[clang-tools-extra] [clang-tidy]Add new check readability-avoid-nested-conditional-operator (PR #78022)
Congcong Cai via cfe-commits
cfe-commits at lists.llvm.org
Sat Jan 13 00:02:21 PST 2024
https://github.com/HerrCai0907 created https://github.com/llvm/llvm-project/pull/78022
Finds nested conditional operator.
Nested conditional operators lead code hard to understand, so they should be splited as several statement and stored in temporary varibale.
>From 0988bb25a35e5d50b44bf53d459098777280c3e5 Mon Sep 17 00:00:00 2001
From: Congcong Cai <congcongcai0907 at 163.com>
Date: Sat, 13 Jan 2024 16:00:16 +0800
Subject: [PATCH] [clang-tidy]Add new check
readability-avoid-nested-conditional-operator Finds nested conditional
operator. Nested conditional operators lead code hard to understand, so they
should be splited as several statement and stored in temporary varibale.
---
.../AvoidNestedConditionalOperatorCheck.cpp | 56 +++++++++++++++++++
.../AvoidNestedConditionalOperatorCheck.h | 33 +++++++++++
.../clang-tidy/readability/CMakeLists.txt | 1 +
.../readability/ReadabilityTidyModule.cpp | 3 +
clang-tools-extra/docs/ReleaseNotes.rst | 5 ++
.../docs/clang-tidy/checks/list.rst | 1 +
.../avoid-nested-conditional-operator.rst | 20 +++++++
.../avoid-nested-conditional-operator.cpp | 23 ++++++++
8 files changed, 142 insertions(+)
create mode 100644 clang-tools-extra/clang-tidy/readability/AvoidNestedConditionalOperatorCheck.cpp
create mode 100644 clang-tools-extra/clang-tidy/readability/AvoidNestedConditionalOperatorCheck.h
create mode 100644 clang-tools-extra/docs/clang-tidy/checks/readability/avoid-nested-conditional-operator.rst
create mode 100644 clang-tools-extra/test/clang-tidy/checkers/readability/avoid-nested-conditional-operator.cpp
diff --git a/clang-tools-extra/clang-tidy/readability/AvoidNestedConditionalOperatorCheck.cpp b/clang-tools-extra/clang-tidy/readability/AvoidNestedConditionalOperatorCheck.cpp
new file mode 100644
index 00000000000000..a0278c3ae32fa7
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/readability/AvoidNestedConditionalOperatorCheck.cpp
@@ -0,0 +1,56 @@
+//===--- AvoidNestedConditionalOperatorCheck.cpp - clang-tidy ----------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "AvoidNestedConditionalOperatorCheck.h"
+#include "clang/AST/Expr.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/ASTMatchers/ASTMatchers.h"
+#include "clang/Basic/DiagnosticIDs.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang::tidy::readability {
+
+namespace {
+constexpr const char *Description = "don't use nested conditional operator";
+constexpr const char *OutSideConditionalOperatorNote =
+ "outside conditional operator here";
+} // namespace
+
+void AvoidNestedConditionalOperatorCheck::registerMatchers(
+ MatchFinder *Finder) {
+ Finder->addMatcher(
+ conditionalOperator(
+ anyOf(
+ hasCondition(ignoringParenCasts(
+ conditionalOperator().bind("nested-conditional-operator"))),
+ hasTrueExpression(ignoringParenCasts(
+ conditionalOperator().bind("nested-conditional-operator"))),
+ hasFalseExpression(ignoringParenCasts(
+ conditionalOperator().bind("nested-conditional-operator")))))
+ .bind("conditional-operator"),
+ this);
+}
+
+void AvoidNestedConditionalOperatorCheck::check(
+ const MatchFinder::MatchResult &Result) {
+ const auto *CO =
+ Result.Nodes.getNodeAs<ConditionalOperator>("conditional-operator");
+ const auto *NCO = Result.Nodes.getNodeAs<ConditionalOperator>(
+ "nested-conditional-operator");
+ assert(CO);
+ assert(NCO);
+
+ if (CO->getBeginLoc().isMacroID() || NCO->getBeginLoc().isMacroID())
+ return;
+
+ diag(NCO->getBeginLoc(), Description);
+ diag(CO->getBeginLoc(), OutSideConditionalOperatorNote, DiagnosticIDs::Note);
+}
+
+} // namespace clang::tidy::readability
diff --git a/clang-tools-extra/clang-tidy/readability/AvoidNestedConditionalOperatorCheck.h b/clang-tools-extra/clang-tidy/readability/AvoidNestedConditionalOperatorCheck.h
new file mode 100644
index 00000000000000..2f82ea86cd849d
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/readability/AvoidNestedConditionalOperatorCheck.h
@@ -0,0 +1,33 @@
+//===--- AvoidNestedConditionalOperatorCheck.h - clang-tidy --*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_READABILITY_AVOIDNestedConditionalOperatorCHECK_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_READABILITY_AVOIDNestedConditionalOperatorCHECK_H
+
+#include "../ClangTidyCheck.h"
+
+namespace clang::tidy::readability {
+
+/// Finds nested conditional operator.
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/readability/avoid-nested-conditional-operator.html
+class AvoidNestedConditionalOperatorCheck : public ClangTidyCheck {
+public:
+ AvoidNestedConditionalOperatorCheck(StringRef Name, ClangTidyContext *Context)
+ : ClangTidyCheck(Name, Context) {}
+ void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+ void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+ std::optional<TraversalKind> getCheckTraversalKind() const override {
+ return TK_IgnoreUnlessSpelledInSource;
+ }
+};
+
+} // namespace clang::tidy::readability
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_READABILITY_AVOIDNestedConditionalOperatorCHECK_H
diff --git a/clang-tools-extra/clang-tidy/readability/CMakeLists.txt b/clang-tools-extra/clang-tidy/readability/CMakeLists.txt
index 408c822b861c5f..fa571d5dd7650d 100644
--- a/clang-tools-extra/clang-tidy/readability/CMakeLists.txt
+++ b/clang-tools-extra/clang-tidy/readability/CMakeLists.txt
@@ -5,6 +5,7 @@ set(LLVM_LINK_COMPONENTS
add_clang_library(clangTidyReadabilityModule
AvoidConstParamsInDecls.cpp
+ AvoidNestedConditionalOperatorCheck.cpp
AvoidReturnWithVoidValueCheck.cpp
AvoidUnconditionalPreprocessorIfCheck.cpp
BracesAroundStatementsCheck.cpp
diff --git a/clang-tools-extra/clang-tidy/readability/ReadabilityTidyModule.cpp b/clang-tools-extra/clang-tidy/readability/ReadabilityTidyModule.cpp
index 0b0aad7c0dcb36..f769752c5de5fa 100644
--- a/clang-tools-extra/clang-tidy/readability/ReadabilityTidyModule.cpp
+++ b/clang-tools-extra/clang-tidy/readability/ReadabilityTidyModule.cpp
@@ -10,6 +10,7 @@
#include "../ClangTidyModule.h"
#include "../ClangTidyModuleRegistry.h"
#include "AvoidConstParamsInDecls.h"
+#include "AvoidNestedConditionalOperatorCheck.h"
#include "AvoidReturnWithVoidValueCheck.h"
#include "AvoidUnconditionalPreprocessorIfCheck.h"
#include "BracesAroundStatementsCheck.h"
@@ -64,6 +65,8 @@ class ReadabilityModule : public ClangTidyModule {
void addCheckFactories(ClangTidyCheckFactories &CheckFactories) override {
CheckFactories.registerCheck<AvoidConstParamsInDecls>(
"readability-avoid-const-params-in-decls");
+ CheckFactories.registerCheck<AvoidNestedConditionalOperatorCheck>(
+ "readability-avoid-nested-conditional-operator");
CheckFactories.registerCheck<AvoidReturnWithVoidValueCheck>(
"readability-avoid-return-with-void-value");
CheckFactories.registerCheck<AvoidUnconditionalPreprocessorIfCheck>(
diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
index 3437b6cf9b59e9..7ed4bcf1ff92ac 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -224,6 +224,11 @@ New checks
Recommends the smallest possible underlying type for an ``enum`` or ``enum``
class based on the range of its enumerators.
+- New :doc:`readability-avoid-nested-conditional-operator
+ <clang-tidy/checks/readability/avoid-nested-conditional-operator>` check.
+
+ Finds nested conditional operator.
+
- New :doc:`readability-reference-to-constructed-temporary
<clang-tidy/checks/readability/reference-to-constructed-temporary>` check.
diff --git a/clang-tools-extra/docs/clang-tidy/checks/list.rst b/clang-tools-extra/docs/clang-tidy/checks/list.rst
index 2f86121ad87299..fd65bdc1e43f8d 100644
--- a/clang-tools-extra/docs/clang-tidy/checks/list.rst
+++ b/clang-tools-extra/docs/clang-tidy/checks/list.rst
@@ -337,6 +337,7 @@ Clang-Tidy Checks
:doc:`portability-simd-intrinsics <portability/simd-intrinsics>`,
:doc:`portability-std-allocator-const <portability/std-allocator-const>`,
:doc:`readability-avoid-const-params-in-decls <readability/avoid-const-params-in-decls>`, "Yes"
+ :doc:`readability-avoid-nested-conditional-operator <readability/avoid-nested-conditional-operator>`, "Yes"
:doc:`readability-avoid-return-with-void-value <readability/avoid-return-with-void-value>`,
:doc:`readability-avoid-unconditional-preprocessor-if <readability/avoid-unconditional-preprocessor-if>`,
:doc:`readability-braces-around-statements <readability/braces-around-statements>`, "Yes"
diff --git a/clang-tools-extra/docs/clang-tidy/checks/readability/avoid-nested-conditional-operator.rst b/clang-tools-extra/docs/clang-tidy/checks/readability/avoid-nested-conditional-operator.rst
new file mode 100644
index 00000000000000..db4ce7de87a9e7
--- /dev/null
+++ b/clang-tools-extra/docs/clang-tidy/checks/readability/avoid-nested-conditional-operator.rst
@@ -0,0 +1,20 @@
+.. title:: clang-tidy - readability-avoid-nested-conditional-operator
+
+readability-avoid-nested-conditional-operator
+=================================================
+
+Finds nested conditional operator.
+
+Nested conditional operators lead code hard to understand, so they should be
+splited as several statement and stored in temporary varibale.
+
+Examples:
+
+.. code-block:: c++
+
+ int NestInConditional = (condition1 ? true1 : false1) ? true2 : false2;
+ int NestInTrue = condition1 ? (condition2 ? true1 : false1) : false2;
+ int NestInFalse = condition1 ? true1 : condition2 ? true2 : false1;
+
+This check implements part of `AUTOSAR C++14 Rule A5-16-1
+<https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#Rc-constref>`_.
diff --git a/clang-tools-extra/test/clang-tidy/checkers/readability/avoid-nested-conditional-operator.cpp b/clang-tools-extra/test/clang-tidy/checkers/readability/avoid-nested-conditional-operator.cpp
new file mode 100644
index 00000000000000..fd2d592544ddd0
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/checkers/readability/avoid-nested-conditional-operator.cpp
@@ -0,0 +1,23 @@
+// RUN: %check_clang_tidy %s readability-avoid-nested-conditional-operator %t
+
+int NestInConditional = (true ? true : false) ? 1 : 2;
+// CHECK-MESSAGES: :[[@LINE-1]]:26: warning: don't use nested conditional operator
+// CHECK-MESSAGES: :[[@LINE-2]]:25: note: outside conditional operator here
+
+int NestInTrue = true ? (true ? 1 : 2) : 2;
+// CHECK-MESSAGES: :[[@LINE-1]]:26: warning: don't use nested conditional operator
+// CHECK-MESSAGES: :[[@LINE-2]]:18: note: outside conditional operator here
+
+int NestInFalse = true ? 1 : true ? 1 : 2;
+// CHECK-MESSAGES: :[[@LINE-1]]:30: warning: don't use nested conditional operator
+// CHECK-MESSAGES: :[[@LINE-2]]:19: note: outside conditional operator here
+int NestInFalse2 = true ? 1 : (true ? 1 : 2);
+// CHECK-MESSAGES: :[[@LINE-1]]:32: warning: don't use nested conditional operator
+// CHECK-MESSAGES: :[[@LINE-2]]:20: note: outside conditional operator here
+
+int NestWithParensis = true ? 1 : ((((true ? 1 : 2))));
+// CHECK-MESSAGES: :[[@LINE-1]]:39: warning: don't use nested conditional operator
+// CHECK-MESSAGES: :[[@LINE-2]]:24: note: outside conditional operator here
+
+#define CONDITIONAL_EXPR (true ? 1 : 2)
+int NestWithMacro = true ? CONDITIONAL_EXPR : 2;
More information about the cfe-commits
mailing list