ci: enforce the name equality rules/mcpp.toml calls load-bearing - #7
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rules/mcpp.toml states that the package name and the module name are kept EQUAL, and that this is what makes the package work on every engine rather than on the newest one. Nothing enforced it. The check next to this one compares the three versions, which is a different invariant. mcpp before 2026.8.29.1 registers a host module under the dependency's `package.name`; from that release it uses the name the interface declares. Only equality satisfies both. The break is asymmetric, so one compiler cannot reveal it: renaming either alone still builds under GCC, which locates a BMI by its declared name through gcm.cache, and fails under Clang and MSVC, which are handed an explicit `<name>=<bmi>` mapping built from the registered name. A consumer on an older engine would see this package work on one compiler and not on the others. Both names are read in a single awk rather than a `sed | head -1` pipeline, so a successful match cannot be reported as 141 through SIGPIPE under `pipefail`, and an empty result fails instead of passing -- an extractor that matched nothing would otherwise report success on a file it never parsed. Comment lines begin with `#` and match neither pattern, so the prose in this very file that explains the rule cannot answer the assertion. Measured: passes on the current tree, red when the package name is changed, green again once restored.
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rules/mcpp.tomlstates that the package name and the module name are keptEQUAL, and that this is what makes the package work on every engine rather
than on the newest one. Nothing enforced it — the check beside this one
compares the three versions, which is a different invariant.
mcpp before 2026.8.29.1 registers a host module under the dependency's
package.name; from that release it uses the name the interface declares.Only equality satisfies both.
The break is asymmetric, so a single compiler cannot reveal it: renaming
either name alone still builds under GCC, which locates a BMI by its declared
name through
gcm.cache, and fails under Clang and MSVC, which are handed anexplicit
<name>=<bmi>mapping built from the registered name.What the check avoids
sed | head -1: underpipefailthe writer can take SIGPIPE and report141 for a successful match. Both names are read in one
awk.#and match neither pattern, so the prose in thisfile that explains the rule cannot answer the assertion.
Measurement
package.namechangedThe same guard is proposed for
mcpplibs/clangtidyin its PR #1.