- PLAN-B.md §8.2 and appendix B add a batch of new runtime switches
(MOBILEGL_PIPE_PUSH / _VERIFY / _STATS / _LEGACY_MEMOS / _TEXEL_RETAIN_MB /
_INDEX_MIRROR_MB, plus MOBILEGL_IPC_* later), and §11 P0 wants them parsed beside
the existing ones. Today every knob that has to reach an Android replay costs an
edit in five files - run_android_retrace_local.py, trace-replay-ci.sh,
TraceReplayActivity's request record, the JNI marshalling, and the setenv block in
trace_replay_core.cpp. That per-knob tax is what this replaces: one extra,
`--es mobilegl_env "K=V;K=V"`, carries all of them.
- Applied last, immediately before dlopen(libMobileGL.so), so it can also override
the dedicated fields above it - MobileGL's config is read during the load, and an
escape hatch that cannot beat the defaults is not one. An entry with no '=' unsets
the variable, which is the only way to clear a default the marshalling sets.
- The existing per-knob flags stay: they carry semantics beyond a setenv (use_angle
also selects a variant, the dump lists are joined, DirectVulkan forces the
R11G11B10F fallback), and rewriting them as env strings would move that logic into
the callers.
- Surface: --env / MOBILEGL_TRACE_ENV in trace-replay-ci.sh, repeatable --env
KEY=VALUE in run_android_retrace_local.py, `mobilegl_env` intent extra,
Request::envOverrides.
- The two-level parse now lives in trace_env_overrides.hpp, beside the semicolon
splitter it shares with the texture and FBO dump lists, and
tools/trace_replay/trace_env_overrides_test.cpp pins it: the empty entries a
trailing ';' leaves behind must not become unsetenv(""), `K=` must stay a Set of
the empty string rather than an Unset (a knob read with getenv() != nullptr sees
those as opposite answers), and only the FIRST '=' may separate, or a value
carrying '=' is truncated without a word of warning. The whole MOBILEGL_PIPE_*
batch rides on this parse, and the only lane that exercised it end to end was an
on-device retrace, which would have reported a splitting bug as "the knob had no
effect".
- The check is built and RUN at build time and mobilegl_trace_replay depends on it,
so `cmake --build ... --target mobilegl_trace_replay` - the exact command of
test.yml's "Build trace replay" job, which never invokes ctest - runs it. It is
assert-free on purpose: that lane configures Release, and <cassert> under NDEBUG
would compile every check into a green run that checked nothing. Negative control:
swapping find('=') for rfind('=') fails 2 checks, and keeping the splitter's empty
entries fails 2 more.
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