A merge says which files it changed

Every module built from a repository was rebuilt for a change to any of them: one merge in this
repository meant twenty-six builds, which is what exhausted a public registry's pull limit. The
forge lists the files a merge changed and the event carries them, from the watcher and from the
merge tool alike; a merge that changed more files than were asked for says so, and the mesh then
treats the whole repository as changed rather than guessing.

modules/gitea/index.ts

@@ -95,6 +95,10 @@ async function pollMerged(client: GiteaClient): Promise<void> {
       // at once.
       const fresh = !!pull.merged_at && !!since && pull.merged_at > since;
       if (primedMerges && fresh) {
+        // What it changed, asked for only now: a module is rebuilt because a file inside its own
+        // directory moved, and without this every module built from a repository is rebuilt for a
+        // change to any of them (novox/hq 04-ISSUES/131).
+        const changed = await client.listPullFiles(repo.owner, repo.name, pull.number);
         await emit("pull.merged", {
           owner: repo.owner,
           repo: repo.name,
@@ -106,6 +110,8 @@ async function pollMerged(client: GiteaClient): Promise<void> {
           merged_at: pull.merged_at,
           clone_url: repo.clone_url,
           html_url: pull.html_url,
+          paths: changed.paths,
+          paths_truncated: changed.truncated,
         });
         // Said, because a trigger that fires silently is indistinguishable from one that did not
         // fire (novox/hq 04-ISSUES/131) — this line is how an operator knows the mesh was told.