Move a module on a merge only when its build source holds a changed file (hq ADR 0267, issue 363)

Every merge to the controller's repository planned the controller, the
build seat's holder and the route proxy in three gated tiers, whatever it
changed (issue 338). The planner now maps a merge's files onto the build
source each module's newest trunk build said: a README moves nothing, the
controller's command the controller alone, the proxy's program the proxy
alone. A module with none said, or one an open plan has yet to build, is
read whole as before. Sharing a repository draws no packages edge any more,
and one recorded before neither widens nor orders a plan.

internal/inventory/builds_test.go

@@ -2,6 +2,7 @@ package inventory
 
 import (
 	"context"
+	"reflect"
 	"strings"
 	"testing"
 )
@@ -169,3 +170,47 @@ func TestWhatABuildReadComesBackForTheNewestBuildOfEachModule(t *testing.T) {
 		t.Fatal("a failed build's reading was kept as what that module reads")
 	}
 }
+
+// **What a build said it was made from comes back laid over what it read** (novox/hq ADR 0267): a context's
+// paths on its entry, the module's own as an entry marked Own — and never in the stored `built_contexts`,
+// where a controller that predates them would read an own entry as a context of its own repository.
+func TestABuildsBuildSourceComesBackOverWhatItRead(t *testing.T) {
+	inv := fresh(t)
+	ctx := context.Background()
+	said := aBuild("said", "route-proxy", "")
+	said.Read = []ReadRepository{{Repository: "novox/mesh-controller", Ref: "main"}, {Repository: "novox/other"}}
+	said.Sources = []BuildSource{
+		{Paths: []string{"modules/route-proxy/Dockerfile", "modules/route-proxy/module.json"}},
+		{Repository: "novox/mesh-controller", Ref: "main", Paths: []string{"examples/route-proxy/", "go.mod"}},
+		{Repository: "novox/unread", Paths: []string{"x"}},
+	}
+	unsaid := aBuild("unsaid", "build-agent", "")
+	unsaid.Read = []ReadRepository{{Repository: "novox/mesh-controller", Ref: "main"}}
+	for _, b := range []Build{said, unsaid} {
+		if err := inv.RecordBuild(ctx, b); err != nil {
+			t.Fatal(err)
+		}
+	}
+	read, err := inv.ReadRepositories(ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+	want := []ReadRepository{
+		{Repository: "novox/mesh-controller", Ref: "main", Paths: []string{"examples/route-proxy/", "go.mod"}},
+		{Repository: "novox/other"},
+		{Paths: []string{"modules/route-proxy/Dockerfile", "modules/route-proxy/module.json"}, Own: true},
+	}
+	if !reflect.DeepEqual(read["route-proxy"], want) {
+		t.Fatalf("read back %+v\nwanted %+v", read["route-proxy"], want)
+	}
+	if got := read["build-agent"]; len(got) != 1 || got[0].Paths != nil || got[0].Own {
+		t.Fatalf("a build that said no build source reads as %+v", got)
+	}
+	var stored string
+	if err := inv.store.Pool().QueryRow(ctx, `select built_contexts::text from build where id = 'said'`).Scan(&stored); err != nil {
+		t.Fatal(err)
+	}
+	if strings.Contains(stored, "paths") || strings.Contains(stored, "own") {
+		t.Fatalf("the build source was stored among what the build read: %s", stored)
+	}
+}