Symbolic links in wheels

Packaging
24

So I thought a bit about this, and it seems we’d need a wheel version bump for this? Because tools that work with the current wheel version are not guaranteed to be able to handle symlinks, so we need to signify what is compatible and what is not.

If that’s the case, a PEP should specify a new wheel version (1.1) that

  • Does everything that wheel version 1.0 does.
  • If a file in the wheel has external_attr bit 0xA0000000 set, the file MUST contain only one single line that contains a path relative to the directory containing the file. The path MUST point to another entry in the same wheel.
  • On installation, the install tool SHOULD create a symbolic link in place of the file with external_attr bit 0xA0000000 set, with the target being the wheel entry specified by the path in the file.
  • If an install tool is unable to create such a symbolic link, it MAY copy the target instead if the target is regular file. Otherwise, the install tool SHOULD signify this failure.
  • Build tools are advised to use wheel format 1.1 only if they need to include a symbolic link in the wheel, to maintain best compatibility with existing install tools.

I’ll begin drafting some text for the PEP if the above makes sense.

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