[clang-tidy] rewrite matchers in modernize-use-starts-ends-with (#112101)

Rewrite the AST matchers for slightly more composability. 
Furthermore, check that the `starts_with` and `ends_with`
functions return a `bool`.
There is one behavioral change, in that the methods of a class (and
transitive classes) are searched once for a matching
`starts_with`/`ends_with` function, picking the first it can find.
Previously, the matchers would try to find `starts_with`, then
`startsWith`, and finally, `startswith`. Now, the first of the three
that
is encountered will be the matched method.

---------

Co-authored-by: Nicolas van Kempen <nvankemp@gmail.com>
This commit is contained in:
Julian Schmidt 2024-10-18 09:07:21 +02:00 committed by GitHub
parent e8509a43ac
commit 18b50189a7
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2 changed files with 39 additions and 56 deletions

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@ -9,7 +9,8 @@
#include "UseStartsEndsWithCheck.h"
#include "../utils/ASTUtils.h"
#include "../utils/OptionsUtils.h"
#include "../utils/Matchers.h"
#include "clang/ASTMatchers/ASTMatchers.h"
#include "clang/Lex/Lexer.h"
#include <string>
@ -82,60 +83,53 @@ UseStartsEndsWithCheck::UseStartsEndsWithCheck(StringRef Name,
void UseStartsEndsWithCheck::registerMatchers(MatchFinder *Finder) {
const auto ZeroLiteral = integerLiteral(equals(0));
const auto HasStartsWithMethodWithName = [](const std::string &Name) {
return hasMethod(
cxxMethodDecl(hasName(Name), isConst(), parameterCountIs(1))
.bind("starts_with_fun"));
const auto ClassTypeWithMethod = [](const StringRef MethodBoundName,
const auto... Methods) {
return cxxRecordDecl(anyOf(
hasMethod(cxxMethodDecl(isConst(), parameterCountIs(1),
returns(booleanType()), hasAnyName(Methods))
.bind(MethodBoundName))...));
};
const auto HasStartsWithMethod =
anyOf(HasStartsWithMethodWithName("starts_with"),
HasStartsWithMethodWithName("startsWith"),
HasStartsWithMethodWithName("startswith"));
const auto OnClassWithStartsWithFunction =
on(hasType(hasCanonicalType(hasDeclaration(cxxRecordDecl(
anyOf(HasStartsWithMethod,
hasAnyBase(hasType(hasCanonicalType(
hasDeclaration(cxxRecordDecl(HasStartsWithMethod)))))))))));
const auto HasEndsWithMethodWithName = [](const std::string &Name) {
return hasMethod(
cxxMethodDecl(hasName(Name), isConst(), parameterCountIs(1))
.bind("ends_with_fun"));
};
const auto HasEndsWithMethod = anyOf(HasEndsWithMethodWithName("ends_with"),
HasEndsWithMethodWithName("endsWith"),
HasEndsWithMethodWithName("endswith"));
const auto OnClassWithEndsWithFunction =
on(expr(hasType(hasCanonicalType(hasDeclaration(cxxRecordDecl(
anyOf(HasEndsWithMethod,
hasAnyBase(hasType(hasCanonicalType(hasDeclaration(
cxxRecordDecl(HasEndsWithMethod)))))))))))
.bind("haystack"));
const auto OnClassWithStartsWithFunction =
ClassTypeWithMethod("starts_with_fun", "starts_with", "startsWith",
"startswith", "StartsWith");
const auto OnClassWithEndsWithFunction = ClassTypeWithMethod(
"ends_with_fun", "ends_with", "endsWith", "endswith", "EndsWith");
// Case 1: X.find(Y) [!=]= 0 -> starts_with.
const auto FindExpr = cxxMemberCallExpr(
anyOf(argumentCountIs(1), hasArgument(1, ZeroLiteral)),
callee(cxxMethodDecl(hasName("find")).bind("find_fun")),
OnClassWithStartsWithFunction, hasArgument(0, expr().bind("needle")));
callee(
cxxMethodDecl(hasName("find"), ofClass(OnClassWithStartsWithFunction))
.bind("find_fun")),
hasArgument(0, expr().bind("needle")));
// Case 2: X.rfind(Y, 0) [!=]= 0 -> starts_with.
const auto RFindExpr = cxxMemberCallExpr(
hasArgument(1, ZeroLiteral),
callee(cxxMethodDecl(hasName("rfind")).bind("find_fun")),
OnClassWithStartsWithFunction, hasArgument(0, expr().bind("needle")));
callee(cxxMethodDecl(hasName("rfind"),
ofClass(OnClassWithStartsWithFunction))
.bind("find_fun")),
hasArgument(0, expr().bind("needle")));
// Case 3: X.compare(0, LEN(Y), Y) [!=]= 0 -> starts_with.
const auto CompareExpr = cxxMemberCallExpr(
argumentCountIs(3), hasArgument(0, ZeroLiteral),
callee(cxxMethodDecl(hasName("compare")).bind("find_fun")),
OnClassWithStartsWithFunction, hasArgument(2, expr().bind("needle")),
callee(cxxMethodDecl(hasName("compare"),
ofClass(OnClassWithStartsWithFunction))
.bind("find_fun")),
hasArgument(2, expr().bind("needle")),
hasArgument(1, lengthExprForStringNode("needle")));
// Case 4: X.compare(LEN(X) - LEN(Y), LEN(Y), Y) [!=]= 0 -> ends_with.
const auto CompareEndsWithExpr = cxxMemberCallExpr(
argumentCountIs(3),
callee(cxxMethodDecl(hasName("compare")).bind("find_fun")),
OnClassWithEndsWithFunction, hasArgument(2, expr().bind("needle")),
callee(cxxMethodDecl(hasName("compare"),
ofClass(OnClassWithEndsWithFunction))
.bind("find_fun")),
on(expr().bind("haystack")), hasArgument(2, expr().bind("needle")),
hasArgument(1, lengthExprForStringNode("needle")),
hasArgument(0,
binaryOperator(hasOperatorName("-"),
@ -145,7 +139,7 @@ void UseStartsEndsWithCheck::registerMatchers(MatchFinder *Finder) {
// All cases comparing to 0.
Finder->addMatcher(
binaryOperator(
hasAnyOperatorName("==", "!="),
matchers::isEqualityOperator(),
hasOperands(cxxMemberCallExpr(anyOf(FindExpr, RFindExpr, CompareExpr,
CompareEndsWithExpr))
.bind("find_expr"),
@ -156,7 +150,7 @@ void UseStartsEndsWithCheck::registerMatchers(MatchFinder *Finder) {
// Case 5: X.rfind(Y) [!=]= LEN(X) - LEN(Y) -> ends_with.
Finder->addMatcher(
binaryOperator(
hasAnyOperatorName("==", "!="),
matchers::isEqualityOperator(),
hasOperands(
cxxMemberCallExpr(
anyOf(
@ -166,8 +160,10 @@ void UseStartsEndsWithCheck::registerMatchers(MatchFinder *Finder) {
1,
anyOf(declRefExpr(to(varDecl(hasName("npos")))),
memberExpr(member(hasName("npos"))))))),
callee(cxxMethodDecl(hasName("rfind")).bind("find_fun")),
OnClassWithEndsWithFunction,
callee(cxxMethodDecl(hasName("rfind"),
ofClass(OnClassWithEndsWithFunction))
.bind("find_fun")),
on(expr().bind("haystack")),
hasArgument(0, expr().bind("needle")))
.bind("find_expr"),
binaryOperator(hasOperatorName("-"),
@ -190,9 +186,8 @@ void UseStartsEndsWithCheck::check(const MatchFinder::MatchResult &Result) {
const CXXMethodDecl *ReplacementFunction =
StartsWithFunction ? StartsWithFunction : EndsWithFunction;
if (ComparisonExpr->getBeginLoc().isMacroID()) {
if (ComparisonExpr->getBeginLoc().isMacroID())
return;
}
const bool Neg = ComparisonExpr->getOpcode() == BO_NE;
@ -220,9 +215,8 @@ void UseStartsEndsWithCheck::check(const MatchFinder::MatchResult &Result) {
(ReplacementFunction->getName() + "(").str());
// Add possible negation '!'.
if (Neg) {
if (Neg)
Diagnostic << FixItHint::CreateInsertion(FindExpr->getBeginLoc(), "!");
}
}
} // namespace clang::tidy::modernize

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@ -32,14 +32,9 @@ struct prefer_underscore_version_flip {
size_t find(const char *s, size_t pos = 0) const;
};
struct prefer_underscore_version_inherit : public string_like {
bool startsWith(const char *s) const;
};
void test(std::string s, std::string_view sv, sub_string ss, sub_sub_string sss,
string_like sl, string_like_camel slc, prefer_underscore_version puv,
prefer_underscore_version_flip puvf,
prefer_underscore_version_inherit puvi) {
prefer_underscore_version_flip puvf) {
s.find("a") == 0;
// CHECK-MESSAGES: :[[@LINE-1]]:{{[0-9]+}}: warning: use starts_with instead of find() == 0
// CHECK-FIXES: s.starts_with("a");
@ -153,12 +148,6 @@ void test(std::string s, std::string_view sv, sub_string ss, sub_sub_string sss,
// CHECK-MESSAGES: :[[@LINE-1]]:{{[0-9]+}}: warning: use starts_with
// CHECK-FIXES: puvf.starts_with("a");
// Here, the subclass has startsWith, the superclass has starts_with.
// We prefer the version from the subclass.
puvi.find("a") == 0;
// CHECK-MESSAGES: :[[@LINE-1]]:{{[0-9]+}}: warning: use startsWith
// CHECK-FIXES: puvi.startsWith("a");
s.compare(0, 1, "a") == 0;
// CHECK-MESSAGES: :[[@LINE-1]]:{{[0-9]+}}: warning: use starts_with instead of compare() == 0
// CHECK-FIXES: s.starts_with("a");