Add shebang support for 'cmd.exe' (#828)

src/recipe.rs

@@ -127,8 +127,9 @@ impl<'src, D> Recipe<'src, D> {
           io_error: error,
         })?;
       let mut path = tmp.path().to_path_buf();
-      let suffix = if interpreter.ends_with("powershell") || interpreter.ends_with("powershell.exe")
-      {
+      let suffix = if interpreter.ends_with("cmd") || interpreter.ends_with("cmd.exe") {
+        ".bat"
+      } else if interpreter.ends_with("powershell") || interpreter.ends_with("powershell.exe") {
         ".ps1"
       } else {
         ""
@@ -141,7 +142,11 @@ impl<'src, D> Recipe<'src, D> {
         })?;
         let mut text = String::new();
         // add the shebang
-        text += &evaluated_lines[0];
+        if interpreter.ends_with("cmd") || interpreter.ends_with("cmd.exe") {
+          text += "\n";
+        } else {
+          text += &evaluated_lines[0];
+        }
         text += "\n";
         // add blank lines so that lines in the generated script have the same line
         // number as the corresponding lines in the justfile

tests/shebang.rs

@@ -19,3 +19,25 @@ default:
 "#,
   stdout: "Hello-World\n",
 }
+
+#[cfg(windows)]
+test! {
+  name:     cmd,
+  justfile: r#"
+default:
+  #!cmd /c
+  @echo Hello-World
+"#,
+  stdout: "Hello-World\r\n",
+}
+
+#[cfg(windows)]
+test! {
+  name:     cmd_exe,
+  justfile: r#"
+default:
+  #!cmd.exe /c
+  @echo Hello-World
+"#,
+  stdout: "Hello-World\r\n",
+}