New submission from Pekka Klärck <pekka.kla...@gmail.com>: We have implemented an ast for our own tool so that we extend Python's standard `ast.AST`. When using `ast.dump(node, include_attributes=True)`, we were surprised to notice that line numbers weren't dumped although the docs of `ast.dump()` said they should be and we had set both `lineno` and `end_lineno` attributes to our nodes.
Looking at the implementation of `ast.dump()` revealed that `include_attributes=True` alone wasn't enough, the node also needed to have `_attributes` attribute similarly as it needs to have `_fields` for `ast.dump()` to be able to dump also child nodes. The problem is that `_attributes` isn't documented at all. Related to that, `ast.dump()` using `_fields` isn't documented either, but at least `_fields` is mentioned in the docs otherwise. Relevant links to `ast.dump()` docs and to the source code below. `ast.AST` documents the `_fields` attribute but doesn't mention similar `_attributes`: https://docs.python.org/3/library/ast.html#ast.AST `ast.dump()` documents the `include_attributes` argument but doesn't mention that `_attributes` is needed (or that `_fields` needs to be set correctly to get child notes dumped): https://docs.python.org/3/library/ast.html#ast.dump `ast.dump()` source code shows that the undocumented `_attributes` needs to be set in addition to using `include_attributes=True`: https://github.com/python/cpython/blob/3.8/Lib/ast.py#L123 ---------- messages: 356362 nosy: pekka.klarck priority: normal severity: normal status: open title: `ast.AST._attributes` is used by `ast.dump()` but not documented _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue38765> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
