[clang-format] Skip line splices when sorting C++ includes

[owenca]

Fixes #109864.

[llvmbot]

@llvm/pr-subscribers-clang-format

Author: Owen Pan (owenca)

Changes

Fixes #109864.

---

Full diff: https://github.com/llvm/llvm-project/pull/120680.diff

2 Files Affected:

• (modified) clang/lib/Format/Format.cpp (+8-1)
• (modified) clang/unittests/Format/SortIncludesTest.cpp (+12)

diff --git a/clang/lib/Format/Format.cpp b/clang/lib/Format/Format.cpp
index dcaac4b0d42cc5..f79f9cb1ecdd22 100644
--- a/clang/lib/Format/Format.cpp
+++ b/clang/lib/Format/Format.cpp
@@ -3247,7 +3247,14 @@ tooling::Replacements sortCppIncludes(const FormatStyle &Style, StringRef Code,
   std::string RawStringTermination = ")\"";
 
   for (;;) {
-    auto Pos = Code.find('\n', SearchFrom);
+    size_t Pos = SearchFrom;
+    if (Code[SearchFrom] != '\n') {
+      do { // Search for the first newline while skipping line splices.
+        ++Pos;
+        Pos = Code.find('\n', Pos);
+      } while (Pos != StringRef::npos && Code[Pos - 1] == '\\');
+    }
+
     StringRef Line =
         Code.substr(Prev, (Pos != StringRef::npos ? Pos : Code.size()) - Prev);
 
diff --git a/clang/unittests/Format/SortIncludesTest.cpp b/clang/unittests/Format/SortIncludesTest.cpp
index 31753825646373..cb3f8c73a04871 100644
--- a/clang/unittests/Format/SortIncludesTest.cpp
+++ b/clang/unittests/Format/SortIncludesTest.cpp
@@ -984,6 +984,18 @@ TEST_F(SortIncludesTest, SortAndDeduplicateIncludes) {
                     "#include <c>\n"
                     "#include <b>"));
 
+  verifyFormat("/* COPYRIGHT *\\\n"
+               "\\* (C) 2024  */\n"
+               "\n"
+               "#include <a>\n"
+               "#include <b>",
+               sort("/* COPYRIGHT *\\\n"
+                    "\\* (C) 2024  */\n"
+                    "\n"
+                    "#include <b>\n"
+                    "#include <a>\n"
+                    "#include <b>"));
+
   Style.IncludeBlocks = tooling::IncludeStyle::IBS_Merge;
   verifyFormat("#include <a>\n"
                "#include <b>\n"

[rymiel]

Why is the extra Size variable needed? Why can't it stay as for (;;) ?

[owenca]

Because it's used in SearchFrom < Size. My previous version using for (;;) caused a crash in ToolingTests.