feat: automatically find existing IdentityFile

[FanBB2333]

Find existing keys in the default SSH config path and it can save some time if one doesn't have id_rsa key

[haginara]

LGTM

[Copilot]

Pull request overview

This PR adds automatic discovery of existing SSH identity files instead of always defaulting to ~/.ssh/id_rsa. This enhancement helps users who have different key types (like ed25519, ecdsa, etc.) by automatically detecting and suggesting the appropriate key file.

Key changes:

• Added get_identity_files() function to scan the .ssh directory for identity files matching the id_* naming pattern
• Modified the add command to use the discovered identity file as the default value instead of hardcoded id_rsa

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[Copilot]

The function does not handle potential permission errors when accessing the .ssh directory. If the user lacks read permissions for the directory, os.listdir() will raise a PermissionError. Consider adding error handling to gracefully fall back to the default identity file in such cases.

Suggested change

	for file in os.listdir(fullpath):
	# if not ends with .pub and starts with id_
	if file.startswith("id_") and not file.endswith(".pub") and os.path.isfile(os.path.join(fullpath, file)):
	keys.append(os.path.join(path, file))
	try:
	for file in os.listdir(fullpath):
	# if not ends with .pub and starts with id_
	if file.startswith("id_") and not file.endswith(".pub") and os.path.isfile(os.path.join(fullpath, file)):
	keys.append(os.path.join(path, file))
	except (PermissionError, FileNotFoundError):
	# Cannot access the directory or it does not exist; fall back to default key
	click.echo(f"[Warning] unable to access {fullpath}, using default identity file")
	return os.path.join(path, "id_rsa")

[Copilot]

The new get_identity_files() function is called during the add command flow, but there are no tests covering this new behavior. Since the repository has comprehensive test coverage for CLI commands (as seen in test_cli.py), tests should be added to verify the identity file discovery functionality, including edge cases like missing .ssh directory, multiple identity files, and no identity files found.

[Copilot]

The function uses click.echo for the warning on line 80 but uses print for the warning on line 85. This is inconsistent. Since this is a Click-based CLI application, click.echo should be used consistently for all output.

Suggested change

	print(f"[Warning] multiple identity files found: {keys}")
	click.echo(f"[Warning] multiple identity files found: {keys}")

[Copilot]

The function does not handle the case where the .ssh directory does not exist. This will cause an unhandled FileNotFoundError when os.listdir(fullpath) is called. Consider wrapping the directory listing in a try-except block or checking if the directory exists before attempting to list its contents.

[Copilot]

There's an inconsistency in path handling. On line 72, fullpath is created using os.path.expanduser(path), but on line 77, keys are appended using the unexpanded path variable instead of fullpath. This means that if the function is called with the default "/.ssh", the returned paths will contain the literal "" instead of the expanded home directory path. Either use fullpath throughout, or ensure the returned paths use the same format as the input.

Suggested change

	keys.append(os.path.join(path, file))
	if len(keys) == 0:
	# keys not found, return default key
	click.echo(f"[Warning] identity file not found, using default")
	return os.path.join(path, "id_rsa")
	keys.append(os.path.join(fullpath, file))
	if len(keys) == 0:
	# keys not found, return default key
	click.echo(f"[Warning] identity file not found, using default")
	return os.path.join(fullpath, "id_rsa")