Carry the program's version on every event (0.2.0)

[dmccoystephenson]

Every event sent by the C++ client now carries the program's own version, mirroring Stephenson-Software/trace-client-java#5.

Changes

• TraceClient takes the program's version as a required argument right after the application name:

  trace_client::TraceClient trace(baseUrl, "MyGame", MYGAME_VERSION, key, enabled, logger);

• The version is trimmed and sent as the tag version on every event (startup, command, anything else). An event's own version tag wins; the caller's Tags are never modified (the merge is done on a copy, detail::withVersion). The client has no other default tags.
• A blank version, or one over 255 bytes after trimming, is not an exception: the header promises that nothing in the client throws, and a blank base URL or application name is already handled by disabling the client with reason "unavailable". A bad version follows that same convention.
• The default-constructed (disabled) client holds the placeholder version "disabled".
• The User-Agent is unchanged and still names the client's version (trace-client-cpp/0.2.0 (<application>)).
• Breaking: TRACE_CLIENT_VERSION 0.1.0 → 0.2.0 (header banner, macro, README wire format; a VERSION 0.2.0 was added to the CMake project()). Old 3–5 argument calls fail to compile rather than silently shifting arguments (bool does not convert to std::string).
• README: example passes the version, a new "Every event carries the program's version" section, wire-format example and the disabledReason()/enabled argument notes updated. The header doc comment no longer hand-tags version on startup.

Tests

Existing tests were moved to the new signature and expected bodies; four were added: an event tagged with the trimmed version (User-Agent still the client's), an event's own version winning, the caller's tags not being mutated, and a blank/overlong version being rejected (exactly 255 bytes after trimming is accepted).

• make test (g++ 9, c++11 / c++17 / c++2a): 26 tests, 0 failed checks.
• make test-libcurl: 26 tests, 0 failed checks.
• ASan+UBSan (g++): 26 tests, 0 failed checks.
• CMake build + ctest: 1/1 passed.
• Not run locally (toolchain missing on the machine used): clang++, TSan, macOS, MSVC. CI covers these.

Mutation probes: with the version injection removed from enqueue, 3 checks failed (including the new trimmed-version test); with the merge changed to overwrite the event's own version, 2 checks failed. Both were restored.

Known nit: the class doc comment calls the version the "second argument to the constructor"; it is the third. It can be fixed in review.

🤖 Generated with Claude Code

https://claude.ai/code/session_01AuTszT2gqv7nLVYrtKD4ji

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drafted by Claude on behalf of Daniel Stephenson