Run the integration tests in the merge check, resolve file references in the hand apply, refuse an unresolved one, and read an object by name without listing the bucket (issue 1695)

cmd/mesh-host/file_references_test.go

@@ -59,3 +59,34 @@ func TestADeclarationWithAFileByDigestAppliesFromTheObject(t *testing.T) {
 		t.Errorf("1695/AC1: the file holds %d bytes (%v), want %d", len(got), err, len(body))
 	}
 }
+
+// 1695/AC8: the hand-run `apply <file>` and `reconcile` have no bus: a reference whose file here verifies is applied
+// as it is, any other refuses and writes nothing — never an empty file.
+func TestTheHandApplyNeverWritesAReferenceEmpty(t *testing.T) {
+	unansweringPacman(t)
+	body := []byte(strings.Repeat("a line of a big file\n", 4000))
+	dir := t.TempDir()
+	target := filepath.Join(dir, "big")
+	opts := options{state: filepath.Join(dir, "state.json"), out: &strings.Builder{}}
+	raw := referenceDeclaration(target, body)
+	d, err := declaration.ParseFileTrusted(raw)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err := runApply(context.Background(), opts, d, raw, fromFile); err == nil || !strings.Contains(err.Error(), "digest") {
+		t.Errorf("1695/AC8: a reference with no file and no bus was not refused: %v", err)
+	}
+	if _, err := os.Stat(target); err == nil {
+		t.Error("1695/AC8: a file was written for a reference that could not be had")
+	}
+	if err := os.WriteFile(target, body, 0o644); err != nil {
+		t.Fatal(err)
+	}
+	d, _ = declaration.ParseFileTrusted(raw)
+	if err := runApply(context.Background(), opts, d, raw, fromFile); err != nil && !strings.Contains(err.Error(), "applied only in part") {
+		t.Fatalf("1695/AC8: %v", err)
+	}
+	if got, _ := os.ReadFile(target); string(got) != string(body) {
+		t.Errorf("1695/AC8: the file holds %d bytes, want %d", len(got), len(body))
+	}
+}

cmd/mesh-host/main.go

@@ -608,6 +608,12 @@ func runApply(ctx context.Context, opts options, d *declaration.Declaration, raw
 		return errors.New(olderGenerationWords(*refused))
 	}
 
+	// A file given by digest is had before the plan is drawn from it (novox/hq ADR 0486 §1, issue 1695). This command has
+	// no link to the bus, so a file already here that verifies is used, and any other is refused: never written empty.
+	if err := apply.ResolveFileReferences(ctx, d, link.FilesFrom(ctx)); err != nil {
+		return fmt.Errorf("a file of this declaration could not be had by its digest: %w", err)
+	}
+
 	// Said before anything is done.
 	steps := apply.Plan(d, known, origin)
 	if opts.json && opts.dryRun {
@@ -2070,13 +2076,6 @@ func applyAndKeepHeld(ctx context.Context, opts options, raw []byte, signed *sto
 		return link.Report{Refused: err.Error()}
 	}
 	order := link.Order{Epoch: declared.Epoch, Sequence: declared.Sequence}
-	// **A file given by digest is fetched and verified before anything of the declaration is applied** (novox/hq ADR
-	// 0486 §1, issue 1695): one object missing or differing refuses the declaration whole. The signed bytes are what is
-	// kept; only what is applied has the content in place of the reference.
-	if err := apply.ResolveFileReferences(ctx, declared, link.FilesFrom(ctx)); err != nil {
-		return link.Report{Declared: digestOf(raw), Order: order,
-			Refused: "a file of this declaration could not be had by its digest: " + err.Error()}
-	}
 
 	// **Older than what this node applied is refused, before anything is read from the machine**
 	// (novox/hq to-be 45 §6, ADR 0227 rule 2): a controller that lost its lease and goes on sending.
@@ -2121,6 +2120,14 @@ func applyAndKeepHeld(ctx context.Context, opts options, raw []byte, signed *sto
 		known.Mode = apply.ModeOf(declared)
 	}
 
+	// **A file given by digest is fetched and verified before anything of the declaration is applied** (novox/hq ADR
+	// 0486 §1, issue 1695): one object missing or differing refuses the declaration whole. The signed bytes are what is
+	// kept; only what is applied has the content in place of the reference.
+	if err := apply.ResolveFileReferences(ctx, declared, link.FilesFrom(ctx)); err != nil {
+		return link.Report{Declared: digestOf(raw), Order: order,
+			Refused: "a file of this declaration could not be had by its digest: " + err.Error()}
+	}
+
 	built, err := system.For(builtFor)
 	if err != nil {
 		return link.Report{Refused: err.Error()}