All notable changes to this project are documented in this file.

[1.0.0] - 2026-05-06

First stable release of clap, consolidating all work completed since the project was created.

Added

Added the core parser with positional arguments, options, subcommands, and namespace-based parse results.
Added built-in actions for storing values, storing constants, booleans, counters, append-style accumulation, help, version, and custom handlers.
Added built-in type conversion for strings, integers, floats, and booleans, plus custom type registration.
Added mutually exclusive groups, argument dependencies, display groups, and user data attachment for richer argument modeling.
Added abbreviated long-option matching, bundled short options, and flexible nargs support including optional, repeated, remainder, and parser forms.
Added automatic usage and help formatting with grouping, wrapping, and alignment support.
Added clap_parse_result_t return handling, structured error accessors, and helper APIs such as clap_namespace_has() and clap_argument_data().
Added custom allocator support, internal safe buffer utilities, symbol visibility controls, CMake package export, pkg-config metadata, and Windows DLL/static build support.
Added comprehensive unit, integration, tokenizer, short-option bundle, fuzz, and abbreviation coverage in the test suite.
Added CI support for coverage, sanitizer, and multi-platform validation workflows.

Reworked parsing internals into tokenizer, pattern, and state-machine stages to improve maintainability.
Changed parse flow to return clap_parse_result_t instead of calling exit(0).
Stored float defaults as native numeric values instead of string representations.
Propagated default conversion failures instead of silently ignoring them.
Resolved custom type handlers from the parser registry and made the registry the single source of truth for built-in handlers.
Reduced public API exposure by hiding internal structs and trimming implementation details from installed headers and generated docs.
Cleaned up mutex-group API usage and display-group naming to make the public interface more consistent.
Standardized help output formatting, including the capitalized Usage heading.

Fixed parsing for fixed-arity positional arguments and optional arguments with fixed nargs.
Fixed option value theft when multiple options shared the same destination.
Fixed handling of negative numbers so they can be consumed as option values when appropriate.
Fixed float merging in namespace merge paths.
Fixed mutex-group conflict reporting and excluded auto-generated help arguments from mutex groups.
Fixed subparser program-name extraction and display-group indentation in generated help output.
Fixed Windows build and installation issues around CLAP_STATIC, symbol export/import, and packaging.
Fixed missing POSIX feature test macros in test targets.
Fixed a non-existent clap_argument_depends_on API reference.
Fixed fuzz and sanitizer findings, including const_value buffer leaks, tokenized long-option leaks, and related harness cleanup.
Added defensive NULL checks after type resolution and addressed MSVC static-analysis warnings including C4200, C6011, and C6031-related issues.
Fixed Doxygen warnings and missing struct documentation.

Reworked the README for accuracy, install guidance, examples, badges, and API usage notes.
Added comprehensive Doxygen documentation and CI generation for API docs.
Expanded error-handling examples and completed the custom_type example description.
Added and refined documentation around display groups, Windows static linking, and general usage behavior.

Added coverage XML generation and Codecov integration updates.
Hardened fuzzing workflows, preserved libFuzzer exit codes, and created artifact output handling.
Added ASan + UBSan CI coverage and fixed sanitizer job link issues.
Added Windows-specific CI safeguards for timeout-sensitive tests.
Removed stale coverage cache handling that caused .gcno CI failures.

Improved formatter implementation readability and maintainability.
Removed unused trie and arena modules.
Removed dead code discovered during cleanup and sanitizer work.
Applied general build, docs, and repository hygiene fixes made during early project setup.