feat: Use better error messages when opening files (#20307)

crates/polars-io/src/partition.rs

@@ -5,6 +5,7 @@ use std::path::Path;
 use polars_core::prelude::*;
 use polars_core::series::IsSorted;
 use polars_core::POOL;
+use polars_utils::create_file;
 use rayon::prelude::*;
 
 use crate::parquet::write::ParquetWriteOptions;
@@ -110,7 +111,7 @@ where
     };
 
     let write_part = |df: DataFrame, path: &Path| {
-        let f = std::fs::File::create(path)?;
+        let f = create_file(path)?;
         file_write_options.write_df_to_file(df, f)?;
         PolarsResult::Ok(())
     };

crates/polars-io/src/utils/file.rs

@@ -1,7 +1,9 @@
 use std::io::Write;
+use std::path::Path;
 
 use polars_core::config;
-use polars_error::{feature_gated, PolarsError, PolarsResult};
+use polars_error::{feature_gated, PolarsResult};
+use polars_utils::create_file;
 use polars_utils::mmap::ensure_not_mapped;
 
 use crate::cloud::CloudOptions;
@@ -24,8 +26,7 @@ pub fn try_get_writeable(
             }
 
             if path.starts_with("file://") {
-                std::fs::File::create(&path[const { "file://".len() }..])
-                    .map_err(PolarsError::from)?;
+                create_file(Path::new(&path[const { "file://".len() }..]))?;
             }
 
             let writer = crate::pl_async::get_runtime()
@@ -45,7 +46,7 @@ pub fn try_get_writeable(
                 )
             }
 
-            std::fs::File::create(&path).map_err(PolarsError::from)?;
+            create_file(&path)?;
             let path = std::fs::canonicalize(&path)?;
 
             ensure_not_mapped(&path.metadata()?)?;
@@ -69,7 +70,7 @@ pub fn try_get_writeable(
         })
     } else {
         let path = resolve_homedir(&path);
-        std::fs::File::create(&path).map_err(PolarsError::from)?;
+        create_file(&path)?;
 
         if verbose {
             eprintln!(

crates/polars-mem-engine/src/executors/scan/ipc.rs

@@ -6,6 +6,7 @@ use polars_io::cloud::CloudOptions;
 use polars_io::path_utils::is_cloud_url;
 use polars_io::predicates::apply_predicate;
 use polars_utils::mmap::MemSlice;
+use polars_utils::open_file;
 use rayon::prelude::*;
 
 use super::*;
@@ -77,7 +78,7 @@ impl IpcExec {
             let memslice = match source {
                 ScanSourceRef::Path(path) => {
                     let file = match idx_to_cached_file(index) {
-                        None => std::fs::File::open(path)?,
+                        None => open_file(path)?,
                         Some(f) => f?,
                     };
 

crates/polars-python/src/batched_csv.rs

@@ -5,6 +5,7 @@ use polars::io::csv::read::OwnedBatchedCsvReader;
 use polars::io::mmap::MmapBytesReader;
 use polars::io::RowIndex;
 use polars::prelude::*;
+use polars_utils::open_file;
 use pyo3::prelude::*;
 use pyo3::pybacked::PyBackedStr;
 
@@ -91,7 +92,7 @@ impl PyBatchedCsv {
                 .collect::<Vec<_>>()
         });
 
-        let file = std::fs::File::open(path).map_err(PyPolarsErr::from)?;
+        let file = open_file(&path).map_err(PyPolarsErr::from)?;
         let reader = Box::new(file) as Box<dyn MmapBytesReader>;
         let reader = CsvReadOptions::default()
             .with_infer_schema_length(infer_schema_length)

crates/polars-python/src/file.rs

@@ -12,6 +12,7 @@ use std::sync::Arc;
 use polars::io::mmap::MmapBytesReader;
 use polars_error::polars_err;
 use polars_io::cloud::CloudOptions;
+use polars_utils::create_file;
 use polars_utils::mmap::MemSlice;
 use pyo3::exceptions::PyTypeError;
 use pyo3::prelude::*;
@@ -350,7 +351,7 @@ fn get_either_buffer_or_path(
         if let Ok(s) = py_f.extract::<Cow<str>>() {
             let file_path = resolve_homedir(&&*s);
             let f = if write {
-                File::create(&file_path)?
+                create_file(&file_path).map_err(PyPolarsErr::from)?
             } else {
                 polars_utils::open_file(&file_path).map_err(PyPolarsErr::from)?
             };

py-polars/tests/unit/io/test_utils.py

@@ -1,9 +1,10 @@
 from __future__ import annotations
 
-from typing import TYPE_CHECKING
+from typing import TYPE_CHECKING, Any
 
 import pytest
 
+import polars as pl
 from polars.io._utils import looks_like_url, parse_columns_arg, parse_row_index_args
 
 if TYPE_CHECKING:
@@ -60,3 +61,11 @@ def test_parse_row_index_args() -> None:
 )
 def test_looks_like_url(url: str, result: bool) -> None:
     assert looks_like_url(url) == result
+
+
+@pytest.mark.parametrize(
+    "scan", [pl.scan_csv, pl.scan_parquet, pl.scan_ndjson, pl.scan_ipc]
+)
+def test_filename_in_err(scan: Any) -> None:
+    with pytest.raises(FileNotFoundError, match=r".*does not exist"):
+        scan("does not exist").collect()