Watch patch files

Author: erenon

crate_universe/extensions.bzl

@@ -992,6 +992,13 @@ def _crate_impl(module_ctx):
         repo_specific_annotations = {}
         for annotation_tag in mod.tags.annotation:
             annotation_dict = structs.to_dict(annotation_tag)
+
+            # Watch patch files so changes trigger repository re-generation.
+            # This must be done before patches are stringified downstream.
+            for patch_label in annotation_dict.get("patches", []):
+                if patch_label:
+                    module_ctx.watch(module_ctx.path(patch_label))
+
             if "build_script_data_select" in annotation_dict:
                 annotation_dict["build_script_data"] = struct(
                     common = annotation_dict["build_script_data"],

crate_universe/private/generate_utils.bzl

@@ -289,6 +289,14 @@ def compile_config(
     if unexpected:
         fail("The following annotations use `additive_build_file` which is not supported for {}: {}".format(repository_name, unexpected))
 
+    # Watch patch files so changes trigger repository re-generation.
+    if repository_ctx:
+        for _name, data in annotations.items():
+            patches = data.get("patches", None)
+            if patches:
+                for patch in patches:
+                    repository_ctx.watch(repository_ctx.path(Label(patch)))
+
     # Deprecated: Apply `generate_target_compatible_with` to `render_config`.
     if not generate_target_compatible_with:
         # buildifier: disable=print