dagger/dagger · error

attach workspace git ref source: %w

Error message

attach workspace git ref source: %w

What it means

This error wraps a failure from the attach call while re-attaching a WorkspaceSourceGitRef's Ref result (core/workspace.go:933). When a workspace's source is a git ref, the stored GitRef result must be re-attached to the current query context; an attach failure is surfaced with this message.

Source

Thrown at core/workspace.go:933

			return nil, nil
		}
		attached, err := attach(src.Root)
		if err != nil {
			return nil, fmt.Errorf("attach workspace directory source: %w", err)
		}
		root, ok := attached.(dagql.ObjectResult[*Directory])
		if !ok {
			return nil, fmt.Errorf("attach workspace directory source: unexpected result %T", attached)
		}
		src.Root = root
		return []dagql.AnyResult{root}, nil
	case *WorkspaceSourceGitRef:
		if src.Ref.Self() == nil {
			return nil, nil
		}
		attached, err := attach(src.Ref)
		if err != nil {
			return nil, fmt.Errorf("attach workspace git ref source: %w", err)
		}
		switch ref := attached.(type) {
		case dagql.Result[*GitRef]:
			src.Ref = ref
			return []dagql.AnyResult{ref}, nil
		case dagql.ObjectResult[*GitRef]:
			src.Ref = ref.Result
			return []dagql.AnyResult{ref}, nil
		default:
			return nil, fmt.Errorf("attach workspace git ref source: unexpected result %T", attached)
		}
	case *WorkspaceSourceOverlay:
		var deps []dagql.AnyResult
		baseDeps, err := attachWorkspaceSource(attach, src.Base)
		if err != nil {
			return nil, err
		}
		deps = append(deps, baseDeps...)

View on GitHub (pinned to 82ba2681db)

Solutions

1. Inspect the wrapped inner error to find the attach failure root cause.
2. Re-create the workspace git source in the current session (re-run the git query).
3. Retry with a fresh client so the GitRef result attaches in-context.
4. Verify the git ref/repo is still reachable if the inner error points to git resolution.

Example fix

// before: stale git ref id
gitRef := GitRefFromID(savedID)
// after: resolve fresh in the current client
gitRef := client.Git("https://...").Ref("main")

// confirm the git ref is resolvable before building the workspace
ref, err := client.Git(repoURL).Ref(branch).ID(ctx)
if err != nil {
    return fmt.Errorf("git ref not resolvable in this session: %w", err)
}

func hasValidGitRef(src *core.WorkspaceSourceGitRef) bool {
    return src != nil && src.Ref.Self() != nil
}

ws, err := buildGitWorkspace(ctx, repo, branch)
if err != nil {
    if strings.Contains(err.Error(), "attach workspace git ref source") {
        // re-resolve the git ref freshly
        ws = client.Workspace(client.Git(repo).Ref(branch))
    }
    return err
}

When it happens

Trigger: Using a Workspace sourced from a git ref (WorkspaceSourceGitRef with non-nil Ref) where the attach call for src.Ref errors during dependency attachment — e.g. cached git ref result reused across query scopes.

Common situations: Replaying workspaces built from git sources in a new session; expired or evicted cached git ref results; engine restart between result creation and reuse.

Related errors

• attach workspace git workspace: %w
• read workspace root: %w
• failed to add vcs generated file: %w
• workspace directory %q: create rootless directory: %w
• seed overlay delta root: %w

AI-assisted analysis of dagger/dagger@82ba2681db (2026-09-05). Data as JSON: /api/errors/346b8248e98fcd3c. Report an issue: GitHub.