Leave out a dependent of a base that came out the same, and end a walk with every build the same as done (ADR 0267 rule 3; hq issues 607, 611, 721)

cmd/mesh-controller/same_program_test.go

@@ -1,7 +1,10 @@
 package main
 
 import (
+	"context"
+	"strings"
 	"testing"
+	"time"
 
 	"github.com/novox/mesh-controller/internal/inventory"
 	"github.com/novox/mesh-controller/internal/link"
@@ -65,3 +68,67 @@ func TestAWalkLeavesOutAModuleWhoseProgramDidNotChange(t *testing.T) {
 		t.Fatalf("a walk answering a merge without a pull request left out %v", same)
 	}
 }
+
+// TestADependentOfABaseThatCameOutTheSameIsLeftOut is ADR 0267 rule 3 (novox/hq issue 607): a dependent is in a walk
+// for its base; when the base comes out the same as the build the mesh holds, the dependent stands on that build
+// still, and leaves the walk with it — and so does a dependent of that dependent. One a merge moves itself stays.
+func TestADependentOfABaseThatCameOutTheSameIsLeftOut(t *testing.T) {
+	edges := []inventory.Edge{{From: "app", To: "base", Kind: inventory.EdgeDeclared},
+		{From: "app2", To: "app", Kind: inventory.EdgeDeclared}, {From: "own", To: "base", Kind: inventory.EdgeDeclared}}
+	plan := &inventory.Plan{Modules: map[string]*inventory.PlanModule{"base": {}, "app": {}, "app2": {}, "own": {}}}
+	same := withDependentsOf(map[string]string{"base": "unchanged: its program is the same"}, plan,
+		[]string{"base", "own"}, edges)
+	if !strings.Contains(same["app"], "only for base") || !strings.Contains(same["app2"], "only for app") {
+		t.Fatalf("the dependents of a base that came out the same are not left out: %v", same)
+	}
+	if _, left := same["own"]; left {
+		t.Fatalf("a module its merge moves itself is left out for its base: %v", same)
+	}
+	// A dependent of a base that still moves stays.
+	edges = append(edges, inventory.Edge{From: "app", To: "own", Kind: inventory.EdgeDeclared})
+	same = withDependentsOf(map[string]string{"base": "unchanged"}, plan, []string{"base", "own"}, edges)
+	if _, left := same["app"]; left {
+		t.Fatalf("a dependent of a base that still moves is left out: %v", same)
+	}
+}
+
+// Against the store, the path a real merge takes (novox/hq issues 721 and 611): a merge whose check built its one
+// module the same as the build the mesh holds is cut into a walk done with nothing to walk, whose record names the
+// module unchanged and why — the walk mesh-delivery reads as delivered, never stranded.
+func TestAWalkWhoseEveryBuildCameOutTheSameIsDone(t *testing.T) {
+	open := windowed(t)
+	endsItsLine(t)
+	asksRecorded(t)
+	ctx := t.Context()
+	inv := open.inventory
+	if err := inv.RecordBuild(ctx, inventory.Build{ID: "build-one", Repository: "novox/one", Ref: "main",
+		Module: "one", Commit: "c0", On: "builder", Asked: t0.Add(-time.Hour),
+		Made:    []inventory.Artifact{{Name: "one", Kind: "image", Reference: "store/one@sha256:aaaa"}},
+		Sources: []inventory.BuildSource{{Paths: []string{"main.go", "go.mod"}}}}); err != nil {
+		t.Fatal(err)
+	}
+	pull := link.PullRef{Owner: "novox", Repo: "one", Number: 7}
+	was := checkedBuildsOf
+	checkedBuildsOf = func(context.Context, []link.PullRef) ([]link.CheckedBuild, error) {
+		return []link.CheckedBuild{{Pull: pull, Head: "headaaaaaaaa", Built: link.CheckBuilt{Module: "one", Key: "k",
+			Made:   []link.MadeArtifact{{Name: "one", Kind: "image", Reference: "scratch/one@sha256:bbbb"}},
+			Same:   "unchanged: its program is the same as running build one aaaa",
+			SameAs: map[string]string{"one": "10.0.0.1:5000/one@sha256:aaaa"}}}}, nil
+	}
+	t.Cleanup(func() { checkedBuildsOf = was })
+	code := repoMerge("one", "one1aaaaaaaa", t0)
+	code.Number, code.HeadSHA = 7, "headaaaaaaaa1111"
+	hear(t, open, code, t0.Add(time.Second))
+	cutAt(t, open, t0.Add(2*time.Minute))
+	ws, _ := walks(t, open)
+	if len(ws) != 1 {
+		t.Fatalf("walks: %+v", ws)
+	}
+	w := ws[0]
+	if w.State != inventory.PlanDone || len(w.Tiers) != 0 || len(w.Modules) != 0 {
+		t.Fatalf("the walk reads %s, tiers %v, modules %v; want done with nothing to walk", w.State, w.Tiers, w.Modules)
+	}
+	if w.Delivery == nil || !strings.Contains(w.Delivery.Unchanged["one"], "its program is the same as running build") {
+		t.Fatalf("the walk does not say one matched what runs: %+v", w.Delivery)
+	}
+}