Running scancode-license-data without arguments does not work

[sschuberth]

Description

Running scancode-license-data that comes with 32.3.0 does not work.

How To Reproduce

1. Install scancode-toolkit version 32.3.0.
2. Run scancode-license-data without any arguments.
3. See

$ scancode-license-data
Dumping license data to: None
Traceback (most recent call last):
  File "/opt/python/versions/3.11.10/bin/scancode-license-data", line 8, in <module>
    sys.exit(dump_scancode_license_data())
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/python/versions/3.11.10/lib/python3.11/site-packages/click/core.py", line 1157, in __call__
    return self.main(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/python/versions/3.11.10/lib/python3.11/site-packages/click/core.py", line 1078, in main
    rv = self.invoke(ctx)
         ^^^^^^^^^^^^^^^^
  File "/opt/python/versions/3.11.10/lib/python3.11/site-packages/click/core.py", line 1434, in invoke
    return ctx.invoke(self.callback, **ctx.params)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/python/versions/3.11.10/lib/python3.11/site-packages/click/core.py", line 783, in invoke
    return __callback(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/python/versions/3.11.10/lib/python3.11/site-packages/licensedcode/license_db.py", line 227, in dump_scancode_license_data
    scancode_license_data(path=path)
  File "/opt/python/versions/3.11.10/lib/python3.11/site-packages/licensedcode/license_db.py", line 204, in scancode_license_data
    count = generate(build_location=path)
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/python/versions/3.11.10/lib/python3.11/site-packages/licensedcode/license_db.py", line 175, in generate
    if not os.path.exists(build_location):
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<frozen genericpath>", line 19, in exists
TypeError: stat: path should be string, bytes, os.PathLike or integer, not NoneType

The same happens on another machine with Python 3.13:

Dumping license data to: None
Traceback (most recent call last):
  File "/usr/bin/scancode-license-data", line 8, in <module>
    sys.exit(dump_scancode_license_data())
             ~~~~~~~~~~~~~~~~~~~~~~~~~~^^
  File "/usr/lib/python3.13/site-packages/click/core.py", line 1157, in __call__
    return self.main(*args, **kwargs)
           ~~~~~~~~~^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.13/site-packages/click/core.py", line 1078, in main
    rv = self.invoke(ctx)
  File "/usr/lib/python3.13/site-packages/click/core.py", line 1434, in invoke
    return ctx.invoke(self.callback, **ctx.params)
           ~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.13/site-packages/click/core.py", line 783, in invoke
    return __callback(*args, **kwargs)
  File "/usr/lib/python3.13/site-packages/licensedcode/license_db.py", line 227, in dump_scancode_license_data
    scancode_license_data(path=path)
    ~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^
  File "/usr/lib/python3.13/site-packages/licensedcode/license_db.py", line 204, in scancode_license_data
    count = generate(build_location=path)
  File "/usr/lib/python3.13/site-packages/licensedcode/license_db.py", line 175, in generate
    if not os.path.exists(build_location):
           ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^
  File "<frozen genericpath>", line 19, in exists
TypeError: stat: path should be string, bytes, os.PathLike or integer, not NoneType

System configuration

• What OS are you running on? Linux
• What version of scancode-toolkit was used to generate the scan file? 32.3.0
• What installation method was used to install/run scancode? Both RPM package on Fedora and pip install.

[AyanSinhaMahapatra]

@sschuberth please refer to the help text for the command:

scancode-license-data --help
Usage: scancode-license-data [OPTIONS]

  Dump scancode license data in various formats, and the licenseDB static
  website at `path`.

Options:
  --path DIR  Dump the license data in this directory in the LicenseDB format
              and exit. Creates the directory if it does not exist.
  -h, --help  Show this message and exit.

The code is at https://github.com/aboutcode-org/scancode-toolkit/blob/develop/src/licensedcode/license_db.py#L208 btw, as indicated in the traceback.

I think you are not providing the --path <path _to_dump_licenses> option which is causing the issue.
I could do a simple pip install for the latest scancode and this does work allright.

python3 -m venv scancode-32.3
source scancode-32.3/bin/activate
pip install scancode-toolkit==32.3.0
scancode-license-data --help
scancode-license-data --path license-data

Maybe this confusion was caused by inadequate docs? This should probably be included in https://scancode-toolkit.readthedocs.io/en/stable/cli-reference/other-commands.html which is at https://github.com/aboutcode-org/scancode-toolkit/blob/develop/docs/source/cli-reference/other-commands.rst

If you can confirm this, it would be great. We can then convert the issue to enhance the docs on this.

[sschuberth]

I can confirm that both scancode-license-data --help and scancode-license-data --path license-data work, but my point is that just running scancode-license-data (without arguments) should not crash. Instead, it should probably just print the help as well.

[AyanSinhaMahapatra]

We could add more documentation as suggested in #4024 (comment) and probably print a statement to provide path/nudge towards running the help text if someone does not provide a path.

[sschuberth]

As no one reads docs, I indeed recommend to "build-in the docs" by making the tool print something meaningful in this case. Thanks!

[pombredanne]

The simplest way is to make the option required with a required=True arg at

scancode-toolkit/src/licensedcode/license_db.py

Line 212 in c40476a

metavar='DIR',

[lyr-ast]

could you look at my pr and see if its fit for merging #4029