Fix extension casing on windows

src/finder.rs

@@ -9,7 +9,7 @@ use regex::Regex;
 use std::borrow::Borrow;
 use std::env;
 use std::ffi::OsStr;
-#[cfg(feature = "regex")]
+#[cfg(any(feature = "regex", target_os = "windows"))]
 use std::fs;
 use std::iter;
 use std::path::{Path, PathBuf};
@@ -80,7 +80,9 @@ impl Finder {
             }
         };
 
-        Ok(binary_path_candidates.filter(move |p| binary_checker.is_valid(p)))
+        Ok(binary_path_candidates
+            .filter(move |p| binary_checker.is_valid(p))
+            .map(correct_casing))
     }
 
     #[cfg(feature = "regex")]
@@ -207,3 +209,24 @@ impl Finder {
             })
     }
 }
+
+#[cfg(target_os = "windows")]
+fn correct_casing(mut p: PathBuf) -> PathBuf {
+    if let (Some(parent), Some(file_name)) = (p.parent(), p.file_name()) {
+        if let Ok(iter) = fs::read_dir(parent) {
+            for e in iter.filter_map(std::result::Result::ok) {
+                if e.file_name().eq_ignore_ascii_case(file_name) {
+                    p.pop();
+                    p.push(e.file_name());
+                    break;
+                }
+            }
+        }
+    }
+    p
+}
+
+#[cfg(not(target_os = "windows"))]
+fn correct_casing(p: PathBuf) -> PathBuf {
+    p
+}

tests/basic.rs

@@ -67,6 +67,10 @@ impl TestFixture {
             bins.push(mk_bin(&p, BIN_NAME, "cmd").unwrap());
             paths.push(p);
         }
+        let p = tempdir.path().join("win-bin");
+        builder.create(&p).unwrap();
+        bins.push(mk_bin(&p, "win-bin", "exe").unwrap());
+        paths.push(p);
         TestFixture {
             tempdir,
             paths: env::join_paths(paths).unwrap(),
@@ -194,6 +198,17 @@ fn test_which_extension() {
     assert_eq!(_which(&f, &b).unwrap(), f.bins[2])
 }
 
+#[test]
+#[cfg(windows)]
+fn test_which_no_extension() {
+    let f = TestFixture::new();
+    let b = Path::new("win-bin");
+    let which_result = which::which_in(&b, Some(&f.paths), ".").unwrap();
+    // Make sure the extension is the correct case.
+    assert_eq!(which_result.extension(), f.bins[9].extension());
+    assert_eq!(fs::canonicalize(&which_result).unwrap(), f.bins[9])
+}
+
 #[test]
 fn test_which_not_found() {
     let f = TestFixture::new();
@@ -221,6 +236,7 @@ fn test_which_all() {
         .collect::<Vec<_>>();
     #[cfg(windows)]
     {
+        expected.retain(|p| p.file_stem().unwrap() == BIN_NAME);
         expected.retain(|p| p.extension().map(|ext| ext == "exe" || ext == "cmd") == Some(true));
     }
     #[cfg(not(windows))]