feat(gitops): report the generation a render declared

The prior generation comes from the tree the render replaces, and that
tree is per module, not per environment: rendering another environment
replaces it whole, so rendering staging and then production again finds
no prior production document and starts at 1 — which the production host
refuses as stale.

Inventing a number the renderer cannot know would be worse, so the render
reports the generation it declared instead. A reset is then visible where
it happens rather than at the host.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

Author: antoinetoussaint-byte

cmd/deploy/gitops.go

@@ -447,8 +447,8 @@ func printElidedNamespaces(elided []string) {
 // environment names no host both render zero bindings, and only this tells
 // them apart.
 func printSolutionHostBindings(result *gitops.RenderResult) {
-	for _, path := range result.SolutionHostBindings {
-		cli.Info("Declared solution host binding %s", path)
+	for _, declared := range result.SolutionHostBindings {
+		cli.Info("Declared solution host binding %s at generation %d (%s)", declared.Binding, declared.Generation, declared.Path)
 	}
 	if len(result.UndeclaredSolutions) == 0 {
 		return

docs/solution-host-bindings.md

@@ -139,6 +139,13 @@ avoid it would be a renderer asserting a history it does not have.
 
 An unreadable delivered document is an error, never a silent reset to 1.
 
+The sharp edge: the render destination is per **module**, not per environment,
+and a render replaces it whole. Rendering staging and then production again
+finds no prior production document and starts over at 1. The render prints the
+generation it declared for exactly this reason — a reset is otherwise
+invisible until the host refuses the document. Render an environment from a
+checkout that holds that environment's delivered tree.
+
 ## Release digest
 
 Empty in v1, and left empty deliberately. Signed releases do not exist yet; a

pkg/gitops/solution_host_binding.go

@@ -152,7 +152,7 @@ type SolutionModulePin struct {
 // validateTree so the ConfigMaps it writes are held to the same promotable
 // ruleset as everything else in the tree, and before buildInventory so they are
 // hashed into the render digest like any other delivered file.
-func renderSolutionHostBindings(owned, destination string, opts *RenderOptions) ([]string, error) {
+func renderSolutionHostBindings(owned, destination string, opts *RenderOptions) ([]DeclaredSolutionHostBinding, error) {
 	if len(opts.SolutionInstances) == 0 {
 		return nil, nil
 	}
@@ -188,14 +188,16 @@ func renderSolutionHostBindings(owned, destination string, opts *RenderOptions)
 	if _, err := (solutionhost.Host{}).Admit(documents...); err != nil {
 		return nil, fmt.Errorf("rendered solution host bindings are not admissible: %w", err)
 	}
-	written := make([]string, 0, len(documents))
+	written := make([]DeclaredSolutionHostBinding, 0, len(documents))
 	names := make([]string, 0, len(documents))
 	for index, document := range documents {
 		relative, err := writeSolutionHostBinding(owned, opts, document, instances[index].Alias)
 		if err != nil {
 			return nil, err
 		}
-		written = append(written, relative)
+		written = append(written, DeclaredSolutionHostBinding{
+			Path: relative, Binding: document.Binding, Generation: document.Generation,
+		})
 		names = append(names, document.Binding+".yaml")
 	}
 	if err := writeSolutionHostBindingKustomization(owned, opts.Environment, names); err != nil {

pkg/gitops/solution_host_binding_test.go

@@ -99,8 +99,13 @@ func TestRenderDeclaresOneBindingPerSolutionInstance(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	if len(result.SolutionHostBindings) != 1 || result.SolutionHostBindings[0] != "solution-host-bindings/overlays/prod/obin.prod.crm.yaml" {
-		t.Fatalf("rendered bindings %v", result.SolutionHostBindings)
+	if len(result.SolutionHostBindings) != 1 {
+		t.Fatalf("rendered bindings %+v", result.SolutionHostBindings)
+	}
+	declared := result.SolutionHostBindings[0]
+	if declared.Path != "solution-host-bindings/overlays/prod/obin.prod.crm.yaml" ||
+		declared.Binding != "obin.prod.crm" || declared.Generation != 1 {
+		t.Fatalf("declared binding %+v", declared)
 	}
 	if len(result.UndeclaredSolutions) != 0 {
 		t.Fatalf("declared a host yet reported undeclared solutions %v", result.UndeclaredSolutions)
@@ -279,7 +284,7 @@ func TestRenderDeclaresNoBindingWithoutADeclaredHost(t *testing.T) {
 		t.Fatal(err)
 	}
 	if len(result.SolutionHostBindings) != 0 {
-		t.Fatalf("a binding was rendered with no host: %v", result.SolutionHostBindings)
+		t.Fatalf("a binding was rendered with no host: %+v", result.SolutionHostBindings)
 	}
 	// Silence is not the report: the render says which solution it could not
 	// declare, so an operator can tell this from a composition with none.
@@ -383,7 +388,7 @@ func TestRenderRefusesAMixedReleaseSet(t *testing.T) {
 	options.SolutionInstances[0].Package = "obin/crm"
 	result, err := RenderOwnedTree(context.Background(), options, renderWorkload(pinnedDeployment))
 	if err != nil {
-		t.Fatalf("two artifacts of one release were refused: %v (%v)", err, result.SolutionHostBindings)
+		t.Fatalf("two artifacts of one release were refused: %v (%+v)", err, result.SolutionHostBindings)
 	}
 	document := deliveredBinding(t, destination, "obin.prod.crm")
 	for _, artifact := range document.Artifacts {
@@ -458,7 +463,7 @@ func TestRenderSolutionDeclaresItsOwnPresence(t *testing.T) {
 		t.Fatalf("RenderSolution: %v", err)
 	}
 	if len(result.SolutionHostBindings) != 1 {
-		t.Fatalf("rendered bindings %v (undeclared %v)", result.SolutionHostBindings, result.UndeclaredSolutions)
+		t.Fatalf("rendered bindings %+v (undeclared %v)", result.SolutionHostBindings, result.UndeclaredSolutions)
 	}
 	document := deliveredBindingIn(t, result.Path, "local", "hello.local.lastlogin-go")
 	if document.Host.Coordinate != "obin/local/dev" {
@@ -596,9 +601,9 @@ func TestRenderedTreeDeliversItsBindings(t *testing.T) {
 	if !strings.Contains(string(kustomization), "obin.prod.crm.yaml") {
 		t.Fatalf("the kustomization does not name the delivered document:\n%s", kustomization)
 	}
-	for _, path := range result.SolutionHostBindings {
-		if !strings.HasPrefix(path, solutionHostBindingOverlay("prod")+"/") {
-			t.Fatalf("binding %q is outside the overlay Argo delivers", path)
+	for _, declared := range result.SolutionHostBindings {
+		if !strings.HasPrefix(declared.Path, solutionHostBindingOverlay("prod")+"/") {
+			t.Fatalf("binding %q is outside the overlay Argo delivers", declared.Path)
 		}
 	}
 }
@@ -644,3 +649,58 @@ func TestReleaseIdentityRefusesAPackageItCannotName(t *testing.T) {
 		t.Fatalf("releaseIdentity = %q, %q, %v", publisher, name, err)
 	}
 }
+
+// TestRenderingAnotherEnvironmentResetsTheGeneration pins the sharp edge of
+// taking the prior generation from the delivered tree. The render destination
+// is per module and NOT per environment, and a render replaces it whole, so
+// rendering staging and then production again finds no prior production
+// document and starts over at 1 — which the production host correctly refuses
+// as stale.
+//
+// It is a test rather than a note because the behaviour is load-bearing: the
+// alternative, inventing a generation the renderer cannot know, is worse. The
+// render reports the generation it declared so the reset is visible where it
+// happens.
+func TestRenderingAnotherEnvironmentResetsTheGeneration(t *testing.T) {
+	destination := filepath.Join(t.TempDir(), "modules", "crm")
+	production := solutionRenderOptions(destination)
+	changed := strings.Replace(pinnedDeployment, "name: api\nspec:", "name: api\n  labels:\n    v: \"2\"\nspec:", 1)
+	for _, body := range []string{pinnedDeployment, changed} {
+		if _, err := RenderOwnedTree(context.Background(), production, renderWorkload(body)); err != nil {
+			t.Fatal(err)
+		}
+	}
+	if advanced := deliveredBinding(t, destination, "obin.prod.crm").Generation; advanced != 2 {
+		t.Fatalf("production reached generation %d, want 2", advanced)
+	}
+
+	staging := solutionRenderOptions(destination)
+	staging.Environment = "staging"
+	staging.SolutionInstances[0].Units[0].Path = "services/api"
+	stagingRender := func(_ context.Context, root string) error {
+		overlay := filepath.Join(root, "services", "api", "overlays", "staging")
+		if err := os.MkdirAll(overlay, 0o755); err != nil {
+			return err
+		}
+		return os.WriteFile(filepath.Join(overlay, "deployment.yaml"), []byte(pinnedDeployment), 0o644)
+	}
+	if _, err := RenderOwnedTree(context.Background(), staging, stagingRender); err != nil {
+		t.Fatal(err)
+	}
+	// The whole owned tree was replaced, production's document with it.
+	if _, err := os.Stat(filepath.Join(destination, filepath.FromSlash(solutionHostBindingOverlay("prod")))); !os.IsNotExist(err) {
+		t.Fatalf("production's overlay survived a staging render: %v", err)
+	}
+	result, err := RenderOwnedTree(context.Background(), production, renderWorkload(changed))
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got := deliveredBinding(t, destination, "obin.prod.crm").Generation; got != 1 {
+		t.Fatalf("production resumed at generation %d; the prior document was gone, so 1 is the honest answer", got)
+	}
+	// And the render says so, rather than leaving the reset to be discovered
+	// when the host refuses the document.
+	if len(result.SolutionHostBindings) != 1 || result.SolutionHostBindings[0].Generation != 1 {
+		t.Fatalf("the render did not report the generation it declared: %+v", result.SolutionHostBindings)
+	}
+}

pkg/gitops/types.go

@@ -278,10 +278,10 @@ type RenderResult struct {
 	// ClearedDev are the dev deployments the tree this render replaced carried.
 	// A full render re-derives every image, so they no longer run.
 	ClearedDev []InventoryDevDeployment `json:"clearedDev,omitempty"`
-	// SolutionHostBindings are the tree-relative paths of the rendered
-	// SolutionHostBinding documents: what this render declares should be
-	// present on the host, one per solution instance.
-	SolutionHostBindings []string `json:"solutionHostBindings,omitempty"`
+	// SolutionHostBindings are the SolutionHostBinding documents this render
+	// declared: what it says should be present on the host, one per solution
+	// instance.
+	SolutionHostBindings []DeclaredSolutionHostBinding `json:"solutionHostBindings,omitempty"`
 	// UndeclaredSolutions are the solution instances this render delivered
 	// workloads for but declared no binding for, because the environment names
 	// no host. It is reported rather than inferred from an empty list: a
@@ -290,6 +290,22 @@ type RenderResult struct {
 	UndeclaredSolutions []string `json:"undeclaredSolutions,omitempty"`
 }
 
+// DeclaredSolutionHostBinding is one rendered binding document: where it was
+// written, which binding it declares, and at which generation.
+//
+// The generation is reported rather than left in the file because a reset is
+// otherwise invisible. The prior generation comes from the tree this render
+// replaced, and that tree is per module and not per environment — rendering
+// another environment replaces it whole. So rendering staging and then
+// production again finds no prior production document and starts at 1, which
+// the production host refuses as stale. Printing the generation is what turns
+// that into something an operator sees at the render instead of at the host.
+type DeclaredSolutionHostBinding struct {
+	Path       string `json:"path"`
+	Binding    string `json:"binding"`
+	Generation uint64 `json:"generation"`
+}
+
 type PublishRequest struct {
 	Module          string
 	Environment     string