From 6d876e488124d7f0f6d660164c112a1a5d375218 Mon Sep 17 00:00:00 2001
From: Tim Windelschmidt <tim@monogon.tech>
Date: Wed, 17 Jul 2024 18:27:41 +0200
Subject: [PATCH] Add support for prepatching

---
 internal/bzlmod/go_deps.bzl | 13 +++++++++++++
 internal/go_repository.bzl  | 10 +++++++++-
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/internal/bzlmod/go_deps.bzl b/internal/bzlmod/go_deps.bzl
index dcd0db3..7170506 100644
--- a/internal/bzlmod/go_deps.bzl
+++ b/internal/bzlmod/go_deps.bzl
@@ -159,6 +159,9 @@ def _get_build_extra_args(path, gazelle_overrides, gazelle_default_attributes):
 def _get_patches(path, module_overrides):
     return _get_override_or_default(module_overrides, struct(), {}, path, [], "patches")

+def _get_pre_patches(path, module_overrides):
+    return _get_override_or_default(module_overrides, struct(), {}, path, [], "pre_patches")
+
 def _get_patch_args(path, module_overrides):
     override = _get_override_or_default(module_overrides, struct(), {}, path, None, "patch_strip")
     return ["-p{}".format(override)] if override else []
@@ -235,6 +238,7 @@ def _process_gazelle_override(gazelle_override_tag):
 def _process_module_override(module_override_tag):
     return struct(
         patches = module_override_tag.patches,
+        pre_patches = module_override_tag.pre_patches,
         patch_strip = module_override_tag.patch_strip,
     )

@@ -243,6 +247,7 @@ def _process_archive_override(archive_override_tag):
         urls = archive_override_tag.urls,
         sha256 = archive_override_tag.sha256,
         strip_prefix = archive_override_tag.strip_prefix,
+        pre_patches = archive_override_tag.pre_patches,
         patches = archive_override_tag.patches,
         patch_strip = archive_override_tag.patch_strip,
     )
@@ -611,6 +616,7 @@ def _go_deps_impl(module_ctx):
             "build_directives": _get_directives(path, gazelle_overrides, gazelle_default_attributes),
             "build_file_generation": _get_build_file_generation(path, gazelle_overrides, gazelle_default_attributes),
             "build_extra_args": _get_build_extra_args(path, gazelle_overrides, gazelle_default_attributes),
+            "pre_patches": _get_pre_patches(path, module_overrides),
             "patches": _get_patches(path, module_overrides),
             "patch_args": _get_patch_args(path, module_overrides),
             "debug_mode": debug_mode,
@@ -622,6 +628,7 @@ def _go_deps_impl(module_ctx):
                 "urls": archive_override.urls,
                 "strip_prefix": archive_override.strip_prefix,
                 "sha256": archive_override.sha256,
+                "pre_patches": _get_pre_patches(path, archive_overrides),
                 "patches": _get_patches(path, archive_overrides),
                 "patch_args": _get_patch_args(path, archive_overrides),
             })
@@ -775,6 +782,9 @@ _archive_override_tag = tag_class(
             SHA-256 sum of the downloaded archive. When set, Bazel will verify the archive
             against this sum before extracting it.""",
         ),
+        "pre_patches": attr.label_list(
+            doc = "A list of patches to apply to the repository before gazelle runs.",
+        ),
         "patches": attr.label_list(
             doc = "A list of patches to apply to the repository *after* gazelle runs.",
         ),
@@ -813,6 +823,9 @@ _module_override_tag = tag_class(
             extension within this Bazel module.""",
             mandatory = True,
         ),
+        "pre_patches": attr.label_list(
+            doc = "A list of patches to apply to the repository before gazelle runs.",
+        ),
         "patches": attr.label_list(
             doc = "A list of patches to apply to the repository *after* gazelle runs.",
         ),
diff --git a/internal/go_repository.bzl b/internal/go_repository.bzl
index 48a9d14..e3efa5b 100644
--- a/internal/go_repository.bzl
+++ b/internal/go_repository.bzl
@@ -286,6 +286,11 @@ def _go_repository_impl(ctx):
     if result.return_code:
         fail("%s: %s" % (ctx.name, result.stderr))

+    # TODO(lorenz): Replace this with patch() once the patches argument no longer gets merged with
+    # the attribute pulled from ctx.
+    for p in ctx.attr.pre_patches:
+        ctx.patch(p, 1)
+
     # Repositories are fetched. Determine if build file generation is needed.
     build_file_names = ctx.attr.build_file_name.split(",")
     existing_build_file = ""
@@ -623,7 +628,10 @@ go_repository = repository_rule(
             prefixed with `#` automatically. A common use case is to pass a list of
             Gazelle directives.""",
         ),
-
+        # Patches to apply before running gazelle.
+        "pre_patches": attr.label_list(
+            doc = "A list of patches to apply to the repository before gazelle runs.",
+        ),
         # Patches to apply after running gazelle.
         "patches": attr.label_list(
             doc = "A list of patches to apply to the repository after gazelle runs.",
--
2.44.1