feat(pack): the declared completion mode reaches the configuration digest

Two packages differing only in how their answer arrives are called the same way
and answered differently, so a digest that ignored the mode would call them the
same package.

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

Author: antoinetoussaint-byte

pkg/pack/pack.go

@@ -132,9 +132,14 @@ func ConfigurationDigest(runnable *resources.Runnable) (string, error) {
 	}{
 		Configurations: append([]string{}, runnable.WorkspaceConfigurationDependencies...),
 		Execution: map[string]any{
-			"timeout":          runnable.Execution.Timeout,
-			"cancellation":     string(runnable.Execution.Cancellation),
-			"recovery":         string(runnable.Execution.Recovery),
+			"timeout":      runnable.Execution.Timeout,
+			"cancellation": string(runnable.Execution.Cancellation),
+			"recovery":     string(runnable.Execution.Recovery),
+			// How the answer arrives is part of what an invocation is bound to:
+			// two packages differing only in it are called the same way and
+			// answered differently, so a digest that ignored it would call them
+			// the same package.
+			"completion":       string(runnable.Execution.GetCompletion()),
 			"concurrency":      runnable.Execution.Concurrency,
 			"max-input-bytes":  runnable.Execution.MaxInputBytes(),
 			"max-output-bytes": runnable.Execution.MaxOutputBytes(),

pkg/pack/pack_test.go

@@ -99,6 +99,12 @@ func TestTheConfigurationDigestFollowsWhatAnInvocationIsBoundTo(t *testing.T) {
 	if relaxed := digestFor(t, strings.Replace(declaration, "timeout: 30s", "timeout: 5m", 1)); relaxed == base {
 		t.Error("a different execution bound did not move the configuration digest")
 	}
+	// Two packages differing only in how their answer arrives are called the
+	// same way and answered differently, so the mode has to reach the digest.
+	if submitted := digestFor(t, strings.Replace(declaration,
+		"recovery: receipt", "recovery: receipt\n  completion: submit", 1)); submitted == base {
+		t.Error("declaring another completion mode did not move the configuration digest")
+	}
 }
 
 func TestTheSamePreparedTreeAlwaysPackagesToTheSameDigest(t *testing.T) {