make xml module easier to work with #14674
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Pyright is failing on xml.etree.ElementTree users in our third party stubs that now are lacking type arguments for Element. I can fix those up easily enough, but I'll wait for opinions about the direction of this MR before I do that. |
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Diff from mypy_primer, showing the effect of this PR on open source code: openlibrary (https://github.com/internetarchive/openlibrary)
+ openlibrary/i18n/test_po_files.py: note: In function "test_html_format":
+ openlibrary/i18n/test_po_files.py:82: error: Need type annotation for "id_tree" [var-annotated]
+ openlibrary/i18n/test_po_files.py:83: error: Need type annotation for "str_tree" [var-annotated]
colour (https://github.com/colour-science/colour)
+ colour/io/tm2714.py:1690: error: Need type annotation for "tree" [var-annotated]
sphinx (https://github.com/sphinx-doc/sphinx)
+ sphinx/testing/util.py: note: In function "etree_parse":
+ sphinx/testing/util.py:79:50: error: Missing type parameters for generic type "ElementTree" [type-arg]
+ sphinx/ext/graphviz.py: note: In function "fix_svg_relative_paths":
+ sphinx/ext/graphviz.py:242:12: error: Need type annotation for "tree" [var-annotated]
materialize (https://github.com/MaterializeInc/materialize)
- misc/python/materialize/cli/gen-chroma-syntax.py:56: error: Incompatible types in assignment (expression has type "Element[str] | None", variable has type "Element[str]") [assignment]
+ misc/python/materialize/cli/gen-chroma-syntax.py:56: error: Incompatible types in assignment (expression has type "Element[Any] | None", variable has type "Element[Any]") [assignment]
+ misc/python/materialize/cli/gen-chroma-syntax.py:70: error: Need type annotation for "tree" [var-annotated]
boostedblob (https://github.com/hauntsaninja/boostedblob)
+ boostedblob/xml.py:15: error: Missing type parameters for generic type "Element" [type-arg]
+ boostedblob/azure_auth.py:286: error: Need type annotation for "result" [var-annotated]
+ boostedblob/azure_auth.py:573: error: Need type annotation for "result" [var-annotated]
+ boostedblob/request.py:271: error: Missing type parameters for generic type "Element" [type-arg]
+ boostedblob/request.py:287: error: Need type annotation for "result" [var-annotated]
+ boostedblob/listing.py:394: error: Missing type parameters for generic type "Element" [type-arg]
+ boostedblob/write.py:355: error: Need type annotation for "result" [var-annotated]
+ boostedblob/write.py:446: error: Need type annotation for "result" [var-annotated]
+ boostedblob/_recover.py:20: error: Missing type parameters for generic type "Element" [type-arg]
python-chess (https://github.com/niklasf/python-chess)
+ chess/svg.py:151: error: Missing type parameters for generic type "Element" [type-arg]
+ chess/svg.py:185: error: Missing type parameters for generic type "Element" [type-arg]
mkosi (https://github.com/systemd/mkosi)
+ mkosi/distributions/opensuse.py:259:12: error: Need type annotation for "root" [var-annotated]
pytest (https://github.com/pytest-dev/pytest)
+ src/_pytest/junitxml.py:94: error: Missing type parameters for generic type "Element" [type-arg]
+ src/_pytest/junitxml.py:97: error: Missing type parameters for generic type "Element" [type-arg]
+ src/_pytest/junitxml.py:107: error: Missing type parameters for generic type "Element" [type-arg]
+ src/_pytest/junitxml.py:146: error: Missing type parameters for generic type "Element" [type-arg]
+ src/_pytest/junitxml.py:685: error: Missing type parameters for generic type "Element" [type-arg]
cloud-init (https://github.com/canonical/cloud-init)
+ cloudinit/sources/helpers/azure.py:382: error: Need type annotation for "root" [var-annotated]
+ cloudinit/sources/helpers/azure.py:1026: error: Need type annotation for "root" [var-annotated]
meson (https://github.com/mesonbuild/meson)
+ mesonbuild/modules/_qt.py:309:20: error: Need type annotation for "tree" [var-annotated]
discord.py (https://github.com/Rapptz/discord.py)
- discord/ext/commands/hybrid.py:508: error: Overlap between argument names and ** TypedDict items: "description", "name" [misc]
+ discord/ext/commands/hybrid.py:508: error: Overlap between argument names and ** TypedDict items: "name", "description" [misc]
- discord/ext/commands/hybrid.py:629: error: Overlap between argument names and ** TypedDict items: "description", "name" [misc]
+ discord/ext/commands/hybrid.py:629: error: Overlap between argument names and ** TypedDict items: "name", "description" [misc]
- discord/ext/commands/hybrid.py:834: error: Overlap between argument names and ** TypedDict items: "with_app_command", "name" [misc]
+ discord/ext/commands/hybrid.py:834: error: Overlap between argument names and ** TypedDict items: "name", "with_app_command" [misc]
- discord/ext/commands/hybrid.py:858: error: Overlap between argument names and ** TypedDict items: "with_app_command", "name" [misc]
+ discord/ext/commands/hybrid.py:858: error: Overlap between argument names and ** TypedDict items: "name", "with_app_command" [misc]
- discord/ext/commands/hybrid.py:883: error: Overlap between argument names and ** TypedDict items: "with_app_command", "name" [misc]
+ discord/ext/commands/hybrid.py:883: error: Overlap between argument names and ** TypedDict items: "name", "with_app_command" [misc]
- discord/ext/commands/hybrid.py:935: error: Overlap between argument names and ** TypedDict items: "with_app_command", "name" [misc]
+ discord/ext/commands/hybrid.py:935: error: Overlap between argument names and ** TypedDict items: "name", "with_app_command" [misc]
- discord/ext/commands/bot.py:290: error: Overlap between argument names and ** TypedDict items: "with_app_command", "name" [misc]
+ discord/ext/commands/bot.py:290: error: Overlap between argument names and ** TypedDict items: "name", "with_app_command" [misc]
- discord/ext/commands/bot.py:314: error: Overlap between argument names and ** TypedDict items: "with_app_command", "name" [misc]
+ discord/ext/commands/bot.py:314: error: Overlap between argument names and ** TypedDict items: "name", "with_app_command" [misc]
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tungol
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Sep 5, 2025
This is an alternative to python#14674 While investigating, I also noticed that QName classes can be the value of both Element.tag and Eelement.text, as well in the result of Element.items() (and thus as keys and values in Element.attrib). The test suite in cpython also includes explict tests for assigning None to Element.tag as a form of suppressing it, so I added that into the annotation as well.
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See #14678 for what it looks like if we commit to the type of Element.tag being a union of a bunch of stuff |
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Changes:
_Tag, soElementis nowElement[Any]instead ofElement[str]._Tagobscuring where things were missed_AnyTagisn't strictly needed, but may be convenient for interested end users_Tagnow instead ofTypeVar(_Root, bound=Element[Any] | None). TheNonecase is marginal and can be ignored. The variable represents the type of the tag attribute of elements within the tree._Tag. Ideally, it should beTreeBuilder[str]when bothinsert_commentsandinsert_pisare False, andTreeBuilder[_AnyTag]when either is true, but it wasn't possible to do something like this based on the__init__method last time I tried. I don't know if this is worth doing without that.XMLParser is unchanged, but worth noting because I'm not happy with it still. I don't know if it can be improved given how much duck typing is at work there, but I might take another crack at it later.
@hterik if you're able to try these stubs out against your code, can you let me know what pain points remain? You can clone this branch of typeshed down to your local machine, and tell mypy to use it with
mypy --custom-typeshed-dir path/to/typeshed/repoI don't have a lot of experience using the xml module myself, so your input is very useful.
I am also open to the idea that all of this typevar stuff was a bad idea in the first place - the main thing it's trying to do is save users from needing to guard against
ET.CommentandET.ProcessingInstructionwhen working with Elements that only contain string tags. It'd save a lot of complexity in the stubs if we bite the bullet on that and just typeElement.tagasstr | _ElementCallableuniversally. My intuition was that that would be a frequent papercut annoyance, but maybe the problems introduced by trying to be fancy about it are worse, actually.