credential-cache error "fatal: unable to connect to cache daemon: Unknown error"

[hickford]

• I was not able to find an open or closed issue matching what I'm seeing

Setup

• Which version of Git for Windows are you using? Is it 32-bit or 64-bit?

$ git --version --build-options
git version 2.47.1.windows.1
cpu: x86_64
built from commit: 2cd22437f64229935dc564db969cbcbfed5e9045
sizeof-long: 4
sizeof-size_t: 8
shell-path: D:/git-sdk-64-build-installers/usr/bin/sh
feature: fsmonitor--daemon
libcurl: 8.11.0
OpenSSL: OpenSSL 3.2.3 3 Sep 2024
zlib: 1.3.1

• Which version of Windows are you running?

Windows 11

$ cmd.exe /c ver
Microsoft Windows [Version 10.0.26100.2314]

Details

• Which terminal/shell are you running Git from?

cmd

• What commands did you run to trigger this issue?

printf "host=bitbucket.org\nprotocol=https\nusername=tim\npassword=hunter2\n" | git credential-cache store
printf "host=bitbucket.org\nprotocol=https\n" | git credential-cache get

• What did you expect to occur after running these commands?

Credential saved and retrieved.

• What actually happened instead?

Error "fatal: unable to connect to cache daemon: Unknown error"

[hickford]

On another computer this bug occurs intermittently.

[hickford]

Workaround: delete empty directory %USERPROFILE\.cache\git\credential

[hickford]

@rimrul Try this to reproduce (corrected path):

1. Exit cache git credential-cache exit
2. Store credential with 10 second timeout printf "host=example.com\nprotocol=https\nusername=tim\npassword=hunter2\n" | git credential-cache --timeout 10 store
3. Observe that file %USERPROFILE\.cache\git\credential\socket is created
4. Wait about 40 seconds
5. Observe that file %USERPROFILE\.cache\git\credential\socket has disappeared
6. Get credential printf "host=example.com\nprotocol=https\n" | git credential-cache get

Expected: empty output

What actually happens: "fatal: unable to connect to cache daemon: Unknown error". Interestingly echo %ERRORLEVEL% prints 128 (ENOTSOCK in errno.h).

To workaround: delete empty directory %USERPROFILE\.cache\git\credential

[rimrul]

That does reproduce for me, with a slight difference. The socket file appears and disappears in %USERPROFILE%\.cache\git\credential

[rimrul]

And the mistery errno is ECONNREFUSED.

[hickford]

@rimrul Unfortunately error message "unable to connect to cache daemon" has two possible sources:

git/builtin/credential-cache.c

Lines 108 to 114 in f1241af

	if (send_request(socket, &buf) < 0) {
	if (connection_fatally_broken(errno))
	die_errno("unable to connect to cache daemon");
	if (flags & FLAG_SPAWN) {
	spawn_daemon(socket);
	if (send_request(socket, &buf) < 0)
	die_errno("unable to connect to cache daemon");

Assuming the error comes from the first source, perhaps the fix is to add extra error codes to function connection_fatally_broken:

git/builtin/credential-cache.c

Lines 24 to 27 in f1241af

	static int connection_fatally_broken(int error)
	{
	return (error != ENOENT) && (error != ENETDOWN);
	}

[hickford]

And the mistery errno is ECONNREFUSED.

How did you determine that?

For me exit code %errorlevel% was 128. Is that equal to errno? I can't see how die_errno works.

[rimrul]

I wrote a small wrapper around strerror() that handled the cases that default strerror() didn't and then ran the reproducer.

[rimrul]

Looking over the code of die_errno() it looks like it usually ends up in die_builtin() which always exits 128.

git/usage.c

Lines 73 to 79 in f1241af

	static NORETURN void die_builtin(const char *err, va_list params)
	{
	report_fn die_message_fn = get_die_message_routine();
	die_message_fn(err, params);
	exit(128);
	}

[hickford]

Thanks! So it was just a coincidence that errno 128 happens to relates to sockets. I'll cancel my PR.