fix: Remove URL encoding from base64 strings before decoding

src/storage/keyvalue/EncodingPathStorage.ts

@@ -62,7 +62,15 @@ export class EncodingPathStorage<T> implements KeyValueStorage<string, T> {
    * Converts an internal storage path string into the original path key.
    */
   protected pathToKey(path: string): string {
-    const buffer = Buffer.from(path.slice(this.basePath.length), 'base64');
+    // While the main part of a base64 encoded string is same from any changes from encoding or decoding URL parts,
+    // the `=` symbol that is used for padding is not.
+    // This can cause incorrect results when calling these function,
+    // where the original path contains `YXBwbGU%3D` instead of `YXBwbGU=`.
+    // This does not create any issues when the source store does not encode the string, so is safe to always call.
+    // For consistency, we might want to also always encode when creating the path in `keyToPath()`,
+    // but that would potentially break existing implementations that do not do encoding,
+    // and is not really necessary to solve any issues.
+    const buffer = Buffer.from(decodeURIComponent(path.slice(this.basePath.length)), 'base64');
     return buffer.toString('utf-8');
   }
 }

test/unit/storage/keyvalue/EncodingPathStorage.test.ts

@@ -48,4 +48,20 @@ describe('An EncodingPathStorage', (): void => {
     expect(results).toHaveLength(1);
     expect(results[0]).toEqual([ 'key', data ]);
   });
+
+  it('correctly handles keys that have been encoded by the source storage.', async(): Promise<void> => {
+    // Base 64 encoding of 'apple'
+    const encodedKey = 'YXBwbGU=';
+    const generatedPath = `${relativePath}${encodeURIComponent(encodedKey)}`;
+    const data = 'data';
+
+    map.set(generatedPath, data);
+
+    const results = [];
+    for await (const entry of storage.entries()) {
+      results.push(entry);
+    }
+    expect(results).toHaveLength(1);
+    expect(results[0]).toEqual([ 'apple', data ]);
+  });
 });