Bump fmt from 12.1.0 to 12.2.0

[dependabot]

Bumps fmt from 12.1.0 to 12.2.0.

Release notes

Sourced from fmt's releases.

12.2.0

• Added a C11 API that brings fast, type-safe formatting to C. The new fmt-c library and fmt/fmt-c.h header use _Generic to dispatch on argument types and outperform printf/sprintf. For example:

  #include <fmt/fmt-c.h>
  fmt_print(stdout, "The answer is {}.\n", 42);

  (fmtlib/fmt#4663, fmtlib/fmt#4671, fmtlib/fmt#4696, fmtlib/fmt#4693, fmtlib/fmt#4694, fmtlib/fmt#4712, fmtlib/fmt#4789). Thanks @​Soumik15630m, @​Ferdi265 and @​localspook.

• Added a separate fmt::fmt-module CMake target for C++20 modules and a CI workflow that exercises module-based builds (fmtlib/fmt#4684, fmtlib/fmt#4685, fmtlib/fmt#4707, fmtlib/fmt#4708, fmtlib/fmt#4702, fmtlib/fmt#4709). Thanks @​MathewBensonCode.

• Enabled the full Dragonbox lookup cache by default for floating-point formatting unless optimizing for binary size (__OPTIMIZE_SIZE__), giving a ~10–25% speedup. Thanks Matthias Kretz for the suggestion. Average time per double on Apple M1 Pro (clang 17, random digits, smaller is better) measured with dtoa-benchmark:

  Method	Time (ns)
  fmt (full)	22.07
  fmt (compact)	29.55
  ryu	35.21
  double-conversion	81.81
  sprintf	726.27
  ostringstream	864.34

• Improved integer formatting performance by ~3% (fmtlib/fmt#4630). Thanks @​user202729.

• Optimized formatting into back-insert iterators by using bulk container append/insert methods (e.g. on std::vector<char> and custom string types) (fmtlib/fmt#4679). Thanks @​user202729.

• Reduced binary size of debug builds (~200k to ~85k in the bloat test) and improved compile speed when consteval is unavailable.

• Made path formatting lossless, preserving ill-formed UTF-16 sequences when converting std::filesystem::path to a narrow string.

• Added support for formatting std::unexpected (fmtlib/fmt#4675). Thanks @​17steen.

• Added overloads of fmt::println that take a fmt::text_style (fmtlib/fmt#4782). Thanks @​ahoarau.

• Added support for positional arguments as width and precision specifiers in fmt::printf (fmtlib/fmt#4643). Thanks @​KareemOtoum.

• Made FMT_STRING a no-op when FMT_USE_CONSTEVAL is enabled, since the consteval format-string constructor already provides compile-time validation (fmtlib/fmt#4611, fmtlib/fmt#4612). Thanks @​friedkeenan.

• Promoted fmt::detail::named_arg to the public API as fmt::named_arg and deprecated the detail alias (fmtlib/fmt#4683, fmtlib/fmt#4687). Thanks @​TPPPP72.

• Moved the std::byte formatter from fmt/format.h to fmt/std.h.

• Provided a default definition for fmt::is_contiguous (fmtlib/fmt#4731, fmtlib/fmt#4770). Thanks @​user202729 and @​phprus.

• Added the FMT_USE_FLOCKFILE macro to disable the use of flockfile (fmtlib/fmt#4646, fmtlib/fmt#4666). Thanks @​mvastola.

• Added include_guard(GLOBAL) so that {fmt} can be used in multiple submodules of the same project (fmtlib/fmt#4672). Thanks @​torsten48.

... (truncated)

Changelog

Sourced from fmt's changelog.

12.2.0 - 2026-06-16

• Added a C11 API that brings fast, type-safe formatting to C. The new fmt-c library and fmt/fmt-c.h header use _Generic to dispatch on argument types and outperform printf/sprintf. For example:

  #include <fmt/fmt-c.h>
  fmt_print(stdout, "The answer is {}.\n", 42);

  (fmtlib/fmt#4663, fmtlib/fmt#4671, fmtlib/fmt#4696, fmtlib/fmt#4693, fmtlib/fmt#4694, fmtlib/fmt#4712, fmtlib/fmt#4789). Thanks @​Soumik15630m, @​Ferdi265 and @​localspook.

• Added a separate fmt::fmt-module CMake target for C++20 modules and a CI workflow that exercises module-based builds (fmtlib/fmt#4684, fmtlib/fmt#4685, fmtlib/fmt#4707, fmtlib/fmt#4708, fmtlib/fmt#4702, fmtlib/fmt#4709). Thanks @​MathewBensonCode.

• Enabled the full Dragonbox lookup cache by default for floating-point formatting unless optimizing for binary size (__OPTIMIZE_SIZE__), giving a ~10–25% speedup. Thanks Matthias Kretz for the suggestion. Average time per double on Apple M1 Pro (clang 17, random digits, smaller is better) measured with dtoa-benchmark:

  Method	Time (ns)
  fmt (full)	22.07
  fmt (compact)	29.55
  ryu	35.21
  double-conversion	81.81
  sprintf	726.27
  ostringstream	864.34

• Improved integer formatting performance by ~3% (fmtlib/fmt#4630). Thanks @​user202729.

... (truncated)

Commits

• 1be298e Update version
• 5ea06b1 Exclude the build tree from the source package
• 11ddbcb Build docs in the release workflow so the source zip includes doc-html
• e8deaf2 Update changelog
• 128ba14 fix out-of-bounds read in basic_format_args::get (#4800)
• e60274b Run lint workflow on all PRs to fix stuck required checks
• 87bb05d Fix release workflow startup failure from insufficient permissions
• 2de684d Add .gradle directory to .gitignore (#4799)
• 1ccba0c Attach SLSA provenance to the draft instead of a new release
• c1c7296 Add a test for fmt_print
• Additional commits viewable in compare view

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

📢 Thoughts on this report? Let us know!