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Report error on duplicate named arg names #4367

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Merged
merged 10 commits into from
Mar 2, 2025
Merged

Report error on duplicate named arg names #4367

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167ec54
Report error on duplicate named arg names
dinomight Feb 22, 2025
233d8d9
Fix unused return warning
dinomight Feb 26, 2025
3d9a3e6
Fix formatting
dinomight Feb 26, 2025
93b1425
Refactor check function, optimize check function, remove expensive test
dinomight Mar 1, 2025
36a6908
Fix missing CTAD in C++11
dinomight Mar 1, 2025
b6be6fe
Fix GCC13 build and enable GCC10 C++11 build
dinomight Mar 1, 2025
1c156a3
Fix formatting
dinomight Mar 1, 2025
9800147
Fix formatting, again
dinomight Mar 1, 2025
7cf7957
Remove init methods, simplify const usage, simplify check function, r…
dinomight Mar 2, 2025
e3bfecd
Run clang-format
dinomight Mar 2, 2025
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16 changes: 16 additions & 0 deletions include/fmt/base.h
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Original file line number Diff line number Diff line change
Expand Up @@ -1064,13 +1064,28 @@ template <typename Char> struct named_arg_info {
int id;
};

template <typename Char>
FMT_CONSTEXPR void check_for_duplicate(named_arg_info<Char>* named_args,
int named_arg_index,
basic_string_view<Char> arg_name) {
if (named_arg_index <= 0) return;
Comment on lines +1068 to +1071
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As it turned out the actual change that worked around the gcc bug was removing const in named_args, not adding the check =)

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OK, that's kind of funny. Which const was it, cause I had a lot 😄 Makes me curious why the const additions made it seem like it might not be initialized to GCC. Maybe it just generated some weird assumptions in the compiler checks as part of the inlining process?

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const named_arg_info<Char>*, looks like https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100417


for (auto i = 0; i < named_arg_index; ++i) {
if (basic_string_view<Char>(named_args[i].name) == arg_name) {
report_error("duplicate named args found");
}
}
}

template <typename Char, typename T, FMT_ENABLE_IF(!is_named_arg<T>::value)>
void init_named_arg(named_arg_info<Char>*, int& arg_index, int&, const T&) {
++arg_index;
}

template <typename Char, typename T, FMT_ENABLE_IF(is_named_arg<T>::value)>
void init_named_arg(named_arg_info<Char>* named_args, int& arg_index,
int& named_arg_index, const T& arg) {
check_for_duplicate<Char>(named_args, named_arg_index, arg.name);
named_args[named_arg_index++] = {arg.name, arg_index++};
}

Expand All @@ -1084,6 +1099,7 @@ template <typename T, typename Char,
FMT_ENABLE_IF(is_static_named_arg<T>::value)>
FMT_CONSTEXPR void init_static_named_arg(named_arg_info<Char>* named_args,
int& arg_index, int& named_arg_index) {
check_for_duplicate<Char>(named_args, named_arg_index, T::name);
named_args[named_arg_index++] = {T::name, arg_index++};
}

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2 changes: 2 additions & 0 deletions test/format-test.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -599,6 +599,8 @@ TEST(format_test, named_arg) {
EXPECT_THROW_MSG((void)fmt::format(runtime("{a} {}"), fmt::arg("a", 2), 42),
format_error,
"cannot switch from manual to automatic argument indexing");
EXPECT_THROW_MSG((void)fmt::format("{a}", fmt::arg("a", 1),
fmt::arg("a", 10)), format_error, "duplicate named args found");
}

TEST(format_test, auto_arg_index) {
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