[clang] clang-format: Sort includes by stem rather than full filename (PR #137840)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang-format

Author: Daan De Meyer (DaanDeMeyer)

<details>
<summary>Changes</summary>

Sorting by stem gives nicer results when various header file names are substrings of other header file names, for example, a CLI application with a main header named analyze.h and a analyze-xxx.h header for each subcommand currently will always put analyze.h last after all the analyze-xxx.h headers, but putting analyze.h first instead of last is arguable nicer to read.

TLDR; Instead of

```
#include "analyze-blame.h"
#include "analyze.h"
```

We'll now get

```
#include "analyze.h"
#include "analyze-blame.h"
```

---
Full diff: https://github.com/llvm/llvm-project/pull/137840.diff


1 Files Affected:

- (modified) clang/lib/Format/Format.cpp (+10-8) 


``````````diff
diff --git a/clang/lib/Format/Format.cpp b/clang/lib/Format/Format.cpp
index 5a1c3f556b331..bc1e681c9be78 100644
--- a/clang/lib/Format/Format.cpp
+++ b/clang/lib/Format/Format.cpp
@@ -3219,17 +3219,19 @@ static void sortCppIncludes(const FormatStyle &Style,
 
   if (Style.SortIncludes == FormatStyle::SI_CaseInsensitive) {
     stable_sort(Indices, [&](unsigned LHSI, unsigned RHSI) {
-      const auto LHSFilenameLower = Includes[LHSI].Filename.lower();
-      const auto RHSFilenameLower = Includes[RHSI].Filename.lower();
-      return std::tie(Includes[LHSI].Priority, LHSFilenameLower,
-                      Includes[LHSI].Filename) <
-             std::tie(Includes[RHSI].Priority, RHSFilenameLower,
-                      Includes[RHSI].Filename);
+      const auto LHSStem = llvm::sys::path::stem(Includes[LHSI].Filename);
+      const auto RHSStem = llvm::sys::path::stem(Includes[RHSI].Filename);
+      const auto LHSStemLower = LHSStem.lower();
+      const auto RHSStemLower = RHSStem.lower();
+      return std::tie(Includes[LHSI].Priority, LHSStemLower, LHSStem) <
+             std::tie(Includes[RHSI].Priority, RHSStemLower, RHSStem);
     });
   } else {
     stable_sort(Indices, [&](unsigned LHSI, unsigned RHSI) {
-      return std::tie(Includes[LHSI].Priority, Includes[LHSI].Filename) <
-             std::tie(Includes[RHSI].Priority, Includes[RHSI].Filename);
+      const auto LHSStem = llvm::sys::path::stem(Includes[LHSI].Filename);
+      const auto RHSStem = llvm::sys::path::stem(Includes[RHSI].Filename);
+      return std::tie(Includes[LHSI].Priority, LHSStem) <
+             std::tie(Includes[RHSI].Priority, RHSStem);
     });
   }
 

``````````

</details>


https://github.com/llvm/llvm-project/pull/137840