pass: return correct error, and ignore empty stores on list

[thaJeztah]

commit 2fc2313 changed the errors returned by the pass credentials-helper to use a errCredentialsNotFound. This error string is used in the client to distinguish a "not found" error from other errors. (see client.Get).

However, there were additional second code-paths that returned a custom error, which would not be detected as a "not found" error, resulting in an error when logging out;

Removing login credentials for https://index.docker.io/v1/
WARNING: could not erase credentials:
https://index.docker.io/v1/: error erasing credentials - err: exit status 1, out: `error getting credentials - err: exit status 1, out: `no usernames for https://index.docker.io/v1/``

This patch:

• updates Pass.Get() to return a errCredentialsNotFound if no credentials were found
• updates Pass.List() to not return an error if any of the domains had no credentials stored.

- Description for the changelog

Fix "could not erase credentials" when trying to log out and no credentials were present

- A picture of a cute animal (not mandatory but encouraged)

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 51.46%. Comparing base (73b9e5d) to head (1bb9aa3).

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #321      +/-   ##
==========================================
- Coverage   54.10%   51.46%   -2.65%     
==========================================
  Files           9        8       -1     
  Lines         621      513     -108     
==========================================
- Hits          336      264      -72     
+ Misses        238      212      -26     
+ Partials       47       37      -10     

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[thaJeztah]

FWIW, we should probably consider using the PASSWORD_STORE_DIR env-var in tests (use t.TempDir() to create a temporary location and use that as PASSWORD_STORE_DIR (t.SetEnv()). That would prevent tests from interfering with other tests (or with an "actual" store on the user's machine)

But this also requires the pass-store to be initialised in that directory, so that required more work;

docker-credential-helpers/pass/pass.go

Lines 107 to 110 in 73b9e5d

	func getPassDir() string {
	if passDir := os.Getenv("PASSWORD_STORE_DIR"); passDir != "" {
	return passDir
	}

[krissetto]

LGTM

[nicks]

LGTM! thanks from all linux users 🐧 !

[thaJeztah]

Let me bring this one in; thanks!

I saw some small bits that could use a cleanup after this; will also discuss doing a new patch release 👍