Finalize structured diagnostic aggregation

internal/modules/generic/output/json/encoder.go

@@ -259,7 +259,7 @@ type rejectedFile struct {
 }
 
 type warningsFile struct {
-	Warnings []contracts.Warning `json:"warnings"`
+	Groups []contracts.DiagnosticGroup `json:"groups"`
 }
 
 func logicalFiles(req contracts.OutputRequest, options Options) ([]contracts.OutputFile, error) {
@@ -332,7 +332,7 @@ func logicalFiles(req contracts.OutputRequest, options Options) ([]contracts.Out
 	if err != nil {
 		return nil, err
 	}
-	warningsOutput, err := jsonFile("warnings.json", warningsFile{Warnings: cloneWarnings(req.Warnings)})
+	warningsOutput, err := jsonFile("warnings.json", warningsFile{Groups: warningGroups(req.Diagnostics)})
 	if err != nil {
 		return nil, err
 	}
@@ -487,11 +487,14 @@ func cloneRejected(rejected []contracts.RejectedOutput) []contracts.RejectedOutp
 	return append([]contracts.RejectedOutput(nil), rejected...)
 }
 
-func cloneWarnings(warnings []contracts.Warning) []contracts.Warning {
-	if len(warnings) == 0 {
-		return []contracts.Warning{}
+func warningGroups(collection contracts.DiagnosticCollection) []contracts.DiagnosticGroup {
+	groups := make([]contracts.DiagnosticGroup, 0)
+	for _, group := range collection.Groups {
+		if group.Disposition == contracts.DiagnosticDispositionWarning {
+			groups = append(groups, group)
+		}
 	}
-	return append([]contracts.Warning(nil), warnings...)
+	return contracts.CloneDiagnosticCollection(contracts.DiagnosticCollection{Groups: groups}).Groups
 }
 
 func encoderErrorf(format string, args ...any) error {

internal/modules/generic/output/json/encoder_test.go

@@ -146,7 +146,7 @@ func TestEncodeReturnsLogicalFilesForNormalizedOutputs(t *testing.T) {
 				ValidatorName: "validator",
 			},
 		},
-		Warnings: []contracts.Warning{{ReasonCode: "warning", Message: "check source"}},
+		Diagnostics: warningDiagnostics("warning", "check source"),
 	}
 
 	result, err := New().Encode(context.Background(), req)
@@ -211,7 +211,7 @@ func TestEncodeIncludesRejectedAndWarningsWhenEmpty(t *testing.T) {
 		t.Fatalf("rejected = %#v, want empty array", got)
 	}
 	warnings := decodeObject(t, fileBytes(t, result.Files, "warnings.json"))
-	if got := warnings["warnings"].([]any); len(got) != 0 {
+	if got := warnings["groups"].([]any); len(got) != 0 {
 		t.Fatalf("warnings = %#v, want empty array", got)
 	}
 }
@@ -665,7 +665,7 @@ func TestEncodeDoesNotMutateInputs(t *testing.T) {
 		Rejected: []contracts.RejectedOutput{
 			{Stage: "extract", LaneID: "spells", Message: "not accepted"},
 		},
-		Warnings: []contracts.Warning{{ReasonCode: "warning", Message: "message"}},
+		Diagnostics: warningDiagnostics("warning", "message"),
 	}
 	before := mustMarshal(t, req)
 
@@ -681,14 +681,14 @@ func TestEncodeDoesNotMutateInputs(t *testing.T) {
 	req.NormalizeOutputs[0].Artifact.Content[0] = '['
 	req.NormalizeOutputs[0].Artifact.Metadata["name"] = "changed"
 	req.Rejected[0].Message = "changed"
-	req.Warnings[0].Message = "changed"
+	req.Diagnostics.Groups[0].Samples[0].Message = "changed"
 
 	if !stdjson.Valid(fileBytes(t, result.Files, "lanes/spells.json")) {
 		t.Fatal("output changed after request mutation")
 	}
 	warnings := decodeObject(t, fileBytes(t, result.Files, "warnings.json"))
-	gotWarnings := warnings["warnings"].([]any)
-	if gotWarnings[0].(map[string]any)["message"] != "message" {
+	gotWarnings := warnings["groups"].([]any)
+	if gotWarnings[0].(map[string]any)["samples"].([]any)[0].(map[string]any)["message"] != "message" {
 		t.Fatalf("warnings output changed after request mutation: %#v", gotWarnings)
 	}
 }
@@ -696,9 +696,7 @@ func TestEncodeDoesNotMutateInputs(t *testing.T) {
 func TestOutputFilesDoNotContainWarnings(t *testing.T) {
 	result, err := New().Encode(context.Background(), contracts.OutputRequest{
 		NormalizeOutputs: []contracts.SerializedOutput{normalizeOutput("spells", `{"spell":"Shield"}`)},
-		Warnings: []contracts.Warning{
-			{ReasonCode: "pipeline-warning", Message: "warning"},
-		},
+		Diagnostics:      warningDiagnostics("pipeline-warning", "warning"),
 	})
 	if err != nil {
 		t.Fatalf("Encode() error = %v, want nil", err)
@@ -710,6 +708,17 @@ func TestOutputFilesDoNotContainWarnings(t *testing.T) {
 	}
 }
 
+func warningDiagnostics(reasonCode, message string) contracts.DiagnosticCollection {
+	return contracts.DiagnosticCollection{Groups: []contracts.DiagnosticGroup{{
+		Disposition:     contracts.DiagnosticDispositionWarning,
+		Category:        contracts.DiagnosticCategoryDegradation,
+		ReasonCode:      reasonCode,
+		Origin:          contracts.DiagnosticOrigin{Stage: contracts.DiagnosticOriginStageChunk},
+		OccurrenceCount: 1,
+		Samples:         []contracts.DiagnosticSample{{Scope: "test", Message: message}},
+	}}}
+}
+
 func normalizeOutput(laneID string, content string) contracts.SerializedOutput {
 	return contracts.SerializedOutput{
 		LaneID:        laneID,