diff --git a/src/document.ts b/src/document.ts
index e1dd8c402..e1d9cba5e 100644
--- a/src/document.ts
+++ b/src/document.ts
@@ -17,10 +17,13 @@ export interface IDocument<D = unknown> {
   data: D;
 }
 
-const normalizeSource = (source: Optional<string>): string | null => {
+export function normalizeSource(source: undefined): null;
+export function normalizeSource(source: string): string;
+export function normalizeSource(source: Optional<string>): string | null;
+export function normalizeSource(source: Optional<string>): string | null {
   if (source === void 0) return null;
-  return source && !startsWithProtocol(source) ? normalize(source) : source;
-};
+  return source.length > 0 && !startsWithProtocol(source) ? normalize(source) : source;
+}
 
 export class Document<D = unknown, R extends IParserResult = IParserResult<D>> implements IDocument<D> {
   protected readonly parserResult: R;
diff --git a/src/spectral.ts b/src/spectral.ts
index b7a96af47..3375c9e6d 100644
--- a/src/spectral.ts
+++ b/src/spectral.ts
@@ -5,7 +5,7 @@ import { YamlParserResult } from '@stoplight/yaml';
 import { memoize, merge } from 'lodash';
 
 import { STATIC_ASSETS } from './assets';
-import { Document, IDocument, IParsedResult, isParsedResult, ParsedDocument } from './document';
+import { Document, IDocument, IParsedResult, isParsedResult, ParsedDocument, normalizeSource } from './document';
 import { DocumentInventory } from './documentInventory';
 import { CoreFunctions, functions as coreFunctions } from './functions';
 import * as Parsers from './parsers';
@@ -80,7 +80,7 @@ export class Spectral {
     const document = this.parseDocument(target);
 
     if (document.source === null && opts.resolve?.documentUri !== void 0) {
-      (document as Omit<Document, 'source'> & { source: string }).source = opts.resolve?.documentUri;
+      (document as Omit<Document, 'source'> & { source: string }).source = normalizeSource(opts.resolve.documentUri);
     }
 
     const inventory = new DocumentInventory(document, this._resolver);