[clang-tidy] modernize-use-std-print,format: Fix checks with Abseil functions #142312
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@llvm/pr-subscribers-clang-tools-extra @llvm/pr-subscribers-clang-tidy Author: Mike Crowe (mikecrowe) ChangesThese checks previously failed with absl::StrFormat and absl::PrintF etc. with: Unable to use 'std::format' instead of 'StrFormat' because first 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
Fixes: #129484 Full diff: https://github.com/llvm/llvm-project/pull/142312.diff 6 Files Affected:
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 {
|
Contributor
Author
|
Thanks to @gle8098 who suggested the fix for this. |
EugeneZelenko
requested review from
HerrCai0907,
PiotrZSL,
carlosgalvezp and
vbvictor
vbvictor
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Ping? |
vbvictor
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Jul 13, 2025
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LGTM
As I understand now, IgnoreImplicitAsWritten does not skip CXXConstructExpr and other similar nodes but IgnoreUnlessSpelledInSource does. To drill down to the StringLiteral we need to use IgnoreUnlessSpelledInSource.
https://godbolt.org/z/PxGGx9196
Contributor
Author
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@vbvictor Thanks for the review. I've rebased (fixing conflicts on the release notes) and squashed the changes. I don't have commit access. Please can you land the change for me if you're still happy with it? |
Contributor
Sure, I'll merge in a couple of days in case anyone will want to look at the patch. |
Contributor
|
Could you rebase from latest main? |
…unctions 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: llvm#129484
Contributor
Author
Done.
Yeah, I thought that I'd got lucky with my last rebase when the section was empty but your changes snuck in first. :-) Thanks for doing this. |
Contributor
Author
|
Thanks @vbvictor! |
mahesh-attarde
pushed a commit
to mahesh-attarde/llvm-project
that referenced
this pull request
Jul 28, 2025
…unctions (llvm#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: llvm#129484
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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
Fixes: #129484