[Distutils] tracking requested vs dependency installs in PEP 376 metadata

[exarkun at twistedmatrix.com]

On 01:45 pm, carl at dirtcircle.com wrote:
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>Alex wrote:
>>REQUESTED is fine, but I don't understand how the arguments apply, 
>>given
>> > that I'm not proposing to record information like _which_ package it 
>>was
>> > a dependency of. The same single bit (literally) of information is
>> > tracked either way, it's just a question of whether the presence or
>> > absence of a file signifies that bit.
>> >
>>And what if the package is a dependency for multiple packages?
>>Let's say we have packages A and B which are installed separately, in
>>that order, and both depend on C.
>>C gets installed with information that it was required by A. Now if A 
>>is
>>uninstalled, won't C also get uninstalled?
>
>No. We are NOT talking about recording the full dependency graph in
>package metadata. It is, as has always been the case, up to an 
>uninstall
>tool to calculate the depgraph based on actual installed packages at
>runtime. A package is "orphaned" iff it was not REQUESTED by the user
>AND it is no longer depended on by other installed packages.

By doing this, I think you're dooming any Python package uninstaller to 
be unpleasantly slow.

Jean-Paul