From f784d39b50b36ca06fbe844e2b09cbd996747577 Mon Sep 17 00:00:00 2001
From: Lorenz Brun <lorenz@monogon.tech>
Date: Thu, 31 Aug 2023 15:52:06 +0200
Subject: [PATCH] Add support for prepatching

---
 internal/bzlmod/go_deps.bzl |  8 ++++++++
 internal/go_repository.bzl  | 10 ++++++++++
 2 files changed, 18 insertions(+)

diff --git a/internal/bzlmod/go_deps.bzl b/internal/bzlmod/go_deps.bzl
index e304ec5..7684243 100644
--- a/internal/bzlmod/go_deps.bzl
+++ b/internal/bzlmod/go_deps.bzl
@@ -156,6 +156,9 @@ 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 []
@@ -605,6 +608,7 @@ 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,
@@ -616,6 +620,7 @@ 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),
             })
@@ -799,6 +804,9 @@ _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 627a1f9..4da270f 100644
--- a/internal/go_repository.bzl
+++ b/internal/go_repository.bzl
@@ -296,6 +296,11 @@ 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 = ""
@@ -583,6 +588,11 @@ go_repository = repository_rule(
             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