[clang-tidy] readability-inconsistent-declaration-parameter-name: accept approximate name matches.

Summary:
The goal is to reduce false positives when the difference is intentional, like:

foo(StringRef name);
foo(StringRef name_ref) {
  string name = cleanup(name_ref);
  ...
}

Or semantically unimportant, like:
foo(StringRef full_name);
foo(StringRef name) { ... }

There are other matching names we won't recognise (e.g. syns vs synonyms) but
this catches many that we see in practice, and gives people a systematic
workaround.

The old behavior is available as a 'Strict' option.

Subscribers: xazax.hun, cfe-commits

Differential Revision: https://reviews.llvm.org/D49285

git-svn-id: https://llvm.org/svn/llvm-project/clang-tools-extra/trunk@336992 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 22 insertions, 10 deletions

diff --git a/clang-tidy/readability/InconsistentDeclarationParameterNameCheck.cpp b/clang-tidy/readability/InconsistentDeclarationParameterNameCheck.cpp
index 254ef960..f1d0036c 100644
--- a/clang-tidy/readability/InconsistentDeclarationParameterNameCheck.cpp
+++ b/clang-tidy/readability/InconsistentDeclarationParameterNameCheck.cpp
@@ -90,10 +90,20 @@ bool checkIfFixItHintIsApplicable(
   return true;
 }
 
+bool nameMatch(StringRef L, StringRef R, bool Strict) {
+  if (Strict)
+    return L.empty() || R.empty() || L == R;
+  // We allow two names if one is a prefix/suffix of the other, ignoring case.
+  // Important special case: this is true if either parameter has no name!
+  return L.startswith_lower(R) || R.startswith_lower(L) ||
+         L.endswith_lower(R) || R.endswith_lower(L);
+}
+
 DifferingParamsContainer
 findDifferingParamsInDeclaration(const FunctionDecl *ParameterSourceDeclaration,
                                  const FunctionDecl *OtherDeclaration,
-                                 const FunctionDecl *OriginalDeclaration) {
+                                 const FunctionDecl *OriginalDeclaration,
+                                 bool Strict) {
   DifferingParamsContainer DifferingParams;
 
   auto SourceParamIt = ParameterSourceDeclaration->param_begin();
@@ -106,8 +116,7 @@ findDifferingParamsInDeclaration(const FunctionDecl *ParameterSourceDeclaration,
 
     // FIXME: Provide a way to extract commented out parameter name from comment
     // next to it.
-    if (!SourceParamName.empty() && !OtherParamName.empty() &&
-        SourceParamName != OtherParamName) {
+    if (!nameMatch(SourceParamName, OtherParamName, Strict)) {
       SourceRange OtherParamNameRange =
           DeclarationNameInfo((*OtherParamIt)->getDeclName(),
                               (*OtherParamIt)->getLocation())
@@ -128,9 +137,9 @@ findDifferingParamsInDeclaration(const FunctionDecl *ParameterSourceDeclaration,
 }
 
 InconsistentDeclarationsContainer
-findInconsitentDeclarations(const FunctionDecl *OriginalDeclaration,
+findInconsistentDeclarations(const FunctionDecl *OriginalDeclaration,
                             const FunctionDecl *ParameterSourceDeclaration,
-                            SourceManager &SM) {
+                            SourceManager &SM, bool Strict) {
   InconsistentDeclarationsContainer InconsistentDeclarations;
   SourceLocation ParameterSourceLocation =
       ParameterSourceDeclaration->getLocation();
@@ -141,7 +150,7 @@ findInconsitentDeclarations(const FunctionDecl *OriginalDeclaration,
       DifferingParamsContainer DifferingParams =
           findDifferingParamsInDeclaration(ParameterSourceDeclaration,
                                            OtherDeclaration,
-                                           OriginalDeclaration);
+                                           OriginalDeclaration, Strict);
       if (!DifferingParams.empty()) {
         InconsistentDeclarations.emplace_back(OtherDeclaration->getLocation(),
                                               std::move(DifferingParams));
@@ -284,6 +293,7 @@ void formatDiagnostics(
 void InconsistentDeclarationParameterNameCheck::storeOptions(
     ClangTidyOptions::OptionMap &Opts) {
   Options.store(Opts, "IgnoreMacros", IgnoreMacros);
+  Options.store(Opts, "Strict", Strict);
 }
 
 void InconsistentDeclarationParameterNameCheck::registerMatchers(
@@ -305,9 +315,9 @@ void InconsistentDeclarationParameterNameCheck::check(
       getParameterSourceDeclaration(OriginalDeclaration);
 
   InconsistentDeclarationsContainer InconsistentDeclarations =
-      findInconsitentDeclarations(OriginalDeclaration,
-                                  ParameterSourceDeclaration,
-                                  *Result.SourceManager);
+      findInconsistentDeclarations(OriginalDeclaration,
+                                   ParameterSourceDeclaration,
+                                   *Result.SourceManager, Strict);
   if (InconsistentDeclarations.empty()) {
     // Avoid unnecessary further visits.
     markRedeclarationsAsVisited(OriginalDeclaration);
diff --git a/clang-tidy/readability/InconsistentDeclarationParameterNameCheck.h b/clang-tidy/readability/InconsistentDeclarationParameterNameCheck.h
index a6e0dfc4..602856fa 100644
--- a/clang-tidy/readability/InconsistentDeclarationParameterNameCheck.h
+++ b/clang-tidy/readability/InconsistentDeclarationParameterNameCheck.h
@@ -28,7 +28,8 @@ public:
   InconsistentDeclarationParameterNameCheck(StringRef Name,
                                             ClangTidyContext *Context)
       : ClangTidyCheck(Name, Context),
-        IgnoreMacros(Options.getLocalOrGlobal("IgnoreMacros", 1) != 0) {}
+        IgnoreMacros(Options.getLocalOrGlobal("IgnoreMacros", 1) != 0),
+        Strict(Options.getLocalOrGlobal("Strict", 0) != 0) {}
 
   void storeOptions(ClangTidyOptions::OptionMap &Opts) override;
   void registerMatchers(ast_matchers::MatchFinder *Finder) override;
@@ -39,6 +40,7 @@ private:
 
   llvm::DenseSet<const FunctionDecl *> VisitedDeclarations;
   const bool IgnoreMacros;
+  const bool Strict;
 };
 
 } // namespace readability