Ensure shebangs properly start with #!

1 files changed, 22 insertions, 1 deletions

diff --git a/src/util/language.rs b/src/util/language.rs
index fae7bf9..8819a1e 100644
--- a/src/util/language.rs
+++ b/src/util/language.rs
@@ -21,7 +21,9 @@ fn detect_from_extension(filename: &Path) -> Option<&'static str> {
 }
 
 fn detect_from_shebang(contents: &str) -> Option<&'static str> {
-    if let Some(first_line) = contents.lines().next() {
+    if let Some(first_line) = contents.lines().next()
+        && first_line.starts_with("#!")
+    {
         if first_line.contains("python") {
             return Some("python");
         }
@@ -31,3 +33,22 @@ fn detect_from_shebang(contents: &str) -> Option<&'static str> {
     }
     None
 }
+
+#[cfg(test)]
+mod tests {
+    use std::path::Path;
+
+    use super::detect_language;
+
+    #[test]
+    fn non_shebang_line_does_not_trigger_detection() {
+        let contents = "this mentions bash but is not a shebang";
+        assert_eq!(detect_language(Path::new("file"), contents), "");
+    }
+
+    #[test]
+    fn detects_python_from_shebang() {
+        let contents = "#!/usr/bin/python3\nprint('hi')";
+        assert_eq!(detect_language(Path::new("file"), contents), "python");
+    }
+}