Add support for other systemic aliases specified in CLDR root.xml - #1310
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akx
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Add support for other systemic aliases specified in CLDR root.xmlroot.xml
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## master #1310 +/- ##
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+ Coverage 92.19% 92.20% +0.01%
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Files 27 27
Lines 4764 4761 -3
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+ Misses 372 371 -1
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Pull request overview
This PR extends Babel’s CLDR import and locale-data resolution to ingest additional systemic <alias> rules from CLDR root.xml, so missing length variants (units, date fields, compact decimals, currency formats) resolve via aliases rather than ad-hoc fallbacks—eliminating some rare KeyError crashes and improving formatting in edge cases.
Changes:
- Import and materialize additional CLDR
root.xmlalias relationships duringscripts/import_cldr.pyingestion (decimal formats, unit lengths/unit aliases, date field aliases). - Enhance locale-data alias resolution/merging in
babel/localedata.pyto support “alias + dict overrides” safely. - Simplify unit and timedelta formatting lookups to rely on alias-resolving locale data instead of hard-coded fallbacks, with new regression tests covering the reported cases.
Reviewed changes
Copilot reviewed 7 out of 7 changed files in this pull request and generated 2 comments.
Show a summary per file
| File | Description |
|---|---|
| scripts/import_cldr.py | Imports additional CLDR root.xml aliases (decimal formats, unit patterns/display names, date fields) into generated locale data. |
| babel/localedata.py | Extends merge + alias resolution to support dict overrides layered on top of aliases. |
| babel/units.py | Switches format_unit to rely on alias-resolving locale data for length fallback/alias behavior. |
| babel/dates.py | Switches format_timedelta unit/date-field lookup to rely on alias-resolving locale data and avoids a direct KeyError path. |
| tests/test_units.py | Adds regression tests for unit aliases, length aliases, and person-variant alias behavior. |
| tests/test_numbers.py | Adds regression tests for compact decimal and currency format aliasing. |
| tests/test_dates.py | Adds regression tests for date field length aliasing and missing-pattern edge cases. |
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tomasr8
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Jul 31, 2026
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Not super familiar with this, but nothing jumps out at me. The comments were very helpful though :)
| elif isinstance(data, tuple): | ||
| alias, others = data | ||
| data = alias.resolve(base) | ||
| if others: # Apply overrides on a copy. |
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Sorry, I'm not that familiar with this part of the codebase - why is this needed? And should it be tested?
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others were simply ignored, which caused some chains of override/alias to fail (which are needed here).
There's an explicit test now :)
We had some manual fallbacks for missing field/unit lengths, and ignored many `<alias>`es in CLDR data entirely. This PR imports those aliases and uses them to resolve missing lengths, improving output in corner cases and fixes some rare KeyError crashes too. There's a quirk related to person-variant unit aliases, which are only expressed in CLDR for the short length. If one follows the spec to the letter, a request for a long/narrow person-variant unit will route through the short length and lose the requested length. We use the same "workaround" as ICU to preserve the length, by importing these as whole-unit aliases. Not totally spec- compliant, but the end result is simply better. Fixes #1076
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We had some manual fallbacks for missing field/unit lengths, and ignored many
<alias>es in CLDR data entirely.This PR imports those aliases and uses them to resolve missing lengths, improving output in corner cases and fixes some rare KeyError crashes too.
There's a quirk related to person-variant unit aliases, which are only expressed in CLDR for the short length. If one follows the spec to the letter, a request for a long/narrow person-variant unit will route through the short length and lose the requested length.
We use the same "workaround" as ICU to preserve the length, by importing these as whole-unit aliases. Not totally spec-compliant, but the end result is simply better.
Fixes #1076.