Supress tracebacks for "expected" exceptions in more places

afbee03f26 tried to suppress tracebacks, but I was testing it by calling
'PYTHONPATH=… python -m rust2rpm' and completely missed the fact that the
setuptools entrypoint wrapper calls main() directly and is not covered by
this.

Also, the same should be done for cargo-inspector.

rust2rpm/__main__.py

@@ -299,6 +299,20 @@ def detect_rpmautospec(default_target, spec_file):
     autochangelog_re = r"^\s*%(?:autochangelog|\{\??autochangelog\})\b"
     return any(re.match(autochangelog_re, line) for line in text.splitlines())
 
+
+@contextlib.contextmanager
+def exit_on_common_errors():
+    """Suppress tracebacks on common "expected" exceptions"""
+    try:
+        yield
+    except requests.exceptions.HTTPError as e:
+        sys.exit(f'Failed to download metadata: {e}')
+    except subprocess.CalledProcessError as e:
+        cmd = shlex.join(e.cmd)
+        sys.exit(f'Subcommand failed with code {e.returncode}: {cmd}')
+
+
+@exit_on_common_errors()
 def main():
     default_target = get_default_target()
 
@@ -473,11 +487,6 @@ def main():
             with open(patch_file, "w") as fobj:
                 fobj.writelines(diff)
 
+
 if __name__ == "__main__":
-    try:
+    main()
-        main()
-    except requests.exceptions.HTTPError as e:
-        sys.exit(f'Failed to download metadata: {e}')
-    except subprocess.CalledProcessError as e:
-        cmd = shlex.join(e.cmd)
-        sys.exit(f'Subcommand failed with code {e.returncode}: {cmd}')

rust2rpm/inspector.py

@@ -5,6 +5,7 @@ import sys
 
 from . import Metadata
 from .metadata import normalize_deps, Dependency
+from .__main__ import exit_on_common_errors
 
 
 def _get_binaries(cargo_toml):
@@ -49,6 +50,7 @@ def _cargo_toml(source_path, path, exclude_vendor=True):
     raise FileNotFoundError(f'Cargo.toml not found for binary {binary_or_cargo_toml}')
 
 
+@exit_on_common_errors()
 def main():
     parser = argparse.ArgumentParser()
     group = parser.add_mutually_exclusive_group(required=True)