ARM64 Linux download error for release (candidate) builds

[juj]

I am trying to download latest Firefox on ARM64, with

mozdownload --version=latest --platform linux-arm64

and I get

Traceback (most recent call last):
  File "/home/clb/.pyenv/versions/3.13.3/bin/mozdownload", line 8, in <module>
    sys.exit(cli())
             ~~~^^
  File "/home/clb/.pyenv/versions/3.13.3/lib/python3.13/site-packages/mozdownload/cli.py", line 172, in cli
    build.download()
    ~~~~~~~~~~~~~~^^
  File "/home/clb/.pyenv/versions/3.13.3/lib/python3.13/site-packages/mozdownload/scraper.py", line 308, in download
    if os.path.isfile(os.path.abspath(self.filename)):
                                      ^^^^^^^^^^^^^
  File "/home/clb/.pyenv/versions/3.13.3/lib/python3.13/site-packages/mozdownload/scraper.py", line 272, in filename
    self.build_filename(self.binary))
                        ^^^^^^^^^^^
  File "/home/clb/.pyenv/versions/3.13.3/lib/python3.13/site-packages/mozdownload/scraper.py", line 222, in binary
    self._retry_check_404(_get_binary)
    ~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^
  File "/home/clb/.pyenv/versions/3.13.3/lib/python3.13/site-packages/mozdownload/scraper.py", line 187, in _retry_check_404
    self._retry(func, **retry_kwargs)
    ~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^
  File "/home/clb/.pyenv/versions/3.13.3/lib/python3.13/site-packages/mozdownload/scraper.py", line 178, in _retry
    return redo.retry(func, **retry_kwargs)
           ~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^
  File "/home/clb/.pyenv/versions/3.13.3/lib/python3.13/site-packages/redo/__init__.py", line 172, in retry
    return action(*args, **kwargs)
  File "/home/clb/.pyenv/versions/3.13.3/lib/python3.13/site-packages/mozdownload/scraper.py", line 210, in _get_binary
    pattern = re.compile(self.binary_regex, re.IGNORECASE)
                         ^^^^^^^^^^^^^^^^^
  File "/home/clb/.pyenv/versions/3.13.3/lib/python3.13/site-packages/mozdownload/scraper.py", line 701, in binary_regex
    return regex[self.platform] % {
           ~~~~~^^^^^^^^^^^^^^^
KeyError: 'linux-arm64'

Adding this line seems to help:

[juj]

Btw it would be nice for the platform name to be just arm64 rather than linux-arm64. That way on CI environments on Windows one could reuse the same --platform string as Linux (rather than having to if over Linux vs Windows)

Also, it would be useful if by default the downloader would get the same artifact as the host system, if platform is not specified. So for example on Linux on ARM64, the downloader would by default get ARM64 artifacts if nothing else is specified. E.g. Debian 13 on ARM64 at least will not use any kind of x86-on-arm emulator to run the default-downloaded x64 artifact.. so the default mozdownload --version=latest will download an unusable x64 binary on ARM64 otherwise.

[whimboo]

Btw it would be nice for the platform name to be just arm64 rather than linux-arm64. That way on CI environments on Windows one could reuse the same --platform string as Linux (rather than having to if over Linux vs Windows)

We cannot just have the arm64 variant given that would not allow to download arm64 builds for Linux from a Windows host. But we could imagine to have a synonym which checks the current platform and downloads the appropriate version. Would you mind filing a separate issue for that?

Also, it would be useful if by default the downloader would get the same artifact as the host system, if platform is not specified. So for example on Linux on ARM64, the downloader would by default get ARM64 artifacts if nothing else is specified. E.g. Debian 13 on ARM64 at least will not use any kind of x86-on-arm emulator to run the default-downloaded x64 artifact.. so the default mozdownload --version=latest will download an unusable x64 binary on ARM64 otherwise.

This is a bug in platform detection most likely. We should extend that particular code to not only check for windows vs. linux but as well the arm64 bit. Please file a separate issue for this request as well.