The build modules' fetch step says which changed files are compiled programs, so the checker can refuse them (issue 1577)

modules/mesh-build-node/cmd/mesh-build-node/fetch.go

@@ -51,11 +51,13 @@ type FetchResult struct {
 	// commit, the merge commit of the head onto it, the paths the merge changes and the tree of each module directory.
 	// A head that does not merge cleanly is an answer: Merge is empty, Conflicts names the files, and the workspace is
 	// left at the trunk commit with nothing installed.
-	Base      string                          `json:"base,omitempty"`
-	Merge     string                          `json:"merge,omitempty"`
-	Conflicts []string                        `json:"conflicts,omitempty"`
-	Changed   []string                        `json:"changed,omitempty"`
-	Trees     map[string]buildstep.ModuleTree `json:"trees,omitempty"`
+	Base      string   `json:"base,omitempty"`
+	Merge     string   `json:"merge,omitempty"`
+	Conflicts []string `json:"conflicts,omitempty"`
+	Changed   []string `json:"changed,omitempty"`
+	// Programs are the changed files that are compiled programs (issue 1577); a merge answers it, a pointer to an empty list when there are none, absent for a fetch that made no merge.
+	Programs *[]buildstep.Program            `json:"programs,omitempty"`
+	Trees    map[string]buildstep.ModuleTree `json:"trees,omitempty"`
 	// Group is the group's package the fetch packed and served to the TypeScript members (the call's `package`):
 	// "<name>@<version> <integrity>".
 	Group string `json:"group,omitempty"`

modules/mesh-build-node/cmd/mesh-build-node/preview.go

@@ -27,6 +27,9 @@ func (m *Module) merge(ctx context.Context, run forgekey.Runner, res *FetchResul
 	}
 	res.Base = mr.Base
 	res.Conflicts, res.Merge, res.Changed = mr.Conflicts, mr.Merge, mr.Changed
+	if mr.Merge != "" {
+		res.Programs = &mr.Programs
+	}
 	if res.Merge == "" {
 		return nil
 	}