touchedBy is now the only mapping of changed files onto modules — touched, added, and
read by no build — and reachOfMerge the planner's whole answer with the dependency walk.
The merge handler, the plan what-if, the merge gate's width and composition, and a pull
request's check all ask it, so planning and gating cannot disagree. The gate composes
the definitions of the modules a merge would rebuild or add, not every one in the tree,
and the check says the dependents a merge would build after them.
The builder reads a module's own directory (the repository for one built from its root)
and a repository its recipe packages, nothing else. A file in no module's directory was
read as shared code and rebuilt everything built from the repository: 103 modules for a
merge-check.sh added at the catalogue's root. It now touches nothing, in the merge
handler, the release planner and the pull request's check alike, and the gate says so.
Every pull request the forge announces is mapped onto the mesh's module graph by the
merge handler's rule (issue 278): touching a module — or adding one — runs the gate
(mesh/merge-gate), its judge chosen by the graph (the controller judges itself, the
node-engine by its validator); a repository of the mesh that touches none runs only its
own merge-check.sh (mesh/repo-check), a warning when it has none. Nothing is left pending:
a repository outside the mesh touching nothing is told so as a pass.
The gate moves out of the per-repository scripts into the build seat, so a script is the
repository's own tests and declares its toolchain (go or typescript). The controller's
manifest names every verb of its seat again (ADR 0132), held by a test.
jochen