Review tab gets stuck on "Loading diff" on Windows because Codex App passes /F:/... as a literal path to git diff

What version of the Codex App are you using (From “About Codex” dialog)?

26.409.20454

What subscription do you have?

pro

What platform is your computer?

Microsoft Windows NT 10.0.26200.0 x64

What issue are you seeing?

In the Codex desktop app on Windows, the Review tab gets stuck on Loading diff for a normal text file and never renders the diff.

I reproduced this with a newly created dummy.txt containing a single line of plain text. The file appears in the changed files list and is clickable, but the diff pane stays on Loading diff forever.

This does not appear to be a Git or file-content problem. Git returns the expected diff immediately when run directly.

From the Codex desktop logs, the app appears to call Git with a literal path like /F:/HogeProject/Test/dummy.txt. That is important because this is not just a shell rendering issue. The logs show it in the argument list passed to Git.

That literal path appears to be invalid for git.exe on Windows and causes Git to fail with exit code 128, which appears to leave the Review pane stuck.

<img width="530" height="181" alt="Image" src="https://github.com/user-attachments/assets/85984d36-7940-47a6-92b9-c4f79f93bd81" />

What steps can reproduce the bug?

1. Open Codex App on Windows
2. Open a Git workspace
3. Create a new text file such as dummy.txt
4. Add one line of text
5. Stage the file
6. Open the Review tab
7. Click the file in the changed files list
8. Observe that the pane stays on Loading diff

I also tried:

• unstaging and restaging the file
• changing the integrated terminal shell to Git Bash
• restarting / reopening the app
• None of these fixed the issue.

What is the expected behavior?

The Review tab should render the text diff normally.

Additional information

Project root: F:/HogeProject/Test Git root: F:/HogeProject/Test

The file was a plain UTF-8 text file, not binary.

Example contents:
これは Review 表示確認用のダミーテキストです

Git sees the file as normal text.
Command: git check-attr --all -- dummy.txt
Output:

diff --git a/dummy.txt b/dummy.txt
new file mode 100644
index 0000000..xxxxxxxx
--- /dev/null
+++ b/dummy.txt
@@ -0,0 +1 @@
+これは Review 表示確認用のダミーテキストです

I also reproduced the suspected root cause directly outside the app.
This fails when Git is called directly from PowerShell:

Command: git diff --cached -- /F:/HogeProject/Test/dummy.txt
Error: fatal: Invalid path '/F:': No such file or directory

These succeed:

git diff --cached -- F:/HogeProject/Test/dummy.txt
git diff --cached -- dummy.txt

I also verified that using Git Bash does not fix the Codex App Review issue, which suggests the problem is in Codex App's internal Git invocation rather than the integrated terminal setting.

From the Codex desktop log, Review appears to repeatedly run a command equivalent to git diff --cached -- /F:/HogeProject/Test/dummy.txtand gets exitCode=128.

So this looks like a Windows path normalization bug in Codex App's diff/review flow. The key point is that /F:/... appears to be passed as a literal Git argument, and reproducing that exact argument outside the app fails, while the same command succeeds with F:/....