Fix an issue trying list.index indexing in FusedNode

[da-woods]

In some Python versions, generating the error message when .index fails to find an index leads to a compiler crash.

Fix this by not relying on type being fully set up while generating __repr__.

Fixes #5894 and #5588

[scoder]

This fixes the symptom, but it seems worth investigating where we use this. Maybe we don't actually need to call the function to display the type there? Maybe we can do something else instead? Swallowing errors always risks hiding other errors, that was the reason for the change in CPython as well.

[da-woods]

cython/Cython/Compiler/FusedNode.py

Lines 199 to 204 in 02ddde3

	try:
	cindex = env.cfunc_entries.index(self.node.entry)
	except ValueError:
	env.cfunc_entries.extend(new_cfunc_entries)
	else:
	env.cfunc_entries[cindex:cindex+1] = new_cfunc_entries

We find the index of an entry in a list. If the index isn't found then Python calls __repr__ of the entry (and thus __repr__ of the type) as part of preparing the ValueError.

It could probably be rewritten to do an in test before finding the index

[scoder]

It could probably be rewritten to do an in test before finding the index

Yes, that seems better.

[da-woods]

I backported to 0.29.x because it looked like it would be an issue there too.

0.29.x: 35247a0
3.0.x 66a6be1