collect_schema() succeeds for arr.* functions on non-array columns #25648
Description
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- I have checked that this issue has not already been reported.
- I have confirmed this bug exists on the latest version of Polars.
Issue Description
Calls to collect_schema() when the .arr namespace is applied to non-array columns succeed when they should error.
import polars as pl
lf = pl.LazyFrame({"a": ["a", "b", "c"]})
a = pl.col("a")
# The following raise an exception, as they should.
lf.select(a.arr.contains("z")).collect_schema() # ERROR - OK
lf.select(a.arr.explode()).collect_schema() # ERROR - OK
lf.select(a.arr.agg(pl.element().len())).collect_schema() # ERROR - OK
lf.select(a.arr.eval(pl.element().len())).collect_schema() # ERROR - OK
lf.select(a.arr.sum()).collect_schema() # ERROR - OK
lf.select(a.arr.to_list()).collect_schema() # ERROR - OK
lf.select(a.arr.to_struct()).collect_schema() # ERROR - OK
lf.select(a.arr.unique()).collect_schema() # ERROR - OK
# The following succeed when they should raise an exception.
lf.select(a.arr.all()).collect_schema() # Schema({'a': Boolean})
lf.select(a.arr.any()).collect_schema() # Schema({'a': Boolean})
lf.select(a.arr.arg_max()).collect_schema() # Schema({'a': UInt32})
lf.select(a.arr.arg_min()).collect_schema() # Schema({'a': UInt32})
lf.select(a.arr.count_matches("z")).collect_schema() # Schema({'a': UInt32})
lf.select(a.arr.first()).collect_schema() # Schema({'a': Unknown})
lf.select(a.arr.get(0)).collect_schema() # Schema({'a': Unknown})
lf.select(a.arr.join("")).collect_schema() # Schema({'a': String})
lf.select(a.arr.last()).collect_schema() # Schema({'a': Unknown})
lf.select(a.arr.len()).collect_schema() # Schema({'a': Unknown})
lf.select(a.arr.max()).collect_schema() # Schema({'a': Unknown})
lf.select(a.arr.mean()).collect_schema() # Schema({'a': String})
lf.select(a.arr.median()).collect_schema() # Schema({'a': String})
lf.select(a.arr.min()).collect_schema() # Schema({'a': Unknown})
lf.select(a.arr.n_unique()).collect_schema() # Schema({'a': UInt32})
lf.select(a.arr.reverse()).collect_schema() # Schema({'a': String})
lf.select(a.arr.shift(1)).collect_schema() # Schema({'a': String})
lf.select(a.arr.sort()).collect_schema() # Schema({'a': String})
lf.select(a.arr.std()).collect_schema() # Schema({'a': String})
lf.select(a.arr.var()).collect_schema() # Schema({'a': String})Installed versions
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