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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"ResourceReader API can't be implemented for zipimporter","articleBody":"In GitLab by @warsaw on Jan 2, 2018, 13:25\n\nThe `ResourceReader` APIs only take a single `resource` argument, but this is incompatible with the current implementation of zipimporter.  The problem is that, unlike with file-based modules, all modules imported from a zip file share the same loader:\n\n```python\n\u003e\u003e\u003e import test.test_importlib.zipdata02\n\u003e\u003e\u003e import sys, os\n\u003e\u003e\u003e sys.path.insert(0, os.path.join(os.path.dirname(test.test_importlib.zipdata02.__file__), 'ziptestdata.zip'))\n\u003e\u003e\u003e import ziptestdata.two\n\u003e\u003e\u003e import ziptestdata.one\n\u003e\u003e\u003e ziptestdata.one.__spec__.loader == ziptestdata.two.__spec__.loader\nTrue\n```\n\nSo let's say you have a resource called `myresource.txt` in `ziptestdata.two` and `ziptestdata.one`.  The implementation of [ResourceReader.open_resource()](https://github.com/python/cpython/blob/master/Lib/importlib/abc.py#L350) on the zipimporter's loader can't possibly know which `myresource.txt` file is being requested.\n\n@brettcannon mentioned PEP 302's design decision not to require a unique loader instance per module, and wanted to move away from that, but I think we're stuck with requiring a `package` argument to the `ResourceReader`.  The only other option would be to change zipimporter to provide a unique loader instance per module, but that seems like a backward compatibility break.  Besides, if other 3rd party loaders follow the same implementation of a shared loader, they won't be able to implement `ResourceReader` either.","author":{"url":"https://github.com/jaraco","@type":"Person","name":"jaraco"},"datePublished":"2020-10-21T21:55:41.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":13},"url":"https://github.com/49/importlib_resources/issues/49"}