Should include filename in error displayed if plugin file in baseline not found

[msabramo]

• I'm submitting a ...

  • bug report
  • feature request

• What is the current behavior?
  If you run something like detect-secrets-hook --baseline .secrets.baseline setup.py and secrets.baseline references a custom plugin that doesn't exist, you get a FileNotFoundError with a long traceback, but unfortunately it doesn't tell you which file is missing.

• If the current behavior is a bug, please provide the steps to reproduce and if possible a minimal demo of the problem

$ cat .secrets.baseline
{
  "version": "1.4.0",
  "plugins_used": [
    {
      "name": "FakeCustomPlugin",
      "path": "file://./path/to/plugin/that/does/not/exist/plugin.py"
    }
  ],
  "filters_used": [],
  "results": {}
}

$ detect-secrets-hook --baseline .secrets.baseline setup.py
Traceback (most recent call last):
...
  File "/Users/abramowi/Code/OpenSource/detect-secrets/detect_secrets/util/importlib.py", line 88, in import_file_as_module
    raise FileNotFoundError
FileNotFoundError

Note that a FileNotFoundError is raised, but it doesn't say which file was not found.

• What is the expected behavior?

A user-friendly error message that tells the user which file was not found. For example, if an invalid plugin is passed in on the command-line:

$ detect-secrets-hook --plugin ./app/detect-secrets/plugins.py --baseline .secrets.baseline
...
detect-secrets-hook: error: argument -p/--plugin: ./app/detect-secrets/plugins.py is not a valid file.

So a better behavior for this case would be something like this:

$ detect-secrets-hook --baseline .secrets.baseline setup.py
detect-secrets-hook: error: plugin referenced in .secrets.baseline: ./path/to/plugin/that/does/not/exist/plugin.py is not a valid file.

But I'd be happy if it still displayed a traceback, but FileNotFoundError was raised with the filename that was not found as a parameter.

• What is the motivation / use case for changing the behavior?
  To make debugging easier. I spent a bunch of time yesterday troubleshooting an issue like this and this change would've saved me a lot of time.

• Please tell us about your environment:

  • detect-secrets Version: 1.4.0
  • Python Version: 3.10
  • OS Version: OS X 12.6.8
  • File type (if applicable):

• Other information

$ detect-secrets-hook --baseline .secrets.baseline setup.py
Traceback (most recent call last):
  File "/Users/abramowi/Code/OpenSource/detect-secrets/.venv/bin/detect-secrets-hook", line 8, in <module>
    sys.exit(main())
             ^^^^^^
  File "/Users/abramowi/Code/OpenSource/detect-secrets/detect_secrets/pre_commit_hook.py", line 30, in main
    secrets.scan_file(filename)
  File "/Users/abramowi/Code/OpenSource/detect-secrets/detect_secrets/core/secrets_collection.py", line 75, in scan_file
    for secret in scan.scan_file(os.path.join(self.root, filename)):
  File "/Users/abramowi/Code/OpenSource/detect-secrets/detect_secrets/core/scan.py", line 141, in scan_file
    if not get_plugins():   # pragma: no cover
           ^^^^^^^^^^^^^
  File "/Users/abramowi/Code/OpenSource/detect-secrets/detect_secrets/settings.py", line 266, in get_plugins
    return [
           ^
  File "/Users/abramowi/Code/OpenSource/detect-secrets/detect_secrets/settings.py", line 267, in <listcomp>
    plugins.initialize.from_plugin_classname(classname)
  File "/Users/abramowi/Code/OpenSource/detect-secrets/detect_secrets/core/plugins/initialize.py", line 34, in from_plugin_classname
    for plugin_type in get_mapping_from_secret_type_to_class().values():
                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/abramowi/Code/OpenSource/detect-secrets/detect_secrets/core/plugins/util.py", line 43, in get_mapping_from_secret_type_to_class
    for plugin_class in get_plugins_from_file(filename):
  File "/Users/abramowi/Code/OpenSource/detect-secrets/detect_secrets/core/plugins/util.py", line 51, in get_plugins_from_file
    for plugin_class in get_plugins_from_module(import_file_as_module(filename)):
                                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/abramowi/Code/OpenSource/detect-secrets/detect_secrets/util/importlib.py", line 88, in import_file_as_module
    raise FileNotFoundError
FileNotFoundError

[msabramo]

With #719, the output is:

$ detect-secrets-hook --baseline .secrets.baseline setup.py
[initialize]	ERROR	Error: Failed to load `FakeCustomPlugin` plugin:
    [Errno 2] No such file or directory: './path/to/plugin/that/does/not/exist/plugin.py'
[initialize]	ERROR	This error can occur when using a baseline that references a custom plugin
    with a path that does not exist.
[scan]	ERROR	Unable to load plugins!

which is much more useful for troubleshooting!