Gate runner dispatches on cancellation

internal/framework/pipeline/runner.go

@@ -81,6 +81,9 @@ func (r *Runner) Run(ctx context.Context, input RunInput) (output RunOutput, err
 	if r == nil {
 		return output, fmt.Errorf("runner must not be nil")
 	}
+	if err := ctx.Err(); err != nil {
+		return output, err
+	}
 	if err := validateRunInput(input); err != nil {
 		return output, err
 	}
@@ -165,6 +168,10 @@ func (r *Runner) Run(ctx context.Context, input RunInput) (output RunOutput, err
 		if metadataErr != nil {
 			return failOutput(output), fmt.Errorf("clone input adapter metadata: %w", metadataErr)
 		}
+		if err := ctx.Err(); err != nil {
+			_ = checkpoints.SourceFailed(adapter.Key(), err)
+			return failOutput(output), err
+		}
 		doc, err = adapter.Parse(ctx, contracts.ParseRequest{
 			SourceID:   input.SourceID,
 			Path:       input.Path,
@@ -172,6 +179,10 @@ func (r *Runner) Run(ctx context.Context, input RunInput) (output RunOutput, err
 			LLMProfile: input.pipeline.Input.LLMProfile,
 			Metadata:   requestMetadata,
 		})
+		if ctxErr := ctx.Err(); ctxErr != nil {
+			_ = checkpoints.SourceFailed(adapter.Key(), ctxErr)
+			return failOutput(output), ctxErr
+		}
 		if err != nil {
 			_ = checkpoints.SourceFailed(adapter.Key(), err)
 			return failOutput(output), fmt.Errorf("parse input with adapter %q: %w", adapter.Key(), err)
@@ -281,6 +292,9 @@ func (r *Runner) Run(ctx context.Context, input RunInput) (output RunOutput, err
 			return failOutput(output), err
 		}
 	}
+	if err := ctx.Err(); err != nil {
+		return failOutput(output), err
+	}
 
 	if len(output.Rejected) > 0 {
 		output.Manifest.ValidationStatus = "rejected"
@@ -294,11 +308,17 @@ func (r *Runner) Run(ctx context.Context, input RunInput) (output RunOutput, err
 	if err := attachModuleManifestMetadata(&output, "output", encoder); err != nil {
 		return failOutput(output), err
 	}
+	if err := ctx.Err(); err != nil {
+		return failOutput(output), err
+	}
 	outputStarted := time.Now().UTC()
 	evidenceArtifact, evidenceSummary, err := buildOutputEvidenceContext(input.Prepared, doc, output.NormalizeOutputs)
 	if err != nil {
 		return failOutput(output), err
 	}
+	if err := ctx.Err(); err != nil {
+		return failOutput(output), err
+	}
 	if evidenceSummary != nil {
 		if err := writeDebugTimed(debugRecorder, "output/evidence-context.json", debugTimedEnvelope{
 			Stage:     string(StageOutput),
@@ -308,6 +328,9 @@ func (r *Runner) Run(ctx context.Context, input RunInput) (output RunOutput, err
 		}); err != nil {
 			return failOutput(output), fmt.Errorf("write evidence context debug artifact: %w", err)
 		}
+		if err := ctx.Err(); err != nil {
+			return failOutput(output), err
+		}
 	}
 	outputDebugPayload := map[string]any{
 		"manifest":          output.Manifest,
@@ -328,10 +351,16 @@ func (r *Runner) Run(ctx context.Context, input RunInput) (output RunOutput, err
 	}); err != nil {
 		return failOutput(output), fmt.Errorf("write output debug artifact: %w", err)
 	}
+	if err := ctx.Err(); err != nil {
+		return failOutput(output), err
+	}
 	outputMetadata, err := cloneMetadata(input.Metadata)
 	if err != nil {
 		return failOutput(output), fmt.Errorf("clone output encoder metadata: %w", err)
 	}
+	if err := ctx.Err(); err != nil {
+		return failOutput(output), err
+	}
 	encoded, err := encoder.Encode(ctx, contracts.OutputRequest{
 		Manifest:         output.Manifest,
 		NormalizeOutputs: cloneSerializedOutputs(output.NormalizeOutputs),
@@ -342,7 +371,9 @@ func (r *Runner) Run(ctx context.Context, input RunInput) (output RunOutput, err
 		ChunkMap:         contracts.CloneSerializedArtifactPointer(acceptedChunkMap),
 		EvidenceContext:  contracts.CloneSerializedArtifactPointer(evidenceArtifact),
 	})
-	output.Warnings = append(output.Warnings, encoded.Warnings...)
+	if ctxErr := ctx.Err(); ctxErr != nil {
+		return failOutput(output), ctxErr
+	}
 	if err != nil {
 		return failOutput(output), fmt.Errorf("encode output with encoder %q: %w", encoder.Key(), err)
 	}
@@ -350,7 +381,6 @@ func (r *Runner) Run(ctx context.Context, input RunInput) (output RunOutput, err
 	if err != nil {
 		return failOutput(output), fmt.Errorf("validate output files from encoder %q: %w", encoder.Key(), err)
 	}
-	output.OutputFiles = files
 	if err := writeDebugTimed(debugRecorder, "output/output.json", debugTimedEnvelope{
 		Stage:     string(StageOutput),
 		ModuleKey: encoder.Key(),
@@ -362,6 +392,11 @@ func (r *Runner) Run(ctx context.Context, input RunInput) (output RunOutput, err
 	}); err != nil {
 		return failOutput(output), fmt.Errorf("write output debug artifact: %w", err)
 	}
+	if err := ctx.Err(); err != nil {
+		return failOutput(output), err
+	}
+	output.Warnings = append(output.Warnings, encoded.Warnings...)
+	output.OutputFiles = files
 
 	return output, nil
 }

internal/framework/pipeline/runner_concurrency_test.go

@@ -119,6 +119,96 @@ func (a *countingInputAdapter) Parse(ctx context.Context, request contracts.Pars
 	return a.InputAdapter.Parse(ctx, request)
 }
 
+type cancelingDebugRecorder struct {
+	cancel context.CancelFunc
+	onName string
+	once   sync.Once
+}
+
+func (r *cancelingDebugRecorder) Enabled() bool { return true }
+
+func (r *cancelingDebugRecorder) WriteJSON(name string, _ any) error {
+	if name == r.onName {
+		r.once.Do(r.cancel)
+	}
+	return nil
+}
+
+func (*cancelingDebugRecorder) WriteBytes(string, []byte) error { return nil }
+
+type cancelingOutputEncoder struct {
+	contracts.OutputEncoder
+	cancel context.CancelFunc
+	calls  atomic.Int32
+}
+
+func (e *cancelingOutputEncoder) Encode(context.Context, contracts.OutputRequest) (contracts.OutputResult, error) {
+	e.calls.Add(1)
+	e.cancel()
+	return contracts.OutputResult{
+		Files:    []contracts.OutputFile{{Name: "result.txt", ContentType: "text/plain", Bytes: []byte("result")}},
+		Warnings: []contracts.Warning{{ReasonCode: "returned-after-cancel"}},
+	}, nil
+}
+
+func TestRunnerSkipsInputAdapterWhenContextIsAlreadyCanceled(t *testing.T) {
+	prepared := preparedConcurrentPipeline(t, 1)
+	adapter := &countingInputAdapter{InputAdapter: prepared.input}
+	prepared.input = adapter
+	ctx, cancel := context.WithCancel(context.Background())
+	cancel()
+
+	_, err := New().Run(ctx, RunInput{Prepared: prepared, RawInput: []byte("input")})
+	if !errors.Is(err, context.Canceled) {
+		t.Fatalf("Run() error = %v, want context.Canceled", err)
+	}
+	if got := adapter.calls.Load(); got != 0 {
+		t.Fatalf("input Parse calls = %d, want none", got)
+	}
+}
+
+func TestRunnerSkipsOutputEncodingAfterDebugCancellation(t *testing.T) {
+	prepared := preparedConcurrentPipeline(t, 1)
+	encoder := &countingOrderedOutput{}
+	prepared.output = encoder
+	ctx, cancel := context.WithCancel(context.Background())
+
+	_, err := New().Run(ctx, RunInput{
+		Prepared: prepared,
+		RawInput: []byte("input"),
+		Debug:    &cancelingDebugRecorder{cancel: cancel, onName: "output/input.json"},
+	})
+	if !errors.Is(err, context.Canceled) {
+		t.Fatalf("Run() error = %v, want context.Canceled", err)
+	}
+	if got := encoder.calls.Load(); got != 0 {
+		t.Fatalf("output Encode calls = %d, want none", got)
+	}
+}
+
+func TestRunnerDiscardsOutputReturnedAfterCancellation(t *testing.T) {
+	prepared := preparedConcurrentPipeline(t, 1)
+	ctx, cancel := context.WithCancel(context.Background())
+	encoder := &cancelingOutputEncoder{OutputEncoder: prepared.output, cancel: cancel}
+	prepared.output = encoder
+
+	output, err := New().Run(ctx, RunInput{Prepared: prepared, RawInput: []byte("input")})
+	if !errors.Is(err, context.Canceled) {
+		t.Fatalf("Run() error = %v, want context.Canceled", err)
+	}
+	if got := encoder.calls.Load(); got != 1 {
+		t.Fatalf("output Encode calls = %d, want one", got)
+	}
+	if len(output.OutputFiles) != 0 {
+		t.Fatalf("output files = %#v, want none", output.OutputFiles)
+	}
+	for _, warning := range output.Warnings {
+		if warning.ReasonCode == "returned-after-cancel" {
+			t.Fatalf("output warnings include encoder warning after cancellation")
+		}
+	}
+}
+
 func TestRunnerFailsGeneratedHandoffBeforeConsumerExtraction(t *testing.T) {
 	prepared := preparedConcurrentPipeline(t, 1)
 	input := &countingInputAdapter{InputAdapter: prepared.input}