feat: add --version flag with app-injected release string

[gauravharsha]

Summary

Add a first-class --version flag to the params parser, as a true sibling of --help.

• version is a native argparse flag (added next to the built-in _help in libs/argparse/argparse.h), surfaced via help_requested() / version_requested() accessors. No params-layer bolt-on, no cached pointer, no raw-argv scan.
• The library is version-agnostic: the application injects the release string via the params constructor (default "").
• --version is command-line only (like --help); it is not INI-settable.
• parse() returns false for an informational flag (--help or --version) — a stop signal. The library does not call std::exit(); the caller prints the message (on its chosen rank) and finalizes/exits. This suits the MPI programs that embed the parser.
• help_or_version() prints the release string for --version, otherwise the help text. print() / help() also emit a Version: <value> line when a version is set.
• define() rejects the reserved names help / ? / version, so a consumer parameter cannot silently shadow the built-in flags.

API

green::params::params p(description, GREEN_RELEASE);  // version injected at construction
if (!p.parse(argc, argv)) {        // false => informational flag (or args-before-defs)
  p.help_or_version();             // prints version string or help text
  // caller finalizes / exits as appropriate
}

Tests

In-process (no fork needed, since nothing exits): constructor injection round-trip, --help/--version symmetry via the accessors, help_or_version() output, the Version: line in print()/help(), --version alongside other args, and reserved-name rejection.

🤖 Generated with Claude Code

[codecov-commenter]

Codecov Report

❌ Patch coverage is 98.66667% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 91.10%. Comparing base (14d9818) to head (408dc68).
⚠️ Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
src/green/params/params.h	94.73%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main       #2      +/-   ##
==========================================
+ Coverage   90.59%   91.10%   +0.51%     
==========================================
  Files           6        6              
  Lines         999     1068      +69     
==========================================
+ Hits          905      973      +68     
- Misses         94       95       +1     

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[Copilot]

Pull request overview

Adds a reusable --version flag to the green::params::params argument parser, allowing applications to inject a release string and have the parser print it and exit successfully when requested.

Changes:

• Registers a new --version flag in params and adds set_version() / version() APIs.
• Implements version print-and-exit behavior during parsing.
• Adds unit tests for the version string round-trip and the --version exit behavior (via fork/pipe capture).

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 4 comments.

File	Description
src/green/params/params.h	Adds the --version flag registration, version storage/accessors, and version handling in parse().
test/params_test.cpp	Adds tests for version setter/getter and end-to-end --version output/exit behavior.

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[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 5 comments.

[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 5 comments.

[gauravharsha]

Wasn't happy with initial implementation. Now updated and cleaner.
@egull requesting your review once again.

[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated 6 comments.

Comments suppressed due to low confidence (1)

src/green/params/params.h:312

• parse(const std::string&) allocates argv via get_argc_argv() (which uses new[]) but never frees it, leaking memory on every call (including in tests that parse repeatedly). Free the allocated array after parse(argc, argv) returns.

    bool parse(const std::string& s) {
      std::string to_parse = s;
      auto [argc, argv]    = get_argc_argv(to_parse);
      return parse(argc, argv);
    }

[egull]

This looks like it's over-engineering. But fine, we can do it.

[egull]

Fine. Lots of engineering for a bit of parameter parsing, but it works.

[egull]

This looks like it's over-engineering. But fine, we can do it.

[Copilot]

Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

Comments suppressed due to low confidence (1)

src/green/params/params.h:317

• parse(const std::string&) leaks the argv array allocated by get_argc_argv(). This can accumulate in long-running processes or in repeated in-process parses/tests. Use RAII (or delete[]) to ensure the allocated char** is freed even if parse(argc, argv) throws.

    bool parse(const std::string& s) {
      std::string to_parse = s;
      auto [argc, argv]    = get_argc_argv(to_parse);
      return parse(argc, argv);
    }