[Python-Dev] PEP 302 and 'reload()' (original) (raw)

Phillip J. Eby pje at telecommunity.com
Thu Sep 16 23:14:07 CEST 2004

At 05:38 PM 9/8/04 -0400, Phillip J. Eby wrote:

It appears to me there is an error in both PEP 302's specification and its implementation concerning the correct operation of reload(). First, it says:

The loadmodule() method has a few responsibilities that it must fulfill before it runs any code: - It must create the module object. From Python this can be done via the new.module() function, the imp.newmodule() function or via the module type object; from C with the PyModuleNew() function or the PyImportModuleAdd() function. This should probably say that if the module already exists in sys.modules, it should reuse the existing module object, rather than creating a new one. Otherwise, 'reload()' cannot fulfill its contract. Second, the actual implementation of PyImportReloadModule doesn't actually use a loader object, so reload() doesn't work with import hooks at all. There's an SF bug report for this, and a patch to fix it (that also adds a test to testimporthooks to ensure that 'reload()' actually invokes the loader. Are there any objections to me fixing either/both of these, and backporting the bugfix to the 2.3 maintenance branch?

Since there have been no objections, I'll undertake (schedule permitting) to correct PEP 302, fix PyImport_ReloadModule and Lib/test/test_importhooks, and backport the changes.

I'll note that there are other issues that affect reloading from e.g. zipfiles, but those are over my head to tackle at present. However, until the PEP 302-level issues are dealt with, there's no chance of fixing reload-from-zip, since the underlying reload mechanism itself is broken with respect to PEP 302.

Also, should PyImportReloadModule use the import lock? It doesn't currently, but I'm not clear on why it doesn't.

Since noone has answered this, I'll have to assume that there is a good reason, and won't fiddle with it. But I'd still appreciate an answer.

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