Fix readdir() returns unsorted entries related issues

Author: lahmatiy

CHANGELOG.md

@@ -1,3 +1,9 @@
+## next
+
+- Fixed methods for reading loose objects (`readObjectHeaderByOid`, `readObjectHeaderByHash`, `readObjectByOid`
+  and `readObjectByHash`) that were not working in some cases due to incorrect formation of the fanout table when `fs.readdir()` returns an unsorted list of entries
+- Fixed `listRemotes()` method to always return a sorted list of remotes
+
 ## 0.1.0 (2022-09-12)
 
 - Initial release

src/loose-object-index.ts

@@ -30,13 +30,12 @@ async function createLooseObjectMap(gitdir: string): Promise<LooseObjectMap> {
         )
     );
 
-    return new Map(objectDirs.flat());
+    return new Map(objectDirs.flat().sort(([a], [b]) => (a < b ? -1 : 1)));
 }
 
-function indexObjectNames(names: string[]) {
+function indexObjectNames(sortedNames: string[]) {
     const fanoutTable = new Array<[start: number, end: number]>(256);
-    const sortedNames = [...names].sort(([a], [b]) => (a < b ? -1 : 1));
-    const binaryNames = Buffer.from(names.join(''), 'hex');
+    const binaryNames = Buffer.from(sortedNames.join(''), 'hex');
 
     for (let i = 0, offset = 0; i < 256; i++) {
         const prevOffset = offset;

src/resolve-ref.ts

@@ -256,7 +256,7 @@ async function readRemotes(gitdir: string) {
         }
     }
 
-    return remotes;
+    return remotes.sort();
 }
 
 async function readLooseRefs(gitdir: string, remotes: string[]) {

test/helpers/fixture.ts

@@ -9,11 +9,23 @@ export const fixtures = Object.create(null);
 
 for (const name of fixtureNames) {
     fixtures[name] = {
-        repo: (options?: GitReaderOptions) =>
-            createGitReader(
-                fileURLToPath(new URL(fixturesPath + name + '/_git', import.meta.url)),
-                options
-            ),
+        repo: (options?: GitReaderOptions) => {
+            const origReaddir = fs.promises.readdir;
+
+            try {
+                // Patch readdir method to catch issues when readdir returns unsorted entries
+                // @ts-expect-error ts(2322)
+                fs.promises.readdir = (...args: Parameters<typeof fs.promises.readdir>) =>
+                    origReaddir(...args).then((list) => list.reverse());
+
+                return createGitReader(
+                    fileURLToPath(new URL(fixturesPath + name + '/_git', import.meta.url)),
+                    options
+                );
+            } finally {
+                fs.promises.readdir = origReaddir;
+            }
+        },
         data: JSON.parse(
             fs.readFileSync(
                 fileURLToPath(new URL(fixturesPath + name + '/data.json', import.meta.url)),