Look up syntax definitions by full file name when no extension is pre…

…sent

Some syntax definitions apply to files based on their full name (e.g.
"Makefile"). Previously, syntax definition look-ups only used file
extensions when searching for a match. As of this change, the full file
name will be used as a fallback when an extension isn't present.

src/workspace.rs

@@ -435,6 +435,7 @@ impl Workspace {
             .ok_or(ErrorKind::EmptyWorkspace)?;
         let definition = buffer
             .file_extension()
+            .or_else(|| buffer.file_name())
             .and_then(|ex| self.syntax_set.find_syntax_by_extension(&ex))
             .or_else(|| Some(self.syntax_set.find_syntax_plain_text()))
             .cloned();
@@ -493,7 +494,7 @@ mod tests {
     use super::Workspace;
     use crate::buffer::Buffer;
     use std::env;
-    use std::path::Path;
+    use std::path::{Path, PathBuf};
 
     #[test]
     fn add_buffer_adds_and_selects_the_passed_buffer() {
@@ -822,4 +823,46 @@ mod tests {
             "third buffer"
         );
     }
+
+    #[test]
+    fn update_current_syntax_handles_files_without_extensions() {
+        // Create a workspace.
+        let workspace_path = Path::new("tests/sample");
+        let mut workspace = Workspace::new(workspace_path, None).unwrap();
+
+        // Add a buffer without path to the workspace.
+        let buf = Buffer::new();
+        workspace.add_buffer(buf);
+
+        // Ensure a default syntax definition is applied.
+        assert_eq!(
+            workspace
+                .current_buffer
+                .as_ref()
+                .unwrap()
+                .syntax_definition
+                .as_ref()
+                .unwrap()
+                .name,
+            "Plain Text"
+        );
+
+        // Add a path without extension and update the syntax definition.
+        let buffer_path = PathBuf::from("Makefile");
+        workspace.current_buffer.as_mut().unwrap().path = Some(buffer_path);
+        workspace.update_current_syntax().unwrap();
+
+        // Ensure a non-default syntax definition is applied.
+        assert_eq!(
+            workspace
+                .current_buffer
+                .as_ref()
+                .unwrap()
+                .syntax_definition
+                .as_ref()
+                .unwrap()
+                .name,
+            "Makefile"
+        );
+    }
 }