escape redirection path in eden config toml on Windows

Summary:
S477425 happened because when we add a new redirection on windows, we didn't escape the backslashes on windows. (Look at the test plan before this change)
The root cause was in this fact that we didn't have any serialization for `redirection` and `redirection_targets` in `CheckoutConfig`
Then the file path save wrong in the toml file.
To fix this issue, we need to consider two things:
1- This diff adds a `serialize_path_map` serialization to both `redirection` and `redirection_targets`
2- Also, when we want to read path from the `config.toml` file, we should consider that all the \\ should convert to \ in addition to / to \
The changes on deserialized function consider these changes.
It is explained in the test plan that the redirect works fine and eden can successfully restart by these changes

Reviewed By: jdelliot

Differential Revision: D67293753

fbshipit-source-id: d27239c4d76d619a29e785bd4378d62b820216d5

eden/fs/cli_rs/edenfs-client/src/checkout.rs

@@ -39,6 +39,7 @@ use edenfs_utils::path_from_bytes;
 #[cfg(windows)]
 use edenfs_utils::strip_unc_prefix;
 use edenfs_utils::varint::decode_varint;
+use serde::ser::SerializeMap;
 use serde::Deserialize;
 use serde::Deserializer;
 use serde::Serialize;
@@ -311,12 +312,16 @@ struct PredictivePrefetch {
 pub struct CheckoutConfig {
     repository: Repository,
 
-    #[serde(deserialize_with = "deserialize_redirections")]
+    #[serde(
+        deserialize_with = "deserialize_redirections",
+        serialize_with = "serialize_path_map"
+    )]
     redirections: BTreeMap<PathBuf, RedirectionType>,
 
     #[serde(
         rename = "redirection-targets",
         deserialize_with = "deserialize_redirection_targets",
+        serialize_with = "serialize_path_map",
         default = "default_redirection_targets"
     )]
     redirection_targets: BTreeMap<PathBuf, PathBuf>,
@@ -332,6 +337,36 @@ fn default_redirection_targets() -> BTreeMap<PathBuf, PathBuf> {
     BTreeMap::new()
 }
 
+fn serialize_path_map<V, S>(map: &BTreeMap<PathBuf, V>, serializer: S) -> Result<S::Ok, S::Error>
+where
+    S: Serializer,
+    V: Serialize,
+{
+    let mut map_serializer = serializer.serialize_map(Some(map.len()))?;
+    for (key, value) in map {
+        let serialized_key = if cfg!(windows) {
+            // On Windows, we need to escape backslashes in the path, since
+            // TOML uses backslashes as an escape character.
+            // temp_key is used to make sure that the path is not already escaped
+            // from previous serialization, since we don't want to double-escape it.
+            let temp_key = key.display().to_string().replace("\\\\", "\\");
+            temp_key.replace('\\', "\\\\")
+        } else {
+            key.to_string_lossy().into_owned()
+        };
+        match map_serializer.serialize_entry(&serialized_key, value) {
+            Ok(_) => continue,
+            Err(e) => {
+                return Err(serde::ser::Error::custom(format!(
+                    "Unsupported redirection. Target must be string. Error: {}",
+                    e
+                )));
+            }
+        }
+    }
+    map_serializer.end()
+}
+
 fn deserialize_redirection_targets<'de, D>(
     deserializer: D,
 ) -> Result<BTreeMap<PathBuf, PathBuf>, D::Error>
@@ -346,7 +381,7 @@ where
                 PathBuf::from(
                     // Convert path separator to backslash on Windows
                     if cfg!(windows) {
-                        key.replace("/", "\\")
+                        key.replace("\\\\", "\\").replace('/', "\\")
                     } else {
                         key
                     },

eden/fs/cli_rs/edenfs-client/src/redirect.rs

@@ -1071,7 +1071,7 @@ where
                 PathBuf::from(
                     // Convert path separator to backslash on Windows
                     if cfg!(windows) {
-                        key.replace("/", "\\")
+                        key.replace("\\\\", "\\").replace('/', "\\")
                     } else {
                         key
                     },