cannot create task stub directory because {} is not a direct

Error message

cannot create task stub directory because {} is not a directory

What it means

When generating stubs into nested paths, mise walks each stub's parent directories via `path.ancestors()`. Every existing ancestor must be a real directory (or a regular file that mise already scheduled to migrate into a directory). If an ancestor exists as anything else, mise cannot create the stub there and bails with this message.

Source

Thrown at src/cli/generate/task_stubs.rs:560

                        "cannot write task stub because {} is not a generated task stub",
                        display_path(&stub.path)
                    );
                }
            }
            Ok(_) => bail!(
                "cannot write task stub because {} is not a regular file",
                display_path(&stub.path)
            ),
            Err(err) if matches!(err.kind(), ErrorKind::NotFound | ErrorKind::NotADirectory) => {}
            Err(err) => return Err(err.into()),
        }
        validate_launcher_path(stub, launchers)?;
        for parent in stub.path.ancestors().skip(1) {
            match fs::symlink_metadata(parent) {
                Ok(metadata)
                    if metadata.file_type().is_dir()
                        || migrations.contains(&StubMigration::File(parent.to_path_buf())) => {}
                Ok(_) => bail!(
                    "cannot create task stub directory because {} is not a directory",
                    display_path(parent)
                ),
                Err(err)
                    if matches!(err.kind(), ErrorKind::NotFound | ErrorKind::NotADirectory) => {}
                Err(err) => return Err(err.into()),
            }
            if parent == dir {
                break;
            }
        }
    }
    Ok(migrations.into_iter().collect())
}

/// Refuse to replace a launcher beside a stub that mise did not write.
///
/// The stub path is the user's choice, so `bin/<task>.cmd` is a name a project may already be

View on GitHub (pinned to afd2eddd3a)

Solutions

Rename or remove the conflicting file/symlink at the ancestor path so the directory can be created.
Choose a different stub output layout that doesn't collide with existing files.
Re-run `mise generate task-stubs` after clearing the conflict.

Example fix

// before: .mise/tasks/group is a file, stub wants .mise/tasks/group/build
mv .mise/tasks/group .mise/tasks/group.old
mkdir -p .mise/tasks/group
mv .mise/tasks/group.old .mise/tasks/group/build
mise generate task-stubs

Defensive patterns

Strategy: validation

Validate before calling

target = Path('.mise/tasks/group/build')
for parent in target.parents:
    if parent.exists() and not parent.is_dir():
        raise RuntimeError(f"{parent} blocks directory creation for {target}")

Type guard

def ancestors_allow_dir(p: Path) -> bool:
    return all(not a.exists() or a.is_dir() for a in p.parents)

Prevention

Avoid naming a flat task file the same as a would-be task group directory
Plan task layout (flat vs grouped) before generating stubs
Run `mise tasks ls` to see existing names before choosing grouped stub paths

When it happens

Trigger: Running `mise generate task-stubs` with a stub output like `a/b/task` where `a` exists as a regular file or symlink — so `a/b` cannot be created as a directory.

Common situations: A file occupies the path where a task subdirectory should be (e.g. an old flat task named `group` while generating `group/task`); a symlinked parent directory rejected by the earlier symlink check.

Related errors

AI-assisted analysis of jdx/mise@afd2eddd3a (2026-09-09). Data as JSON: /api/errors/0803c16ed3ad0323. Report an issue: GitHub.