fix: auto-discover workspaces when in subdirectories

[marcoceppi]

what

Detect workspaces from subdirectories during autodiscovery.

why

• When using terraform cloud configurations for multiple projects / modules in a single repo the default Atlantis workflow will fail

tests

• I have tested my changes by building a local version of Atlantis and deploying it against a repo that previously failed auto discovery
• I have created unit tests to verify this functionality continues to work going forward

references

closes #3252
supersedes #3253

[GenPage]

💯 Thanks Marco!

[X-Guardian]

These tests are flaky on Linux and fail consistently on Windows.

On Linux sometimes fails with:

--- FAIL: TestDefaultProjectCommandBuilder_BuildAutoplanCommands/workspaces_from_subdirectories_detected (0.01s)
        project_command_builder_test.go:292: [work != test]

            exp: work******
            got: test

On Windows, always fails with:

--- FAIL: TestDefaultProjectCommandBuilder_BuildAutoplanCommands/workspaces_from_subdirectories_detected (0.00s)
        project_command_builder_test.go:288: [2 != 1]

            exp: int(2)******
            got: int(1)

Can we revert the merge of this PR and have this looked at.

[GenPage]

I think I could see where this possibly flaky issue is coming from in the tests. Here's my running theory.

atlantis/server/events/project_command_builder_test.go

Lines 170 to 207 in 566b15f

	Description: "workspaces from subdirectories detected",
	TestDirStructure: map[string]interface{}{
	"work": map[string]interface{}{
	"main.tf": `
	terraform {
	cloud {
	organization = "atlantis-test"
	workspaces {
	name = "test-workspace1"
	}
	}
	}`,
	},
	"test": map[string]interface{}{
	"main.tf": `
	terraform {
	cloud {
	organization = "atlantis-test"
	workspaces {
	name = "test-workspace12"
	}
	}
	}`,
	},
	},
	exp: []expCtxFields{
	{
	ProjectName: "",
	RepoRelDir: "work",
	Workspace: "test-workspace1",
	},
	{
	ProjectName: "",
	RepoRelDir: "test",
	Workspace: "test-workspace12",
	},
	},
	},

For this specific test case, there is two test directories test and work, from which each have different workspaces.

atlantis/server/events/project_command_builder_test.go

Lines 280 to 294 in 566b15f

	ctxs, err := builder.BuildAutoplanCommands(&command.Context{
	PullRequestStatus: models.PullReqStatus{
	Mergeable: true,
	},
	Log: logger,
	Scope: scope,
	})
	Ok(t, err)
	Equals(t, len(c.exp), len(ctxs))
	for i, actCtx := range ctxs {
	expCtx := c.exp[i]
	Equals(t, expCtx.ProjectName, actCtx.ProjectName)
	Equals(t, expCtx.RepoRelDir, actCtx.RepoRelDir)
	Equals(t, expCtx.Workspace, actCtx.Workspace)
	}

Here is the logic to compare the actual contexts which the ones that are expected set in an array. The camparsion being done is the string key of the map interface for TestDirStructure compared to the RepoRelDir in the expCtxFields array.

I believe the flaky test is when the arrays get out of order compared to one another. So test != work happens