Ruff fails when a directory ends with .py

[konstin]

Ruff gets confused when a directory is named like a python file (ends with .py):

$ mkdir repro
$ mkdir repro/some_folder.py
$ cargo run --bin ruff -- --no-cache repro
error: Failed to lint repro/some_folder.py: Is a directory (os error 21)
  Caused by: Is a directory (os error 21)
repro/some_folder.py:1:1: E902 Is a directory (os error 21)
  Caused by: Is a directory (os error 21)
Found 1 error.

[zanieb]

@konstin is this a good first issue?

[charliermarsh]

(From my perspective, seems like a good issue, will probably require digging into how we collect the "files to lint".)

[konstin]

i've confirmed it's not related to #5611, so yes it's a good first issue

[harupy]

can I work on this?

[harupy]

Is this the part that needs to be fixed?

ruff/crates/ruff/src/resolver.rs

Lines 332 to 350 in f029f8b

	if result.as_ref().map_or(true, |entry| {
	if entry.depth() == 0 {
	// Accept all files that are passed-in directly.
	entry.file_type().map_or(false, |ft| ft.is_file())
	} else {
	// Otherwise, check if the file is included.
	let path = entry.path();
	let resolver = resolver.read().unwrap();
	let settings = resolver.resolve(path, pyproject_config);
	if settings.include.is_match(path) {
	debug!("Included path via `include`: {:?}", path);
	true
	} else if settings.extend_include.is_match(path) {
	debug!("Included path via `extend-include`: {:?}", path);
	true
	} else {
	false
	}
	}

It looks like the else block is missing is_file check.

[harupy]

Testing the following change:

diff --git a/crates/ruff/src/resolver.rs b/crates/ruff/src/resolver.rs
index 0ad0fa244..0d851135c 100644
--- a/crates/ruff/src/resolver.rs
+++ b/crates/ruff/src/resolver.rs
@@ -330,9 +330,12 @@ pub fn python_files_in_path(
             }
 
             if result.as_ref().map_or(true, |entry| {
+                if !(entry.file_type().map_or(false, |ft| ft.is_file())) {
+                    return false;
+                }
                 if entry.depth() == 0 {
                     // Accept all files that are passed-in directly.
-                    entry.file_type().map_or(false, |ft| ft.is_file())
+                    true
                 } else {
                     // Otherwise, check if the file is included.
                     let path = entry.path();

Result:

> tree dir
dir
├── dir.py
│   └── file.py
└── file.py

1 directory, 2 files

> cargo run -p ruff_cli -- check dir --no-cache
    Finished dev [unoptimized + debuginfo] target(s) in 0.08s
     Running `target/debug/ruff check dir --no-cache`
dir/dir.py/file.py:1:7: F821 Undefined name `a`
dir/file.py:1:7: F821 Undefined name `a`
Found 2 errors.