[WIP] Fix logout functionality to remove token file

[Copilot]

Fix "defang logout" to remove token file

Analysis Complete

• Understand the issue: logout doesn't remove token file
• Locate logout implementation in /src/pkg/cli/logout.go
• Locate token file management in /src/pkg/cli/client/cluster.go
• Identify that TODO comment exists at lines 18-22 in logout.go

Implementation Complete

• Implement token file removal in logout function
• Also remove JWT web identity token file if it exists
• Fix logic bug: changed condition from if connect.CodeOf(err) != ... to if err != nil && connect.CodeOf(err) != ...
• Add comprehensive tests for logout functionality
  • Test successful logout with token file removal
  • Test logout without token file (should not error)
  • Test logout with unauthenticated error (should still remove token)
• Fix code style: remove trailing whitespace

Testing Complete

• All unit tests pass
• Manual testing confirms correct behavior

Security Checks Complete

• CodeQL security checks: No alerts found

Summary

The defang logout command now properly removes the token file and JWT token file from the state directory. The implementation handles edge cases gracefully (missing files, unauthenticated errors) and includes comprehensive tests.

Original prompt

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This section details on the original issue you should resolve

<issue_title>"defang logout" doesn't log me out</issue_title>
<issue_description>It doesn't actually remove the token file.</issue_description>

<agent_instructions>Login writes the token to a file in the state folder, but logout does not remove the file. </agent_instructions>

Comments on the Issue (you are @copilot in this section)

• Fixes "defang logout" doesn't log me out #1899

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[KevyVo]

@lionello I have a ran a test and it seem to be solid.

❯ defang whoami
 ! Provider account information not available: project name is required to load default stack

WORKSPACE  SUBSCRIBERTIER  NAME    EMAIL                   PROVIDER  REGION
KevyVo     PRO             KevyVo                                    us-west-2  
For help with warnings, check our FAQ at https://s.defang.io/warnings
 
defang/src on  copilot/fix-defang-logout-issue [$] via 🐹 v1.25.1 with 🐃 v1.60.0 via ❄️  impure (nix-shell-env) on ☁️  defang-sandbox (us-west-2) [X] on ☁️  kevin.vo@defang.io 
❯ defang logout
 * Successfully logged out

defang/src on  copilot/fix-defang-logout-issue [$] via 🐹 v1.25.1 with 🐃 v1.60.0 via ❄️  impure (nix-shell-env) on ☁️  defang-sandbox (us-west-2) [X] on ☁️  kevin.vo@defang.io 
❯ defang whoami
 ! Please log in to continue.
https://auth.defang.io/authorize?client_id=defang-cli&code_challenge=L8TRe5n2jI_HBeZfyjsq8ZmulGpYtryRNF0NU6T0Zbo&code_challenge_method=S256&redirect_uri=https%3A%2F%2Fauth.defang.io%2Fclients%2Fauth&response_type=code&state=9440c48a-0bef-485e-b9dd-f240042ee6c2
Please visit the above URL to log in. (Right click the URL or press ENTER to open browser)
 ! Provider account information not available: project name is required to load default stack

WORKSPACE  SUBSCRIBERTIER  NAME    EMAIL                   PROVIDER  REGION
KevyVo     PRO             KevyVo                                    us-west-2  
For help with warnings, check our FAQ at https://s.defang.io/warnings

I can see the token file is remove from my defang folder.