From e2bd4a9000dce0768fd6298a5a3d250c88baca6e Mon Sep 17 00:00:00 2001
From: Pandelis Zembashis <p@ndel.is>
Date: Sat, 17 Oct 2026 21:32:43 -0700
Subject: [PATCH 1/2] Validate cached refs in one Git transaction

---
 __test__/composal-cache.test.ts | 6 ++++++
 dist/index.js                   | 2 +-
 package-lock.json               | 4 ++--
 package.json                    | 2 +-
 src/composal-cache.ts           | 2 +-
 5 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/__test__/composal-cache.test.ts b/__test__/composal-cache.test.ts
index 0236fd5..c782f8b 100644
--- a/__test__/composal-cache.test.ts
+++ b/__test__/composal-cache.test.ts
@@ -233,6 +233,12 @@ test('full history, annotated tags and sparse checkout keep standard Git behavio
   await expect(fs.access(path.join(workspace, 'root-file'))).rejects.toThrow()
 })
 
+test('bulk ref creation rejects invalid names without publishing local refs', async () => {
+  await expect(
+    cache({'refs/heads/main': second, 'refs/heads/invalid..name': first})
+  ).rejects.toThrow('Local checkout cache operation failed')
+})
+
 test('dissociate makes the checkout usable after the mounted cache disappears', async () => {
   const checkout = await cache()
   expect(
diff --git a/dist/index.js b/dist/index.js
index def80ec..a3ff300 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -42329,9 +42329,9 @@ class CheckoutCache {
         for (const [name, value] of Object.entries(refs)) {
             if (!oid.test(value) || !name.startsWith('refs/'))
                 throw new Error('Invalid checkout cache ref');
-            run(['check-ref-format', name], localOrigin);
             commands.push(`create ${name} ${value}`);
         }
+        // update-ref validates the complete batch, including every ref name.
         run(['update-ref', '--stdin'], localOrigin, commands.join('\n') + '\n');
         const alternateFile = external_node_path_namespaceObject.join(workspace, '.git', 'objects', 'info', 'alternates');
         let previous = '';
diff --git a/package-lock.json b/package-lock.json
index acd9175..f13d01f 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "composal-checkout",
-  "version": "1.0.0",
+  "version": "1.0.1",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "composal-checkout",
-      "version": "1.0.0",
+      "version": "1.0.1",
       "license": "MIT",
       "dependencies": {
         "@actions/core": "^3.0.1",
diff --git a/package.json b/package.json
index ec8de79..a2df9f2 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "composal-checkout",
-  "version": "1.0.0",
+  "version": "1.0.1",
   "description": "Composal Git checkout action",
   "type": "module",
   "main": "lib/main.js",
diff --git a/src/composal-cache.ts b/src/composal-cache.ts
index 12482d6..c558fbc 100644
--- a/src/composal-cache.ts
+++ b/src/composal-cache.ts
@@ -185,9 +185,9 @@ export class CheckoutCache {
     for (const [name, value] of Object.entries(refs)) {
       if (!oid.test(value) || !name.startsWith('refs/'))
         throw new Error('Invalid checkout cache ref')
-      run(['check-ref-format', name], localOrigin)
       commands.push(`create ${name} ${value}`)
     }
+    // update-ref validates the complete batch, including every ref name.
     run(['update-ref', '--stdin'], localOrigin, commands.join('\n') + '\n')
     const alternateFile = path.join(
       workspace,

From eda86db83397b7b8ba2d88fead63c9cd85e644a6 Mon Sep 17 00:00:00 2001
From: Pandelis Zembashis <p@ndel.is>
Date: Sat, 17 Oct 2026 21:33:34 -0700
Subject: [PATCH 2/2] Reject command delimiters before bulk ref validation

---
 __test__/composal-cache.test.ts | 2 +-
 dist/index.js                   | 4 +++-
 src/composal-cache.ts           | 6 +++++-
 3 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/__test__/composal-cache.test.ts b/__test__/composal-cache.test.ts
index c782f8b..5ed2080 100644
--- a/__test__/composal-cache.test.ts
+++ b/__test__/composal-cache.test.ts
@@ -277,7 +277,7 @@ test('cache fetch failure removes its alternate and allows normal GitHub fetchin
 
 test('malformed cached ref metadata cannot write outside the temporary ref database', async () => {
   await expect(
-    cache({'refs/heads/main\ncreate refs/heads/injected': second})
+    cache({[`refs/heads/main ${second}\ncreate refs/heads/injected`]: second})
   ).rejects.toThrow()
   await expect(
     fs.access(path.join(workspace, '.git', 'objects', 'info', 'alternates'))
diff --git a/dist/index.js b/dist/index.js
index a3ff300..e399124 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -42327,7 +42327,9 @@ class CheckoutCache {
         const refs = { ...manifest.refs, 'refs/composal/target': manifest.object_oid };
         const commands = [];
         for (const [name, value] of Object.entries(refs)) {
-            if (!oid.test(value) || !name.startsWith('refs/'))
+            if (!oid.test(value) ||
+                !name.startsWith('refs/') ||
+                /[\x00-\x20\x7f]/.test(name))
                 throw new Error('Invalid checkout cache ref');
             commands.push(`create ${name} ${value}`);
         }
diff --git a/src/composal-cache.ts b/src/composal-cache.ts
index c558fbc..e63522a 100644
--- a/src/composal-cache.ts
+++ b/src/composal-cache.ts
@@ -183,7 +183,11 @@ export class CheckoutCache {
     const refs = {...manifest.refs, 'refs/composal/target': manifest.object_oid}
     const commands: string[] = []
     for (const [name, value] of Object.entries(refs)) {
-      if (!oid.test(value) || !name.startsWith('refs/'))
+      if (
+        !oid.test(value) ||
+        !name.startsWith('refs/') ||
+        /[\x00-\x20\x7f]/.test(name)
+      )
         throw new Error('Invalid checkout cache ref')
       commands.push(`create ${name} ${value}`)
     }