bin scripts: Use the NoReturn type hint

The NoReturn type hint should be used to ensure the return type of
methods calling no-return methods are not falsely enforced to an
Optional return type.

Add the NoReturn type hint as needed and clear up existing Optional
returns together with any corresponding casts affected by the
above.

While there, also fix formatting.

1 files changed, 4 insertions, 4 deletions

diff --git a/bin/parallel-bootstrap-traverser.py b/bin/parallel-bootstrap-traverser.py
index ee5bb194..f27525d7 100755
--- a/bin/parallel-bootstrap-traverser.py
+++ b/bin/parallel-bootstrap-traverser.py
@@ -23,7 +23,7 @@ import sys
 import threading
 from enum import Enum
 from argparse import ArgumentParser
-from typing import Any, Callable, Dict, List, Optional, Tuple, cast
+from typing import Any, Callable, Dict, List, NoReturn, Optional, Tuple, cast
 
 # generic JSON type that avoids getter issues; proper use is being enforced by
 # return types of methods and typing vars holding return values of json getters
@@ -195,11 +195,11 @@ class AtomicListMap:
 g_CALLBACKS_PER_ID = AtomicListMap()
 
 
-def log(*args: str, **kwargs: Any):
+def log(*args: str, **kwargs: Any) -> None:
     print(*args, file=sys.stderr, **kwargs)
 
 
-def fail(s: str):
+def fail(s: str) -> NoReturn:
     log(s)
     sys.exit(1)
 
@@ -236,7 +236,7 @@ def link(src: str, dest: str) -> None:
         os.symlink(src, dest)
 
 
-def build_local(desc: Json, *, root: str, config: Json) -> Optional[str]:
+def build_local(desc: Json, *, root: str, config: Json) -> str:
     repo_name: str = desc["data"]["repository"]
     repo: List[str] = config["repositories"][repo_name]["workspace_root"]
     rel_path: str = desc["data"]["path"]