MGS1101: this VCS backend cannot answer that
magus asked the configured version-control backend a question it does not implement, so the feature reports a gap instead of an answer.
[MGS1101] hg does not report branch changes
Nothing failed. The command still ran, and everything that did not depend on the missing capability is correct.
Why
magus talks to version control through a backend registry rather than shelling out to one tool, so a workspace can be on git, hg, or something a plugin provides. Backends are not required to be equal: a capability exists when a backend can answer it, and a backend that cannot is a normal state rather than a broken install.
The reason this is a diagnostic at all is that the alternative is silence, and silence is indistinguishable from good news. The branch-overlap lookup is the clearest case:
- "No other branch is changing these files" is reassurance. You can stop thinking about it.
- "This backend cannot tell you which branches are changing these files" is a gap in what magus knows.
Both render as an empty list. Only one of them means you are safe, so magus
names the gap rather than letting an empty result speak for it. That is the same
reason a knowledge lookup distinguishes absent from unknown: a negative claim
is a claim, and magus does not make one it cannot support.
Fix
There is usually nothing to fix in your workspace. A capability gap is a fact about the backend, not a misconfiguration.
- Check that the backend is the one you meant.
magus buzz -e 'import "std"; import "vcs"; fun main() > void { std\print(vcs\metadata()); } main();'reports which backend resolved for this tree. - Treat what the lookup would have covered as unmeasured, not as clear. Where magus says a lookup is unsupported, do the check by hand if it matters to the change in front of you.
- Implement it, if you own the backend. The capability interfaces are small and additive: a backend advertises what it can do by satisfying one, and magus reports this code for the rest. See Review for how the Diff page consumes them.