fix(local-toolchains): don't watch non-existent include directory (bazel-contrib#3048)

Apparently, Macs can mis-report their include directory.

Since includes are only needed if C extensions are built, skip watching
the directory
if it doesn't exist.

Work around for
bazel-contrib#3043

---------

Co-authored-by: google-labs-jules[bot] <161369871+google-labs-jules[bot]@users.noreply.github.com>
Co-authored-by: Ignas Anikevicius <[email protected]>
(cherry picked from commit be55942)

Author: 3 people

CHANGELOG.md

@@ -47,6 +47,17 @@ BEGIN_UNRELEASED_TEMPLATE
 END_UNRELEASED_TEMPLATE
 -->
 
+{#1-5-3}
+## [1.5.3] - 2025-08-11
+
+[1.5.3]: https://github.com/bazel-contrib/rules_python/releases/tag/1.5.3
+
+{#v1-5-3-fixed}
+### Fixed
+* (toolchains) `local_runtime_repo` now checks if the include directory exists
+  before attempting to watch it, fixing issues on macOS with system Python
+  ({gh-issue}`3043`).
+
 {#1-5-2}
 ## [1.5.2] - 2025-08-11
 
@@ -65,6 +76,7 @@ END_UNRELEASED_TEMPLATE
 * (core) builds work again on `7.x` `WORKSPACE` configurations
   ([#3119](https://github.com/bazel-contrib/rules_python/issues/3119)).
 
+
 {#1-5-1}
 ## [1.5.1] - 2025-07-06
 

python/private/local_runtime_repo.bzl

@@ -99,7 +99,15 @@ def _local_runtime_repo_impl(rctx):
     interpreter_path = info["base_executable"]
 
     # NOTE: Keep in sync with recursive glob in define_local_runtime_toolchain_impl
-    repo_utils.watch_tree(rctx, rctx.path(info["include"]))
+    include_path = rctx.path(info["include"])
+
+    # The reported include path may not exist, and watching a non-existant
+    # path is an error. Silently skip, since includes are only necessary
+    # if C extensions are built.
+    if include_path.exists and include_path.is_dir:
+        repo_utils.watch_tree(rctx, include_path)
+    else:
+        pass
 
     # The cc_library.includes values have to be non-absolute paths, otherwise
     # the toolchain will give an error. Work around this error by making them