feat!: make windows use venvs

.bazelrc

@@ -42,6 +42,7 @@ common --enable_bzlmod
 # Local disk cache greatly speeds up builds if the regular cache is lost
 common --disk_cache=~/.cache/bazel/bazel-disk-cache
 
+
 # Additional config to use for readthedocs builds.
 # See .readthedocs.yml for additional flags that can only be determined from
 # the runtime environment.
@@ -54,3 +55,6 @@ common --incompatible_no_implicit_file_export
 
 build --lockfile_mode=update
 
+import %workspace%/.bazelrc.specialized_configs
+
+try-import user.bazelrc

.bazelrc.specialized_configs

@@ -0,0 +1,12 @@
+
+# Helper config to run most tests without waiting an inordinate amount
+# of time or freezing the system
+common:fast-tests --build_tests_only=true
+common:fast-tests --build_tag_filters=-large,-enormous,-integration-test
+common:fast-tests --test_tag_filters=-large,-enormous,-integration-test
+
+# Helper config for running a single test locally and investigating resulting state
+common:testone --test_output=streamed
+common:testone --test_strategy=standalone
+common:testone --spawn_strategy=standalone
+common:testone --strategy=standalone

python/private/hermetic_runtime_repo_setup.bzl

@@ -240,6 +240,18 @@ def define_hermetic_runtime_toolchain_impl(
             _IS_FREETHREADED_YES: "cpython-{major}{minor}t".format(**version_dict),
             _IS_FREETHREADED_NO: "cpython-{major}{minor}".format(**version_dict),
         }),
+        # On Windows, a symlink-style venv requires supporting .dll files.
+        venv_bin_files = select({
+            "@platforms//os:windows": native.glob(
+                include = [
+                    "*.dll",
+                ],
+                # This must be true because glob empty-ness is checked
+                # during loading phase, before select() filters it out.
+                allow_empty = True,
+            ),
+            "//conditions:default": [],
+        }),
     )
 
     py_runtime_pair(

python/private/local_runtime_repo.bzl

@@ -74,19 +74,19 @@ def _norm_path(path):
 def _symlink_libraries(rctx, logger, libraries, shlib_suffix):
     """Symlinks the shared libraries into the lib/ directory.
 
+    Individual files are symlinked instead of the whole directory because
+    shared_lib_dirs contains multiple search paths for the shared libraries,
+    and the python files may be missing from any of those directories, and
+    any of those directories may include non-python runtime libraries,
+    as would be the case if LIBDIR were, for example, /usr/lib.
+
     Args:
         rctx: A repository_ctx object
         logger: A repo_utils.logger object
         libraries: paths to libraries to attempt to symlink.
         shlib_suffix: Optional. Ensure that the generated symlinks end with this suffix.
     Returns:
         A list of library paths (under lib/) linked by the action.
-
-    Individual files are symlinked instead of the whole directory because
-    shared_lib_dirs contains multiple search paths for the shared libraries,
-    and the python files may be missing from any of those directories, and
-    any of those directories may include non-python runtime libraries,
-    as would be the case if LIBDIR were, for example, /usr/lib.
     """
     result = []
     for source in libraries:

python/private/local_runtime_repo_setup.bzl

@@ -153,6 +153,19 @@ def define_local_runtime_toolchain_impl(
         implementation_name = implementation_name,
         abi_flags = abi_flags,
         pyc_tag = "{}-{}{}{}".format(implementation_name, major, minor, abi_flags),
+        venv_bin_files = select({
+            "@platforms//os:windows": native.glob(
+                include = [
+                    "lib/*.dll",
+                    # The pdb files just provide debugging information
+                    "lib/*.pdb",
+                ],
+                # This must be true because glob empty-ness is checked
+                # during loading phase, before select() filters it out.
+                allow_empty = True,
+            ),
+            "//conditions:default": [],
+        }),
     )
 
     py_runtime_pair(