[clang-tools-extra] [clang-tidy] modernize-use-std-print, format: Fix checks with Abseil functions (PR #142312)
Mike Crowe via cfe-commits
cfe-commits at lists.llvm.org
Sun Jun 1 07:53:26 PDT 2025
https://github.com/mikecrowe created https://github.com/llvm/llvm-project/pull/142312
These checks previously failed with absl::StrFormat and absl::PrintF etc. with:
Unable to use 'std::format' instead of 'StrFormat' because first
argument is not a narrow string literal [modernize-use-std-format]
because FormatStringConverter was rejecting the format string if it had already converted into a different type. Fix the tests so that they check this case properly by accepting string_view rather than const char
* and fix the check so that these tests pass. Update the existing tests that checked for the error message that can no longer happen.
Fixes: https://github.com/llvm/llvm-project/issues/129484
>From 929c892a18e57d0371adab5c8ab9aa55dce3f192 Mon Sep 17 00:00:00 2001
From: Mike Crowe <mac at mcrowe.com>
Date: Thu, 29 May 2025 21:19:11 +0100
Subject: [PATCH] [clang-tidy] modernize-use-std-print,format: Fix checks with
Abseil functions
These checks previously failed with absl::StrFormat and absl::PrintF
etc. with:
Unable to use 'std::format' instead of 'StrFormat' because first
argument is not a narrow string literal [modernize-use-std-format]
because FormatStringConverter was rejecting the format string if it had
already converted into a different type. Fix the tests so that they
check this case properly by accepting string_view rather than const char
* and fix the check so that these tests pass. Update the existing tests
that checked for the error message that can no longer happen.
Fixes: https://github.com/llvm/llvm-project/issues/129484
---
.../utils/FormatStringConverter.cpp | 8 ++----
clang-tools-extra/docs/ReleaseNotes.rst | 10 ++++++++
.../modernize/use-std-format-custom.cpp | 17 ++++++++-----
.../checkers/modernize/use-std-format.cpp | 4 +--
.../checkers/modernize/use-std-print-absl.cpp | 5 ++--
.../modernize/use-std-print-custom.cpp | 25 ++++++++++++-------
6 files changed, 44 insertions(+), 25 deletions(-)
diff --git a/clang-tools-extra/clang-tidy/utils/FormatStringConverter.cpp b/clang-tools-extra/clang-tidy/utils/FormatStringConverter.cpp
index 7f4ccca84faa5..e1c1bee97f6d4 100644
--- a/clang-tools-extra/clang-tidy/utils/FormatStringConverter.cpp
+++ b/clang-tools-extra/clang-tidy/utils/FormatStringConverter.cpp
@@ -207,13 +207,9 @@ FormatStringConverter::FormatStringConverter(
ArgsOffset(FormatArgOffset + 1), LangOpts(LO) {
assert(ArgsOffset <= NumArgs);
FormatExpr = llvm::dyn_cast<StringLiteral>(
- Args[FormatArgOffset]->IgnoreImplicitAsWritten());
+ Args[FormatArgOffset]->IgnoreUnlessSpelledInSource());
- if (!FormatExpr || !FormatExpr->isOrdinary()) {
- // Function must have a narrow string literal as its first argument.
- conversionNotPossible("first argument is not a narrow string literal");
- return;
- }
+ assert(FormatExpr && FormatExpr->isOrdinary());
if (const std::optional<StringRef> MaybeMacroName =
formatStringContainsUnreplaceableMacro(Call, FormatExpr, SM, PP);
diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
index e0f81a032c38d..3bd601ebdb580 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -232,10 +232,20 @@ Changes in existing checks
matched scenarios of ``find`` and ``rfind`` methods and fixing false
positives when those methods were called with 3 arguments.
+- Improved :doc:`modernize-use-std-print
+ <clang-tidy/checks/modernize/use-std-print>` check to correctly match
+ when the format string is converted to a different type by an implicit
+ constructor call.
+
- Improved :doc:`modernize-use-std-numbers
<clang-tidy/checks/modernize/use-std-numbers>` check to support math
functions of different precisions.
+- Improved :doc:`modernize-use-std-format
+ <clang-tidy/checks/modernize/use-std-format>` check to correctly match
+ when the format string is converted to a different type by an implicit
+ constructor call.
+
- Improved :doc:`performance-move-const-arg
<clang-tidy/checks/performance/move-const-arg>` check by fixing false
negatives on ternary operators calling ``std::move``.
diff --git a/clang-tools-extra/test/clang-tidy/checkers/modernize/use-std-format-custom.cpp b/clang-tools-extra/test/clang-tidy/checkers/modernize/use-std-format-custom.cpp
index 7da0bb02ad766..0f3458e61856a 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/modernize/use-std-format-custom.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/modernize/use-std-format-custom.cpp
@@ -2,7 +2,7 @@
// RUN: -std=c++20 %s modernize-use-std-format %t -- \
// RUN: -config="{CheckOptions: { \
// RUN: modernize-use-std-format.StrictMode: true, \
-// RUN: modernize-use-std-format.StrFormatLikeFunctions: '::strprintf; mynamespace::strprintf2; bad_format_type_strprintf', \
+// RUN: modernize-use-std-format.StrFormatLikeFunctions: '::strprintf; mynamespace::strprintf2; any_format_type_strprintf', \
// RUN: modernize-use-std-format.ReplacementFormatFunction: 'fmt::format', \
// RUN: modernize-use-std-format.FormatHeader: '<fmt/core.h>' \
// RUN: }}" \
@@ -10,7 +10,7 @@
// RUN: %check_clang_tidy -check-suffixes=,NOTSTRICT \
// RUN: -std=c++20 %s modernize-use-std-format %t -- \
// RUN: -config="{CheckOptions: { \
-// RUN: modernize-use-std-format.StrFormatLikeFunctions: '::strprintf; mynamespace::strprintf2; bad_format_type_strprintf', \
+// RUN: modernize-use-std-format.StrFormatLikeFunctions: '::strprintf; mynamespace::strprintf2; any_format_type_strprintf', \
// RUN: modernize-use-std-format.ReplacementFormatFunction: 'fmt::format', \
// RUN: modernize-use-std-format.FormatHeader: '<fmt/core.h>' \
// RUN: }}" \
@@ -56,12 +56,17 @@ std::string A(const std::string &in)
struct S {
S(...);
};
-std::string bad_format_type_strprintf(const S &, ...);
+std::string any_format_type_strprintf(const S &, ...);
-std::string unsupported_format_parameter_type()
+void unsupported_format_parameter_types()
{
// No fixes here because the format parameter of the function called is not a
// string.
- return bad_format_type_strprintf("");
-// CHECK-MESSAGES: [[@LINE-1]]:10: warning: unable to use 'fmt::format' instead of 'bad_format_type_strprintf' because first argument is not a narrow string literal [modernize-use-std-format]
+ auto s1 = any_format_type_strprintf(L"");
+ auto s2 = any_format_type_strprintf(42);
+
+ // But if we do pass a character string then that ought to be acceptable.
+ auto s3 = any_format_type_strprintf("Hello %s", "world");
+ // CHECK-MESSAGES: [[@LINE-1]]:13: warning: use 'fmt::format' instead of 'any_format_type_strprintf' [modernize-use-std-format]
+ // CHECK-FIXES: auto s3 = fmt::format("Hello {}", "world");
}
diff --git a/clang-tools-extra/test/clang-tidy/checkers/modernize/use-std-format.cpp b/clang-tools-extra/test/clang-tidy/checkers/modernize/use-std-format.cpp
index 1a241e3712210..bf56f15c4d632 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/modernize/use-std-format.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/modernize/use-std-format.cpp
@@ -16,8 +16,8 @@
namespace absl
{
-template <typename S, typename... Args>
-std::string StrFormat(const S &format, const Args&... args);
+template <typename... Args>
+std::string StrFormat(const std::string &format, const Args&... args);
} // namespace absl
template <typename T>
diff --git a/clang-tools-extra/test/clang-tidy/checkers/modernize/use-std-print-absl.cpp b/clang-tools-extra/test/clang-tidy/checkers/modernize/use-std-print-absl.cpp
index 83fbd2e7500c5..ce274ddfe95c4 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/modernize/use-std-print-absl.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/modernize/use-std-print-absl.cpp
@@ -9,15 +9,16 @@
#include <cstdio>
#include <string.h>
+#include <string>
namespace absl
{
// Use const char * for the format since the real type is hard to mock up.
template <typename... Args>
-int PrintF(const char *format, const Args&... args);
+int PrintF(const std::string_view &format, const Args&... args);
template <typename... Args>
-int FPrintF(FILE* output, const char *format, const Args&... args);
+int FPrintF(FILE* output, const std::string_view &format, const Args&... args);
}
void printf_simple() {
diff --git a/clang-tools-extra/test/clang-tidy/checkers/modernize/use-std-print-custom.cpp b/clang-tools-extra/test/clang-tidy/checkers/modernize/use-std-print-custom.cpp
index 687b8c0780b01..2c6a651b679d6 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/modernize/use-std-print-custom.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/modernize/use-std-print-custom.cpp
@@ -1,8 +1,8 @@
// RUN: %check_clang_tidy -std=c++23 %s modernize-use-std-print %t -- \
// RUN: -config="{CheckOptions: \
// RUN: { \
-// RUN: modernize-use-std-print.PrintfLikeFunctions: 'unqualified_printf;::myprintf; mynamespace::myprintf2; bad_format_type_printf; fmt::printf', \
-// RUN: modernize-use-std-print.FprintfLikeFunctions: '::myfprintf; mynamespace::myfprintf2; bad_format_type_fprintf; fmt::fprintf' \
+// RUN: modernize-use-std-print.PrintfLikeFunctions: 'unqualified_printf;::myprintf; mynamespace::myprintf2; any_format_type_printf; fmt::printf', \
+// RUN: modernize-use-std-print.FprintfLikeFunctions: '::myfprintf; mynamespace::myfprintf2; any_format_type_fprintf; fmt::fprintf' \
// RUN: } \
// RUN: }" \
// RUN: -- -isystem %clang_tidy_headers
@@ -98,18 +98,25 @@ void wide_string_not_supported() {
struct S {
S(...) {}
};
-int bad_format_type_printf(const S &, ...);
-int bad_format_type_fprintf(FILE *, const S &, ...);
+int any_format_type_printf(const S &, ...);
+int any_format_type_fprintf(FILE *, const S &, ...);
void unsupported_format_parameter_type()
{
// No fixes here because the format parameter of the function called is not a
// string.
- bad_format_type_printf("Hello %s", "world");
-// CHECK-MESSAGES: [[@LINE-1]]:3: warning: unable to use 'std::print' instead of 'bad_format_type_printf' because first argument is not a narrow string literal [modernize-use-std-print]
-
- bad_format_type_fprintf(stderr, "Hello %s", "world");
-// CHECK-MESSAGES: [[@LINE-1]]:3: warning: unable to use 'std::print' instead of 'bad_format_type_fprintf' because first argument is not a narrow string literal [modernize-use-std-print]
+ any_format_type_printf(L"Hello %s", "world");
+ any_format_type_fprintf(stderr, L"Hello %s", "world");
+ any_format_type_printf(42);
+ any_format_type_fprintf(stderr, 42L);
+
+ // But if we do pass a character string then that ought to be acceptable.
+ any_format_type_printf("Hello %s\n", "world");
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: use 'std::println' instead of 'any_format_type_printf' [modernize-use-std-print]
+ // CHECK-FIXES: std::println("Hello {}", "world");
+ any_format_type_fprintf(stderr, "Hello %s\n", "world");
+ // CHECK-MESSAGES: [[@LINE-1]]:3: warning: use 'std::println' instead of 'any_format_type_fprintf' [modernize-use-std-print]
+ // CHECK-FIXES: std::println(stderr, "Hello {}", "world");
}
namespace fmt {
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