Keep parsing past a ref that cannot be followed

internal/provider/libopenapi/converter.go

@@ -660,9 +660,11 @@ func (c *converter) rebuild(p *base.SchemaProxy, ptr string) *base.Schema {
 	lp := p.GoLow()
 	ctx, node, idx := lp.GetContext(), lp.GetValueNode(), lp.GetIndex()
 	if isRef, _, _ := utils.IsNodeRefValue(node); isRef {
-		// A spec with a $ref libopenapi cannot find has no model, so the target is there.
 		node, idx, _, ctx = lowmodel.LocateRefNodeWithContext(ctx, node, idx)
 	}
+	if node == nil {
+		return nil
+	}
 
 	kept := keywords{c: c, node: utils.NodeAlias(node), ptr: ptr}.buildable()
 	ls := &lowbase.Schema{}

internal/provider/libopenapi/provider.go

@@ -17,6 +17,8 @@ import (
 
 	"github.com/pb33f/libopenapi"
 	"github.com/pb33f/libopenapi/datamodel"
+	v3 "github.com/pb33f/libopenapi/datamodel/high/v3"
+	lowv3 "github.com/pb33f/libopenapi/datamodel/low/v3"
 
 	"github.com/mockzilla/mockzilla-codegen/internal/diag"
 	"github.com/mockzilla/mockzilla-codegen/internal/provider"
@@ -66,7 +68,8 @@ func (p *Provider) Parse(ctx context.Context, data []byte, opts provider.ParseOp
 		return nil, nil, err
 	}
 
-	d, err := libopenapi.NewDocumentWithConfiguration(data, p.config())
+	cfg := p.config()
+	d, err := libopenapi.NewDocumentWithConfiguration(data, cfg)
 	if err != nil {
 		return nil, nil, fmt.Errorf("%w: %s: %w", provider.ErrParse, syntaxAt(opts.File, data, err), err)
 	}
@@ -75,14 +78,11 @@ func (p *Provider) Parse(ctx context.Context, data []byte, opts provider.ParseOp
 		return nil, nil, fmt.Errorf("%w: %s", err, opts.File)
 	}
 
-	model, buildErr := d.BuildV3Model()
-	if model == nil {
-		return nil, nil, fmt.Errorf("%w: %s: %w", provider.ErrParse, opts.File, buildErr)
-	}
-
+	// BuildV3Model drops the whole model for one ref it cannot follow, like one inside an example value.
+	low, buildErr := lowv3.CreateDocumentFromConfig(d.GetSpecInfo(), cfg)
 	c := newConverter(version, opts)
-	c.buildIssues(buildErr, model.Index.GetCircularReferences())
-	doc = c.document(&model.Model)
+	c.buildIssues(buildErr, low.Index.GetCircularReferences())
+	doc = c.document(v3.NewDocument(low))
 	return doc, c.diags.List(), nil
 }
 

internal/provider/libopenapi/provider_test.go

@@ -83,11 +83,6 @@ func TestParseErrors(t *testing.T) {
 		},
 		{name: "Not an OpenAPI document", src: "a: b\n", wantErr: provider.ErrParse},
 		{name: "Swagger 2.0", src: "swagger: '2.0'\ninfo: {title: t, version: '1'}\npaths: {}\n", wantErr: provider.ErrUnsupportedVersion},
-		{
-			name:    "Ref to nothing",
-			src:     minimalSpec + "components:\n  schemas:\n    A: {$ref: '#/components/schemas/Missing'}\n",
-			wantErr: provider.ErrParse,
-		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
@@ -100,6 +95,67 @@ func TestParseErrors(t *testing.T) {
 	}
 }
 
+func TestParseUnresolvedRefs(t *testing.T) {
+	t.Parallel()
+
+	file := diag.Origin{File: "spec.yaml"}
+	tests := []struct {
+		name      string
+		src       string
+		wantDiags []diag.Diagnostic
+	}{
+		{
+			name: "Ref inside an example value",
+			src: "openapi: 3.1.0\ninfo: {title: t, version: '1'}\n" +
+				"paths:\n  /a:\n    get:\n      responses:\n        '200':\n          description: ok\n" +
+				"          content:\n            application/json:\n" +
+				"              examples:\n                many: {$ref: '#/components/examples/Many'}\n" +
+				"components:\n  examples:\n    One:\n      value: {id: 1}\n" +
+				"    Many:\n      value: {$ref: '#/components/examples/One/value'}\n",
+			wantDiags: []diag.Diagnostic{{
+				Severity: diag.Warning,
+				Code:     diag.CodeBuildIssue,
+				Origin:   file,
+				Message:  "cannot resolve reference `#/components/examples/One/value`, it's missing: $.components.examples['One'].value [18:15]",
+			}},
+		},
+		{
+			name: "Ref to nothing",
+			src:  minimalSpec + "components:\n  schemas:\n    A: {$ref: '#/components/schemas/Missing'}\n",
+			wantDiags: []diag.Diagnostic{
+				{
+					Severity: diag.Warning,
+					Code:     diag.CodeBuildIssue,
+					Origin:   file,
+					Message:  "cannot resolve reference `#/components/schemas/Missing`, it's missing: $.components.schemas['Missing'] [6:9]",
+				},
+				{
+					Severity: diag.Warning,
+					Code:     diag.CodeBuildIssue,
+					Origin:   file,
+					Message:  "component `#/components/schemas/Missing` does not exist in the specification",
+				},
+				{
+					Severity: diag.Error,
+					Code:     diag.CodeSchemaBuild,
+					Pointer:  "/components/schemas/Missing",
+					Origin:   diag.Origin{File: "spec.yaml", Line: 6, Col: 8},
+					Message:  "schema cannot be built: build schema failed: reference cannot be found: '#/components/schemas/Missing'",
+				},
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+
+			_, diags, err := New().Parse(context.Background(), []byte(tt.src), provider.ParseOptions{File: "spec.yaml"})
+			require.NoError(t, err)
+			assert.Equal(t, tt.wantDiags, diags)
+		})
+	}
+}
+
 func TestSyntaxAt(t *testing.T) {
 	t.Parallel()