Add support for ObjC property name to be a single acronym.

Summary:
This change will support cases like:

```
@Property(assign, nonatomic) int ID;
```

Reviewers: benhamilton, hokein

Reviewed By: benhamilton

Subscribers: klimek, cfe-commits

Tags: #clang-tools-extra

Differential Revision: https://reviews.llvm.org/D46374

llvm-svn: 331545

clang-tools-extra/clang-tidy/objc/PropertyDeclarationCheck.cpp

@@ -217,6 +217,12 @@ void PropertyDeclarationCheck::check(const MatchFinder::MatchResult &Result) {
   assert(MatchedDecl->getName().size() > 0);
   auto *DeclContext = MatchedDecl->getDeclContext();
   auto *CategoryDecl = llvm::dyn_cast<ObjCCategoryDecl>(DeclContext);
+
+  auto AcronymsRegex =
+      llvm::Regex("^" + AcronymsGroupRegex(EscapedAcronyms) + "$");
+  if (AcronymsRegex.match(MatchedDecl->getName())) {
+    return;
+  }
   if (CategoryDecl != nullptr &&
       hasCategoryPropertyPrefix(MatchedDecl->getName())) {
     if (!prefixedPropertyNameValid(MatchedDecl->getName(), EscapedAcronyms) ||

clang-tools-extra/test/clang-tidy/objc-property-declaration-custom.m

@@ -14,4 +14,5 @@ @interface Foo
 // CHECK-MESSAGES: :[[@LINE-1]]:40: warning: property name 'ABC_custom_prefix' not using lowerCamelCase style or not prefixed in a category, according to the Apple Coding Guidelines [objc-property-declaration]
 @property(assign, nonatomic) int GIFIgnoreStandardAcronym;
 // CHECK-MESSAGES: :[[@LINE-1]]:34: warning: property name 'GIFIgnoreStandardAcronym' not using lowerCamelCase style or not prefixed in a category, according to the Apple Coding Guidelines [objc-property-declaration]
+@property(strong, nonatomic) NSString *TGIF;
 @end

clang-tools-extra/test/clang-tidy/objc-property-declaration.m

@@ -21,6 +21,7 @@ @interface Foo
 @property(assign, nonatomic) int enable2GBackgroundFetch;
 @property(assign, nonatomic) int shouldUseCFPreferences;
 @property(assign, nonatomic) int enableGLAcceleration;
+@property(assign, nonatomic) int ID;
 @end
 
 @interface Foo (Bar)