feat[python]: turn invalid datatype panic ot error (#4658)

pola-rs · Sep 1, 2022 · 96e897c · 96e897c
1 parent 467a663
commit 96e897c
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Showing 4 changed files with 34 additions and 15 deletions.
diff --git a/py-polars/src/conversion.rs b/py-polars/src/conversion.rs
@@ -322,7 +322,12 @@ impl FromPyObject<'_> for Wrap<DataType> {
                     "List" => DataType::List(Box::new(DataType::Boolean)),
                     "Null" => DataType::Null,
                     "Unknown" => DataType::Unknown,
-                    dt => panic!("{} not expected as Python type for dtype conversion", dt),
+                    dt => {
+                        return Err(PyValueError::new_err(format!(
+                            "{} is not a correct polars DataType.",
+                            dt
+                        )))
+                    }
                 }
             }
             "Duration" => {
@@ -352,10 +357,11 @@ impl FromPyObject<'_> for Wrap<DataType> {
                 DataType::Struct(fields)
             }
             dt => {
-                panic!(
-                    "{} not expected in Python dtype to Rust dtype conversion",
+                return Err(PyValueError::new_err(format!(
+                    "A {} object is not a correct polars DataType.\
+                 Hint: use the class without instantiating it.",
                     dt
-                )
+                )))
             }
         };
         Ok(Wrap(dtype))

diff --git a/py-polars/src/lazy/dsl.rs b/py-polars/src/lazy/dsl.rs
@@ -6,6 +6,7 @@ use polars::prelude::*;
 use polars::series::ops::NullBehavior;
 use polars_core::prelude::QuantileInterpolOptions;
 use pyo3::class::basic::CompareOp;
+use pyo3::exceptions::PyValueError;
 use pyo3::prelude::*;
 use pyo3::types::{PyBool, PyBytes, PyFloat, PyInt, PyString};
 
@@ -1667,34 +1668,38 @@ pub fn fold(acc: PyExpr, lambda: PyObject, exprs: Vec<PyExpr>) -> PyExpr {
     polars::lazy::dsl::fold_exprs(acc.inner, func, exprs).into()
 }
 
-pub fn lit(value: &PyAny) -> PyExpr {
+pub fn lit(value: &PyAny) -> PyResult<PyExpr> {
     if let Ok(true) = value.is_instance_of::<PyBool>() {
         let val = value.extract::<bool>().unwrap();
-        dsl::lit(val).into()
+        Ok(dsl::lit(val).into())
     } else if let Ok(int) = value.downcast::<PyInt>() {
         let val = int.extract::<i64>().unwrap();
 
         if val > 0 && val < i32::MAX as i64 || val < 0 && val > i32::MIN as i64 {
-            dsl::lit(val as i32).into()
+            Ok(dsl::lit(val as i32).into())
         } else {
-            dsl::lit(val).into()
+            Ok(dsl::lit(val).into())
         }
     } else if let Ok(float) = value.downcast::<PyFloat>() {
         let val = float.extract::<f64>().unwrap();
-        dsl::lit(val).into()
+        Ok(dsl::lit(val).into())
     } else if let Ok(pystr) = value.downcast::<PyString>() {
-        dsl::lit(
+        Ok(dsl::lit(
             pystr
                 .to_str()
                 .expect("could not transform Python string to Rust Unicode"),
         )
-        .into()
+        .into())
     } else if let Ok(series) = value.extract::<PySeries>() {
-        dsl::lit(series.series).into()
+        Ok(dsl::lit(series.series).into())
     } else if value.is_none() {
-        dsl::lit(Null {}).into()
+        Ok(dsl::lit(Null {}).into())
     } else {
-        panic!("could not convert value {:?} as a Literal", value)
+        let value = value.str()?;
+        Err(PyValueError::new_err(format!(
+            "could not convert value {:?} as a Literal",
+            value
+        )))
     }
 }
 

diff --git a/py-polars/src/lib.rs b/py-polars/src/lib.rs
@@ -96,7 +96,7 @@ fn dtype_str_repr(dtype: Wrap<DataType>) -> PyResult<String> {
 }
 
 #[pyfunction]
-fn lit(value: &PyAny) -> dsl::PyExpr {
+fn lit(value: &PyAny) -> PyResult<dsl::PyExpr> {
     dsl::lit(value)
 }
 

diff --git a/py-polars/tests/test_errors.py b/py-polars/tests/test_errors.py
@@ -2,6 +2,7 @@
 
 import io
 import typing
+from datetime import date
 
 import numpy as np
 import pytest
@@ -147,3 +148,10 @@ def test_getitem_errs() -> None:
         r"'foo' of type: '<class 'str'>'",
     ):
         df[{"some"}] = "foo"
+
+
+def test_err_bubbling_up_to_lit() -> None:
+    df = pl.DataFrame({"date": [date(2020, 1, 1)], "value": [42]})
+
+    with pytest.raises(ValueError):
+        df.filter(pl.col("date") == pl.Date("2020-01-01"))