-    - *x-pyenv-install
 
 x-windows-27-shard: &x-windows-27-shard
   <<: *x-windows-shard
@@ -130,12 +116,7 @@ x-windows-27-shard: &x-windows-27-shard
   - choco install python2
   - python -m pip install --upgrade pip
   env:
-    - PATH=/c/Python27:/c/Python27/Scripts:$PATH
     - *x-tox-env
-    - *x-pyenv-env
-    - *x-pyenv-windows-env
-    # TODO: Use *x-pyenv-27-env when the pyenv-windows 2.7.18 image is available
-    - PYENV_VERSION=2.7.17
 
 x-windows-39-shard: &x-windows-39-shard
   <<: *x-windows-shard
@@ -143,12 +124,7 @@ x-windows-39-shard: &x-windows-39-shard
   - choco install python --version 3.9.0
   - python -m pip install --upgrade pip
   env:
-    - PATH=/c/Python39:/c/Python39/Scripts:$PATH
     - *x-tox-env
-    - *x-pyenv-env
-    - *x-pyenv-windows-env
-    # TODO: Use *x-pyenv-39-env when the pyenv-windows 3.9.1 image is available
-    - PYENV_VERSION=3.9.0a4
 
 # NB: Travis partitions caches using a combination of os, language amd env vars. As such, we do not
 # use TOXENV and instead pass the toxenv via -e on the command line. This helps ensure we share

From 9f953bdcc48fdc700729878026b3336adbc40fad Mon Sep 17 00:00:00 2001
From: Christopher Bremner <chrisjbremner@gmail.com>
Date: Wed, 30 Dec 2020 16:54:16 -0800
Subject: [PATCH 08/12] Use ensurepip

---
 .travis.yml | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/.travis.yml b/.travis.yml
index e3b1f70c8..007137965 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -114,15 +114,15 @@ x-windows-27-shard: &x-windows-27-shard
   <<: *x-windows-shard
   before_install:
   - choco install python2
-  - python -m pip install --upgrade pip
+  - python -m ensurepip --upgrade
   env:
     - *x-tox-env
 
 x-windows-39-shard: &x-windows-39-shard
   <<: *x-windows-shard
   before_install:
-  - choco install python --version 3.9.0
-  - python -m pip install --upgrade pip
+  - choco install python --version 3.9.1
+  - python -m ensurepip --upgrade
   env:
     - *x-tox-env
 

From b766f0865968f3690a10f567cc25ddc45dded8c3 Mon Sep 17 00:00:00 2001
From: Christopher Bremner <chrisjbremner@gmail.com>
Date: Wed, 30 Dec 2020 18:00:27 -0800
Subject: [PATCH 09/12] Use correct python

---
 .travis.yml | 156 ++++++++++++++++++++++++++--------------------------
 1 file changed, 78 insertions(+), 78 deletions(-)

diff --git a/.travis.yml b/.travis.yml
index 007137965..c55a7b1cf 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -2,8 +2,8 @@ x-tox-env: &x-tox-env >
   TOX_CMD="tox --skip-missing-interpreters=false -v"
 
 x-tox-install: &x-tox-install |
-  pip install -U pip
-  pip install 'tox<=3.14.5' 'virtualenv<20.0.5'
+  ${PIP_PATH:-pip} install -U pip
+  ${PIP_PATH:-pip} install 'tox<=3.14.5' 'virtualenv<20.0.5'
 
 x-linux-shard: &x-linux-shard
   os: linux
@@ -114,16 +114,16 @@ x-windows-27-shard: &x-windows-27-shard
   <<: *x-windows-shard
   before_install:
   - choco install python2
-  - python -m ensurepip --upgrade
   env:
+    - PIP_PATH="C:\Python27 -m pip"
     - *x-tox-env
 
 x-windows-39-shard: &x-windows-39-shard
   <<: *x-windows-shard
   before_install:
   - choco install python --version 3.9.1
-  - python -m ensurepip --upgrade
   env:
+    - PIP_PATH="C:\Python39 -m pip"
     - *x-tox-env
 
 # NB: Travis partitions caches using a combination of os, language amd env vars. As such, we do not
@@ -131,80 +131,80 @@ x-windows-39-shard: &x-windows-39-shard
 # caches as much as possible (eg: all linux python 2.7.15 shards share a cache).
 matrix:
   include:
-    - <<: *x-linux-shard
-      name: TOXENV=format-check
-      script: ${TOX_CMD} -e format-check
-
-    - <<: *x-linux-shard
-      name: TOXENV=typecheck
-      script: ${TOX_CMD} -e typecheck
-
-    - <<: *x-linux-38-shard
-      name: TOXENV=vendor-check
-      script: ${TOX_CMD} -e vendor-check
-
-    - <<: *x-linux-27-shard
-      name: TOXENV=py27
-      script: ${TOX_CMD} -e py27
-
-    - <<: *x-linux-27-shard
-      name: TOXENV=py27-subprocess
-      script: ${TOX_CMD} -e py27-subprocess
-
-    - <<: *x-linux-shard
-      name: TOXENV=py35
-      python: 3.5.9
-      script: ${TOX_CMD} -e py35
-
-    - <<: *x-linux-shard
-      name: TOXENV=py36
-      python: 3.6.10
-      script: ${TOX_CMD} -e py36
-
-    - <<: *x-linux-shard
-      name: TOXENV=py37
-      python: 3.7.7
-      script: ${TOX_CMD} -e py37
-
-    - <<: *x-linux-38-shard
-      name: TOXENV=py38
-      script: ${TOX_CMD} -e py38
-
-    - <<: *x-linux-39-shard
-      name: TOXENV=py39
-      script: ${TOX_CMD} -e py39
-
-    - <<: *x-linux-pypy-shard
-      name: TOXENV=pypy
-      script: ${TOX_CMD} -e pypy
-
-    - <<: *x-linux-27-shard
-      name: TOXENV=py27-integration
-      script: ${TOX_CMD} -e py27-integration
-
-    - <<: *x-linux-39-shard
-      name: TOXENV=py39-integration
-      script: ${TOX_CMD} -e py39-integration
-
-    - <<: *x-linux-pypy-shard
-      name: TOXENV=pypy-integration
-      script: ${TOX_CMD} -e pypy-integration
-
-    - <<: *x-osx-27-shard
-      name: TOXENV=py27
-      script: ${TOX_CMD} -e py27
-
-    - <<: *x-osx-39-shard
-      name: TOXENV=py39
-      script: ${TOX_CMD} -e py39
-
-    - <<: *x-osx-27-shard
-      name: TOXENV=py27-integration
-      script: ${TOX_CMD} -e py27-integration
-
-    - <<: *x-osx-39-shard
-      name: TOXENV=py39-integration
-      script: ${TOX_CMD} -e py39-integration
+    # - <<: *x-linux-shard
+    #   name: TOXENV=format-check
+    #   script: ${TOX_CMD} -e format-check
+
+    # - <<: *x-linux-shard
+    #   name: TOXENV=typecheck
+    #   script: ${TOX_CMD} -e typecheck
+
+    # - <<: *x-linux-38-shard
+    #   name: TOXENV=vendor-check
+    #   script: ${TOX_CMD} -e vendor-check
+
+    # - <<: *x-linux-27-shard
+    #   name: TOXENV=py27
+    #   script: ${TOX_CMD} -e py27
+
+    # - <<: *x-linux-27-shard
+    #   name: TOXENV=py27-subprocess
+    #   script: ${TOX_CMD} -e py27-subprocess
+
+    # - <<: *x-linux-shard
+    #   name: TOXENV=py35
+    #   python: 3.5.9
+    #   script: ${TOX_CMD} -e py35
+
+    # - <<: *x-linux-shard
+    #   name: TOXENV=py36
+    #   python: 3.6.10
+    #   script: ${TOX_CMD} -e py36
+
+    # - <<: *x-linux-shard
+    #   name: TOXENV=py37
+    #   python: 3.7.7
+    #   script: ${TOX_CMD} -e py37
+
+    # - <<: *x-linux-38-shard
+    #   name: TOXENV=py38
+    #   script: ${TOX_CMD} -e py38
+
+    # - <<: *x-linux-39-shard
+    #   name: TOXENV=py39
+    #   script: ${TOX_CMD} -e py39
+
+    # - <<: *x-linux-pypy-shard
+    #   name: TOXENV=pypy
+    #   script: ${TOX_CMD} -e pypy
+
+    # - <<: *x-linux-27-shard
+    #   name: TOXENV=py27-integration
+    #   script: ${TOX_CMD} -e py27-integration
+
+    # - <<: *x-linux-39-shard
+    #   name: TOXENV=py39-integration
+    #   script: ${TOX_CMD} -e py39-integration
+
+    # - <<: *x-linux-pypy-shard
+    #   name: TOXENV=pypy-integration
+    #   script: ${TOX_CMD} -e pypy-integration
+
+    # - <<: *x-osx-27-shard
+    #   name: TOXENV=py27
+    #   script: ${TOX_CMD} -e py27
+
+    # - <<: *x-osx-39-shard
+    #   name: TOXENV=py39
+    #   script: ${TOX_CMD} -e py39
+
+    # - <<: *x-osx-27-shard
+    #   name: TOXENV=py27-integration
+    #   script: ${TOX_CMD} -e py27-integration
+
+    # - <<: *x-osx-39-shard
+    #   name: TOXENV=py39-integration
+    #   script: ${TOX_CMD} -e py39-integration
 
     - <<: *x-windows-27-shard
       name: TOXENV=py27

From 81445c67a3aef0597d6ede72aa3eeb07172f6aa9 Mon Sep 17 00:00:00 2001
From: Christopher Bremner <chrisjbremner@gmail.com>
Date: Wed, 30 Dec 2020 18:02:38 -0800
Subject: [PATCH 10/12] Use Python executable

---
 .travis.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.travis.yml b/.travis.yml
index c55a7b1cf..db39a1997 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -115,7 +115,7 @@ x-windows-27-shard: &x-windows-27-shard
   before_install:
   - choco install python2
   env:
-    - PIP_PATH="C:\Python27 -m pip"
+    - PIP_PATH="C:\Python27\python.exe -m pip"
     - *x-tox-env
 
 x-windows-39-shard: &x-windows-39-shard
@@ -123,7 +123,7 @@ x-windows-39-shard: &x-windows-39-shard
   before_install:
   - choco install python --version 3.9.1
   env:
-    - PIP_PATH="C:\Python39 -m pip"
+    - PIP_PATH="C:\Python39\python.exe -m pip"
     - *x-tox-env
 
 # NB: Travis partitions caches using a combination of os, language amd env vars. As such, we do not

From 9735cadcd4f2be172aa301b7b8a0753baba57245 Mon Sep 17 00:00:00 2001
From: Christopher Bremner <chrisjbremner@gmail.com>
Date: Wed, 30 Dec 2020 18:10:29 -0800
Subject: [PATCH 11/12] Add correct tox path

---
 .travis.yml | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/.travis.yml b/.travis.yml
index db39a1997..002b98174 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,5 +1,5 @@
 x-tox-env: &x-tox-env >
-  TOX_CMD="tox --skip-missing-interpreters=false -v"
+  TOX_CMD="${TOX_PATH:-tox} --skip-missing-interpreters=false -v"
 
 x-tox-install: &x-tox-install |
   ${PIP_PATH:-pip} install -U pip
@@ -116,6 +116,7 @@ x-windows-27-shard: &x-windows-27-shard
   - choco install python2
   env:
     - PIP_PATH="C:\Python27\python.exe -m pip"
+    - TOX_PATH="C:\Python27\Scripts\tox"
     - *x-tox-env
 
 x-windows-39-shard: &x-windows-39-shard
@@ -124,6 +125,7 @@ x-windows-39-shard: &x-windows-39-shard
   - choco install python --version 3.9.1
   env:
     - PIP_PATH="C:\Python39\python.exe -m pip"
+    - TOX_PATH="C:\Python39\Scripts\tox"
     - *x-tox-env
 
 # NB: Travis partitions caches using a combination of os, language amd env vars. As such, we do not

From 54c6c74f84c1c680ad5fe072077133534e0f2e0c Mon Sep 17 00:00:00 2001
From: Christopher Bremner <chrisjbremner@gmail.com>
Date: Wed, 30 Dec 2020 18:26:04 -0800
Subject: [PATCH 12/12] Restore commented out shards

---
 .travis.yml | 148 ++++++++++++++++++++++++++--------------------------
 1 file changed, 74 insertions(+), 74 deletions(-)

diff --git a/.travis.yml b/.travis.yml
index 002b98174..6ca06e3de 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -133,80 +133,80 @@ x-windows-39-shard: &x-windows-39-shard
 # caches as much as possible (eg: all linux python 2.7.15 shards share a cache).
 matrix:
   include:
-    # - <<: *x-linux-shard
-    #   name: TOXENV=format-check
-    #   script: ${TOX_CMD} -e format-check
-
-    # - <<: *x-linux-shard
-    #   name: TOXENV=typecheck
-    #   script: ${TOX_CMD} -e typecheck
-
-    # - <<: *x-linux-38-shard
-    #   name: TOXENV=vendor-check
-    #   script: ${TOX_CMD} -e vendor-check
-
-    # - <<: *x-linux-27-shard
-    #   name: TOXENV=py27
-    #   script: ${TOX_CMD} -e py27
-
-    # - <<: *x-linux-27-shard
-    #   name: TOXENV=py27-subprocess
-    #   script: ${TOX_CMD} -e py27-subprocess
-
-    # - <<: *x-linux-shard
-    #   name: TOXENV=py35
-    #   python: 3.5.9
-    #   script: ${TOX_CMD} -e py35
-
-    # - <<: *x-linux-shard
-    #   name: TOXENV=py36
-    #   python: 3.6.10
-    #   script: ${TOX_CMD} -e py36
-
-    # - <<: *x-linux-shard
-    #   name: TOXENV=py37
-    #   python: 3.7.7
-    #   script: ${TOX_CMD} -e py37
-
-    # - <<: *x-linux-38-shard
-    #   name: TOXENV=py38
-    #   script: ${TOX_CMD} -e py38
-
-    # - <<: *x-linux-39-shard
-    #   name: TOXENV=py39
-    #   script: ${TOX_CMD} -e py39
-
-    # - <<: *x-linux-pypy-shard
-    #   name: TOXENV=pypy
-    #   script: ${TOX_CMD} -e pypy
-
-    # - <<: *x-linux-27-shard
-    #   name: TOXENV=py27-integration
-    #   script: ${TOX_CMD} -e py27-integration
-
-    # - <<: *x-linux-39-shard
-    #   name: TOXENV=py39-integration
-    #   script: ${TOX_CMD} -e py39-integration
-
-    # - <<: *x-linux-pypy-shard
-    #   name: TOXENV=pypy-integration
-    #   script: ${TOX_CMD} -e pypy-integration
-
-    # - <<: *x-osx-27-shard
-    #   name: TOXENV=py27
-    #   script: ${TOX_CMD} -e py27
-
-    # - <<: *x-osx-39-shard
-    #   name: TOXENV=py39
-    #   script: ${TOX_CMD} -e py39
-
-    # - <<: *x-osx-27-shard
-    #   name: TOXENV=py27-integration
-    #   script: ${TOX_CMD} -e py27-integration
-
-    # - <<: *x-osx-39-shard
-    #   name: TOXENV=py39-integration
-    #   script: ${TOX_CMD} -e py39-integration
+    - <<: *x-linux-shard
+      name: TOXENV=format-check
+      script: ${TOX_CMD} -e format-check
+
+    - <<: *x-linux-shard
+      name: TOXENV=typecheck
+      script: ${TOX_CMD} -e typecheck
+
+    - <<: *x-linux-38-shard
+      name: TOXENV=vendor-check
+      script: ${TOX_CMD} -e vendor-check
+
+    - <<: *x-linux-27-shard
+      name: TOXENV=py27
+      script: ${TOX_CMD} -e py27
+
+    - <<: *x-linux-27-shard
+      name: TOXENV=py27-subprocess
+      script: ${TOX_CMD} -e py27-subprocess
+
+    - <<: *x-linux-shard
+      name: TOXENV=py35
+      python: 3.5.9
+      script: ${TOX_CMD} -e py35
+
+    - <<: *x-linux-shard
+      name: TOXENV=py36
+      python: 3.6.10
+      script: ${TOX_CMD} -e py36
+
+    - <<: *x-linux-shard
+      name: TOXENV=py37
+      python: 3.7.7
+      script: ${TOX_CMD} -e py37
+
+    - <<: *x-linux-38-shard
+      name: TOXENV=py38
+      script: ${TOX_CMD} -e py38
+
+    - <<: *x-linux-39-shard
+      name: TOXENV=py39
+      script: ${TOX_CMD} -e py39
+
+    - <<: *x-linux-pypy-shard
+      name: TOXENV=pypy
+      script: ${TOX_CMD} -e pypy
+
+    - <<: *x-linux-27-shard
+      name: TOXENV=py27-integration
+      script: ${TOX_CMD} -e py27-integration
+
+    - <<: *x-linux-39-shard
+      name: TOXENV=py39-integration
+      script: ${TOX_CMD} -e py39-integration
+
+    - <<: *x-linux-pypy-shard
+      name: TOXENV=pypy-integration
+      script: ${TOX_CMD} -e pypy-integration
+
+    - <<: *x-osx-27-shard
+      name: TOXENV=py27
+      script: ${TOX_CMD} -e py27
+
+    - <<: *x-osx-39-shard
+      name: TOXENV=py39
+      script: ${TOX_CMD} -e py39
+
+    - <<: *x-osx-27-shard
+      name: TOXENV=py27-integration
+      script: ${TOX_CMD} -e py27-integration
+
+    - <<: *x-osx-39-shard
+      name: TOXENV=py39-integration
+      script: ${TOX_CMD} -e py39-integration
 
     - <<: *x-windows-27-shard
       name: TOXENV=py27