From a054c0464361b2829f905a5d45b6ce739cf33c40 Mon Sep 17 00:00:00 2001
From: Henner Zeller <h.zeller@acm.org>
Date: Sat, 31 Aug 2024 09:30:55 -0700
Subject: [PATCH] dwyu: Make sure includes in toplevel libraries are correctly
 recognized.

---
 bant/tool/dwyu.cc      |  3 ++-
 bant/tool/dwyu_test.cc | 20 ++++++++++++++++++++
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/bant/tool/dwyu.cc b/bant/tool/dwyu.cc
index 2fead28..f7df515 100644
--- a/bant/tool/dwyu.cc
+++ b/bant/tool/dwyu.cc
@@ -70,7 +70,8 @@ bool IsHeaderInList(std::string_view header,
   // so we always need to prepend that prefix_path.
   for (const std::string_view list_item : list) {
     if (header.ends_with(list_item) &&  // cheap first test before strcat
-        absl::StrCat(prefix_path, "/", list_item) == header) {
+        (header == list_item ||
+         absl::StrCat(prefix_path, "/", list_item) == header)) {
       return true;
     }
   }
diff --git a/bant/tool/dwyu_test.cc b/bant/tool/dwyu_test.cc
index 212b0fe..320aa28 100644
--- a/bant/tool/dwyu_test.cc
+++ b/bant/tool/dwyu_test.cc
@@ -234,6 +234,26 @@ cc_library(
   }
 }
 
+TEST(DWYUTest, ToplevelIncludesWithoutPrefixSlashWork) {
+  ParsedProjectTestUtil pp;
+  pp.Add("//", R"(
+cc_library(
+  name = "foo",
+  srcs = ["foo.cc"],
+  hdrs = ["foo.h"]
+)
+)");
+
+  {
+    DWYUTestFixture tester(pp.project());
+    tester.AddSource("foo.h", "");
+    tester.AddSource("foo.cc", R"(
+#include "foo.h"
+)");
+    tester.RunForTarget("//:foo");
+  }
+}
+
 TEST(DWYUTest, ChooseMinimalDependencySetIfMultipleLibrariesProvideHeader) {
   ParsedProjectTestUtil pp;
   pp.Add("//path", R"(