From 745b5d3d4fd1d5cc97c84d559aa3dc25cc253b7f Mon Sep 17 00:00:00 2001
From: Jade Lovelace <lix@jade.fyi>
Date: Thu, 23 May 2024 15:16:10 -0700
Subject: [PATCH] clang-tidy: work with angle brackets and external projects

Also fix the readme

Change-Id: I422dff5536bf01d43983621aa01035bd77ac0252
---
 clang-tidy/FixIncludes.cc            | 43 +++++++++++++++++-----------
 clang-tidy/README.md                 |  8 +++---
 doc/manual/rl-next/rename-lixexpr.md |  4 +--
 3 files changed, 32 insertions(+), 23 deletions(-)

diff --git a/clang-tidy/FixIncludes.cc b/clang-tidy/FixIncludes.cc
index 8ba350243..602d3d355 100644
--- a/clang-tidy/FixIncludes.cc
+++ b/clang-tidy/FixIncludes.cc
@@ -44,32 +44,41 @@ void FixIncludesCallbacks::LexedFileChanged(FileID, LexedFileChangeReason,
 }
 
 void FixIncludesCallbacks::InclusionDirective(
-    SourceLocation, const Token &, StringRef, bool,
+    SourceLocation, const Token &, StringRef FileName, bool IsAngled,
     CharSourceRange FilenameRange, OptionalFileEntryRef File, StringRef,
     StringRef, const Module *, SrcMgr::CharacteristicKind) {
   if (Ignore)
     return;
 
   // FIXME: this is kinda evil, but this is a one-time fixup
-  const std::string SourceDir = "src/";
+  const std::vector<std::string> SourceDirs = {"src/", "include/lix/"};
 
-  if (File && File->getNameAsRequested().contains(SourceDir)) {
-    StringRef Name = File->getNameAsRequested();
-    auto Idx = Name.find(SourceDir);
-    assert(Idx != std::string::npos);
-    StringRef Suffix = Name.drop_front(Idx + SourceDir.length());
+  const auto Bracketize = [IsAngled](StringRef s) {
+    return IsAngled ? ("<" + s + ">").str() : ("\"" + s + "\"").str();
+  };
 
-    if (!Suffix.starts_with("lib")) {
-      llvm::dbgs() << "ignored: " << Suffix << "\n";
-      return;
+  for (const auto &SourceDir : SourceDirs) {
+    const bool IsAlreadyFixed = FileName.starts_with("lix/lib");
+    if (File && File->getNameAsRequested().contains(SourceDir) &&
+        !IsAlreadyFixed) {
+      StringRef Name = File->getNameAsRequested();
+      auto Idx = Name.find(SourceDir);
+      assert(Idx != std::string::npos);
+      std::string Suffix = Name.drop_front(Idx + SourceDir.length()).str();
+
+      if (!Suffix.starts_with("lib")) {
+        llvm::dbgs() << "ignored: " << Suffix << "\n";
+        return;
+      }
+
+      Suffix = "lix/" + Suffix;
+
+      auto Diag = Check.diag(FilenameRange.getBegin(),
+                             "include needs to specify the source subdir");
+
+      Diag << FilenameRange
+           << FixItHint::CreateReplacement(FilenameRange, Bracketize(Suffix));
     }
-
-    auto Diag = Check.diag(FilenameRange.getBegin(),
-                           "include needs to specify the source subdir");
-
-    Diag << FilenameRange
-         << FixItHint::CreateReplacement(FilenameRange,
-                                         ("\"" + Suffix + "\"").str());
   }
 }
 
diff --git a/clang-tidy/README.md b/clang-tidy/README.md
index cf46c71ec..c2d1cb258 100644
--- a/clang-tidy/README.md
+++ b/clang-tidy/README.md
@@ -1,6 +1,6 @@
-# Clang tidy lints for Nix
+# Clang tidy lints for Lix
 
-This is a skeleton of a clang-tidy lints library for Nix.
+This is a skeleton of a clang-tidy lints library for Lix.
 
 Currently there is one check (which is already obsolete as it has served its
 goal and is there as an example), `HasPrefixSuffixCheck`.
@@ -10,13 +10,13 @@ goal and is there as an example), `HasPrefixSuffixCheck`.
 One file:
 
 ```
-ninja -C build && clang-tidy --checks='-*,nix-*' --load=build/libnix-clang-tidy.so -p ../compile_commands.json --fix ../src/libcmd/installables.cc
+ninja -C build && clang-tidy --checks='-*,lix-*' --load=build/liblix-clang-tidy.so -p ../compile_commands.json -header-filter '\.\./src/.*\.h' --fix ../src/libcmd/installables.cc
 ```
 
 Several files, in parallel:
 
 ```
-ninja -C build && run-clang-tidy -checks='-*,nix-*' -load=build/libnix-clang-tidy.so -p .. -fix ../src | tee -a clang-tidy-result
+ninja -C build && run-clang-tidy -checks='-*,lix-*' -load=build/liblix-clang-tidy.so -p .. -header-filter '\.\./src/.*\.h' -fix ../src | tee -a clang-tidy-result
 ```
 
 ## Resources
diff --git a/doc/manual/rl-next/rename-lixexpr.md b/doc/manual/rl-next/rename-lixexpr.md
index 698553c7f..32e3cfd09 100644
--- a/doc/manual/rl-next/rename-lixexpr.md
+++ b/doc/manual/rl-next/rename-lixexpr.md
@@ -22,10 +22,10 @@ Migration path:
 To apply this migration automatically, remove all `<nix/>` from includes, so `#include <nix/expr.hh>` -> `#include <expr.hh>`.
 Then, the correct paths will be resolved from the tangled mess, and the clang-tidy automated fix will work.
 
-Then run the following for out of tree projects:
+Then run the following for out of tree projects (header filter is set to only fix instances in headers in `../src` relative to the compiler's working directory, as would be the case in nix-eval-jobs or other things built with meson, e.g.):
 
 ```console
 lix_root=$HOME/lix
 (cd $lix_root/clang-tidy && nix develop -c 'meson setup build && ninja -C build')
-run-clang-tidy -checks='-*,lix-fixincludes' -load=$lix_root/clang-tidy/build/liblix-clang-tidy.so -p build/ -fix src
+run-clang-tidy -checks='-*,lix-fixincludes' -load=$lix_root/clang-tidy/build/liblix-clang-tidy.so -p build/ -header-filter '\.\./src/.*\.h' -fix src
 ```