From e3cac314cef8495d588ad4dcc743fe1c0aea8965 Mon Sep 17 00:00:00 2001
From: Johan Nilsson <johan.nilsson.10@volvocars.com>
Date: Mon, 9 Dec 2024 15:23:16 +0100
Subject: [PATCH] fix: Add option to skip target without srcs

Add option 'skip_if_no_srcs' to lint_clang_tidy aspect
Set to True to skip target if it provides CcInfo but has no source files. By default this will generate an error.
---
 docs/clang-tidy.md  |  3 ++-
 lint/clang_tidy.bzl | 13 ++++++++++---
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/docs/clang-tidy.md b/docs/clang-tidy.md
index 993b40f9..5f1658fd 100644
--- a/docs/clang-tidy.md
+++ b/docs/clang-tidy.md
@@ -122,7 +122,7 @@ is_parent_in_list(<a href="#is_parent_in_list-dir">dir</a>, <a href="#is_parent_
 load("@aspect_rules_lint//lint:clang_tidy.bzl", "lint_clang_tidy_aspect")
 
 lint_clang_tidy_aspect(<a href="#lint_clang_tidy_aspect-binary">binary</a>, <a href="#lint_clang_tidy_aspect-configs">configs</a>, <a href="#lint_clang_tidy_aspect-global_config">global_config</a>, <a href="#lint_clang_tidy_aspect-header_filter">header_filter</a>, <a href="#lint_clang_tidy_aspect-lint_target_headers">lint_target_headers</a>,
-                       <a href="#lint_clang_tidy_aspect-angle_includes_are_system">angle_includes_are_system</a>, <a href="#lint_clang_tidy_aspect-verbose">verbose</a>)
+                       <a href="#lint_clang_tidy_aspect-angle_includes_are_system">angle_includes_are_system</a>, <a href="#lint_clang_tidy_aspect-skip_if_no_srcs">skip_if_no_srcs</a>, <a href="#lint_clang_tidy_aspect-verbose">verbose</a>)
 </pre>
 
 A factory function to create a linter aspect.
@@ -138,6 +138,7 @@ A factory function to create a linter aspect.
 | <a id="lint_clang_tidy_aspect-header_filter"></a>header_filter |  optional, set to a posix regex to supply to clang-tidy with the -header-filter option   |  `""` |
 | <a id="lint_clang_tidy_aspect-lint_target_headers"></a>lint_target_headers |  optional, set to True to pass a pattern that includes all headers with the target's directory prefix. This crude control may include headers from the linted target in the results. If supplied, overrides the header_filter option.   |  `False` |
 | <a id="lint_clang_tidy_aspect-angle_includes_are_system"></a>angle_includes_are_system |  controls how angle includes are passed to clang-tidy. By default, Bazel passes these as -isystem. Change this to False to pass these as -I, which allows clang-tidy to regard them as regular header files.   |  `True` |
+| <a id="lint_clang_tidy_aspect-skip_if_no_srcs"></a>skip_if_no_srcs |  optional, set to True to skip target if it provides CcInfo but has no source files. By default this will generate an error.   |  `False` |
 | <a id="lint_clang_tidy_aspect-verbose"></a>verbose |  print debug messages including clang-tidy command lines being invoked.   |  `False` |
 
 
diff --git a/lint/clang_tidy.bzl b/lint/clang_tidy.bzl
index 0c78aa47..e8ec5664 100644
--- a/lint/clang_tidy.bzl
+++ b/lint/clang_tidy.bzl
@@ -177,10 +177,12 @@ def _is_source(file):
     return (file.is_source and file.extension in permitted_source_types)
 
 # modification of filter_srcs in lint_aspect.bzl that filters out header files
-def _filter_srcs(rule):
+def _filter_srcs(rule, skip_if_no_srcs = False):
     if "lint-genfiles" in rule.attr.tags:
         return rule.files.srcs
     else:
+        if skip_if_no_srcs and not hasattr(rule.files, "srcs"):
+            return []
         return [s for s in rule.files.srcs if _is_source(s)]
 
 def is_parent_in_list(dir, list):
@@ -369,7 +371,7 @@ def _clang_tidy_aspect_impl(target, ctx):
     if not CcInfo in target:
         return []
 
-    files_to_lint = _filter_srcs(ctx.rule)
+    files_to_lint = _filter_srcs(ctx.rule, ctx.attr._skip_if_no_srcs)
     compilation_context = target[CcInfo].compilation_context
     if hasattr(ctx.rule.attr, "implementation_deps"):
         compilation_context = cc_common.merge_compilation_contexts(
@@ -394,7 +396,7 @@ def _clang_tidy_aspect_impl(target, ctx):
     clang_tidy_action(ctx, compilation_context, ctx.executable, files_to_lint, outputs.machine.out, outputs.machine.exit_code)
     return [info]
 
-def lint_clang_tidy_aspect(binary, configs = [], global_config = [], header_filter = "", lint_target_headers = False, angle_includes_are_system = True, verbose = False):
+def lint_clang_tidy_aspect(binary, configs = [], global_config = [], header_filter = "", lint_target_headers = False, angle_includes_are_system = True, skip_if_no_srcs = False, verbose = False):
     """A factory function to create a linter aspect.
 
     Args:
@@ -419,6 +421,8 @@ def lint_clang_tidy_aspect(binary, configs = [], global_config = [], header_filt
         angle_includes_are_system: controls how angle includes are passed to clang-tidy. By default, Bazel
             passes these as -isystem. Change this to False to pass these as -I, which allows clang-tidy to regard
             them as regular header files.
+        skip_if_no_srcs: optional, set to True to skip target if it provides CcInfo but has no source files. By
+            default this will generate an error.
         verbose: print debug messages including clang-tidy command lines being invoked.
     """
 
@@ -449,6 +453,9 @@ def lint_clang_tidy_aspect(binary, configs = [], global_config = [], header_filt
             "_angle_includes_are_system": attr.bool(
                 default = angle_includes_are_system,
             ),
+            "_skip_if_no_srcs": attr.bool(
+                default = skip_if_no_srcs,
+            ),
             "_verbose": attr.bool(
                 default = verbose,
             ),