test: pin task custom env query forwarding through let_value (#2239) - #2254
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ericniebler merged 1 commit intoSep 13, 2026
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…A#2239) Issue NVIDIA#2239 reported that a task whose env_type is constructed from the enclosing environment failed to compile under starts_on + let_value when the consumer provides the queried value. The bug was incidentally fixed by the task reorganization in e88b131, but without a regression test. Add two regression tests pinning the fixed behavior: the task's custom env must observe queries written by write_env, both when a let_value sits between starts_on and the task (the reported failing arrangement) and when the task is a direct child of starts_on. On pre-fix code the reported arrangement fails to compile, so these tests guard against regressions at compile time. Generated with Codebuff Co-Authored-By: Codebuff <noreply@codebuff.com>
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Hi @ericniebler — could you run /ok to test 5ffbf41 when you get a chance? It's a test-only PR adding regression coverage for #2239 (details in the description). Thanks! |
ericniebler
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Sep 13, 2026
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/ok to test 5ffbf41 |
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Adds regression tests for #2239.
What happened
Issue #2239 reported that a
stdexec::taskwhoseenv_typeis constructed from the enclosing environment failed to compile understarts_on+let_value, even when the consumer provides the queried value:The issue is already fixed on current
mainby thetaskreorganization in e88b131 (landed via #2252). I verified:main(ae89633): the reproducer compiles.7) — not the-1default — in every arrangement from the issue, including both previously failing ones.This PR
The fix landed without a regression test for this arrangement, so this adds two test-only regression tests to
test/stdexec/types/test_task.cpp:starts_on(sched, just() | let_value(task)) | write_env(prop{q, 7})— the task's env must observeq == 7.starts_on(sched, task) | write_env(...).On pre-fix code the first test fails to compile, so CI guards this behavior at compile time. The tests use
exec::single_thread_context(the existing pattern in this file) and are modules-safe (noon()).No library changes are needed.
Fixes #2239