[PATCH] D115121: Add support for return values in bugprone-stringview-nullptr

[CJ Johnson via Phabricator via cfe-commits]

CJ-Johnson created this revision.
CJ-Johnson added a reviewer: ymandel.
Herald added a subscriber: carlosgalvezp.
CJ-Johnson requested review of this revision.
Herald added a project: clang-tools-extra.
Herald added a subscriber: cfe-commits.

bugprone-stringview-nullptr was not initially written with tests for return statements. After landing the check, the thought crossed my mind to add such tests. After writing them, I realized they needed additional handling in the matchers.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D115121

Files:
  clang-tools-extra/clang-tidy/bugprone/StringviewNullptrCheck.cpp
  clang-tools-extra/test/clang-tidy/checkers/bugprone-stringview-nullptr.cpp


Index: clang-tools-extra/test/clang-tidy/checkers/bugprone-stringview-nullptr.cpp
===================================================================
--- clang-tools-extra/test/clang-tidy/checkers/bugprone-stringview-nullptr.cpp
+++ clang-tools-extra/test/clang-tidy/checkers/bugprone-stringview-nullptr.cpp
@@ -215,6 +215,37 @@
     // CHECK-MESSAGES: :[[@LINE-1]]:48: warning: constructing{{.*}}default
     // CHECK-FIXES: {{^}}    (void)(static_cast<const std::string_view>("")) /* a28 */;
   }
+
+  // Return Value
+  {
+    (void)([] -> std::string_view { return nullptr; }) /* a29 */;
+    // CHECK-MESSAGES: :[[@LINE-1]]:44: warning: constructing{{.*}}default
+    // CHECK-FIXES: {{^}}    (void)([] -> std::string_view { return {}; }) /* a29 */;
+
+    (void)([] -> std::string_view { return (nullptr); }) /* a30 */;
+    // CHECK-MESSAGES: :[[@LINE-1]]:44: warning: constructing{{.*}}default
+    // CHECK-FIXES: {{^}}    (void)([] -> std::string_view { return {}; }) /* a30 */;
+
+    (void)([] -> std::string_view { return {nullptr}; }) /* a31 */;
+    // CHECK-MESSAGES: :[[@LINE-1]]:44: warning: constructing{{.*}}default
+    // CHECK-FIXES: {{^}}    (void)([] -> std::string_view { return {}; }) /* a31 */;
+
+    (void)([] -> std::string_view { return {(nullptr)}; }) /* a32 */;
+    // CHECK-MESSAGES: :[[@LINE-1]]:44: warning: constructing{{.*}}default
+    // CHECK-FIXES: {{^}}    (void)([] -> std::string_view { return {}; }) /* a32 */;
+
+    (void)([] -> std::string_view { return {{nullptr}}; }) /* a33 */;
+    // CHECK-MESSAGES: :[[@LINE-1]]:44: warning: constructing{{.*}}default
+    // CHECK-FIXES: {{^}}    (void)([] -> std::string_view { return {}; }) /* a33 */;
+
+    (void)([] -> std::string_view { return {{(nullptr)}}; }) /* a34 */;
+    // CHECK-MESSAGES: :[[@LINE-1]]:44: warning: constructing{{.*}}default
+    // CHECK-FIXES: {{^}}    (void)([] -> std::string_view { return {}; }) /* a34 */;
+
+    (void)([] -> std::string_view { return {{}}; }) /* a35 */;
+    // CHECK-MESSAGES: :[[@LINE-1]]:44: warning: constructing{{.*}}default
+    // CHECK-FIXES: {{^}}    (void)([] -> std::string_view { return {}; }) /* a35 */;
+  }
 }
 
 void stack_construction() /* b */ {
Index: clang-tools-extra/clang-tidy/bugprone/StringviewNullptrCheck.cpp
===================================================================
--- clang-tools-extra/clang-tidy/bugprone/StringviewNullptrCheck.cpp
+++ clang-tools-extra/clang-tidy/bugprone/StringviewNullptrCheck.cpp
@@ -74,6 +74,11 @@
           hasSourceExpression(StringViewConstructingFromNullExpr)),
       changeTo(node("null_argument_expr"), cat("\"\"")), construction_warning);
 
+  auto HandleTemporaryReturnValue = makeRule(
+      returnStmt(
+          hasReturnValue(ignoringImpCasts(StringViewConstructingFromNullExpr))),
+      changeTo(node("construct_expr"), cat("{}")), construction_warning);
+
   auto HandleStackCopyInitialization = makeRule(
       varDecl(hasInitializer(implicitCastExpr(
           ignoringImpCasts(StringViewConstructingFromNullExpr)))),
@@ -169,15 +174,23 @@
   return applyFirst(
       {HandleTemporaryCXXFunctionalCastExpr,
        HandleTemporaryCXXTemporaryObjectExprAndCompoundLiteralExpr,
-       HandleTemporaryCStyleCastExpr, HandleTemporaryCXXStaticCastExpr,
-       HandleStackCopyInitialization, HandleStackDirectInitialization,
+       HandleTemporaryCStyleCastExpr,
+       HandleTemporaryCXXStaticCastExpr,
+       HandleTemporaryReturnValue,
+       HandleStackCopyInitialization,
+       HandleStackDirectInitialization,
        HandleStackDirectListAndCopyListInitialization,
-       HandleFieldCopyInitialization, HandleFieldOtherInitialization,
-       HandleConstructorInitialization, HandleDefaultArgumentInitialization,
-       HandleDefaultArgumentListInitialization, HandleHeapInitialization,
+       HandleFieldCopyInitialization,
+       HandleFieldOtherInitialization,
+       HandleConstructorInitialization,
+       HandleDefaultArgumentInitialization,
+       HandleDefaultArgumentListInitialization,
+       HandleHeapInitialization,
        HandleFunctionArgumentInitialization,
-       HandleFunctionArgumentListInitialization, HandleAssignment,
-       HandleRelativeComparison, HandleEmptyEqualityComparison,
+       HandleFunctionArgumentListInitialization,
+       HandleAssignment,
+       HandleRelativeComparison,
+       HandleEmptyEqualityComparison,
        HandleNonEmptyEqualityComparison});
 }
 


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