feat: allow autodiscover workspace override

[kshcherban]

what

• Add optional workspace field to the autodiscover config (both repo-level atlantis.yaml and server-side repos.yaml)
• When set, all autodiscovered projects use the configured workspace instead of detecting it from terraform { cloud { workspaces { name = "..." } } } blocks or falling back to "default"
• Fix a pre-existing bug where repo-level ignore_paths in the autodiscover section was silently ignored — the default global config always set a non-nil AutoDiscover{Mode: "auto", IgnorePaths: nil}, which caused isAutoDiscoverPathIgnored to short-circuit on the global config's nil IgnorePaths and never reach the
  repo-level config

why

• Users running separate Atlantis instances per workspace (e.g. one for qa, one for prod) on a shared repo need autodiscovery with both ignore_paths and a non-default workspace — these two features did not compose together
• The only existing alternative was defining explicit projects with dir globs, but ignore_paths does not apply to explicitly configured projects, leaving no way to exclude directories
• The ignore_paths bug meant that even the documented autodiscover.ignore_paths in atlantis.yaml had no effect unless the server-side config explicitly set ignore_paths — this fix changes the nil-check so that global IgnorePaths only takes precedence when explicitly configured (non-nil)

tests

• Added unit tests for workspace field round-trip through raw.AutoDiscover.ToValid() and YAML unmarshalling (server/core/config/raw/autodiscover_test.go)
• Added integration test "autodiscover workspace set in autodiscover config" in server/events/project_command_builder_test.go — verifies that workspace: qa + ignore_paths produces autodiscovered projects with workspace qa and excluded paths filtered out
• All existing tests pass (go test ./server/core/config/... ./server/events/...)

references

• Closes: ignore_path is not behaving correctly #6375
• Related: Add include option for autodiscover #5324 (feature request for include_paths)
• Related: autodiscover.ignore_paths not respected during apply #6325 (ignore_paths not respected during atlantis apply)

[Copilot]

Pull request overview

This PR adds an optional workspace field to the autodiscover configuration (both repo-level atlantis.yaml and server-side repos.yaml) that allows users to specify a non-default Terraform workspace for all autodiscovered projects. This enables scenarios where separate Atlantis instances per workspace operate on a shared repository. The PR also fixes a pre-existing bug where repo-level ignore_paths in the autodiscover section was silently ignored.

Changes:

• Added Workspace field to autodiscover config with precedence: global config > repo-level config
• Fixed bug where repo-level ignore_paths was bypassed when global config's IgnorePaths was nil
• Added comprehensive unit tests for workspace field and integration test demonstrating workspace + ignore_paths composition
• Updated documentation for both server-side and repo-level configurations

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
server/events/project_command_builder.go	Added workspace determination logic with proper precedence, fixed ignore_paths check to fall through to repo-level config
server/events/project_command_builder_test.go	Added integration test verifying workspace and ignore_paths work together
server/core/config/valid/autodiscover.go	Added Workspace field to the valid AutoDiscover struct
server/core/config/raw/autodiscover.go	Added Workspace field with YAML unmarshalling and passed through in ToValid()
server/core/config/raw/autodiscover_test.go	Added unit tests for Workspace field round-trip through YAML and ToValid()
runatlantis.io/docs/server-side-repo-config.md	Added documentation for workspace field
runatlantis.io/docs/repo-level-atlantis-yaml.md	Added documentation with examples showing workspace field