Only use cygpath on shebang if it contains / (#652)

On Windows, skip conversion if a shebang path does not include `/`. In
this case it is not a Unix path, and does not need to be converted to a
Windows path before running.

.github/workflows/build.yaml

@@ -5,7 +5,7 @@ on:
     branches:
     - master
     tags:
-    - v*.*.*
+    - '*'
   pull_request:
     branches:
     - master
@@ -30,9 +30,12 @@ jobs:
 
     runs-on: ${{matrix.os}}
 
+    env:
+      RUSTFLAGS: "-D warnings"
+
     steps:
 
-    - uses: actions/checkout@v1
+    - uses: actions/checkout@v2
 
     - name: Cache cargo registry
       uses: actions/cache@v1
@@ -99,16 +102,16 @@ jobs:
 
     - name: Package
       id: package
-      if: startsWith(github.ref, 'refs/tags/v')
+      if: startsWith(github.ref, 'refs/tags/')
       run: ./bin/package ${{github.ref}} ${{matrix.os}} ${{ matrix.target }}
       shell: bash
 
     - name: Publish
       uses: softprops/action-gh-release@v1
-      if: startsWith(github.ref, 'refs/tags/v')
+      if: startsWith(github.ref, 'refs/tags/')
       with:
         draft: false
         files: ${{ steps.package.outputs.archive }}
-        prerelease: false
+        prerelease: true
       env:
         GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

README.adoc

@@ -694,6 +694,25 @@ Yo from a shell script!
 Hello from ruby!
 ```
 
+==== Shebang Recipe Execution on Windows
+
+On Windows, shebang interpreter paths containing a `/` are translated from Unix-style
+paths to Windows-style paths using `cygpath`, a utility that ships with http://www.cygwin.com[Cygwin].
+
+For example, to execute this recipe on Windows:
+
+```make
+echo:
+  #!/bin/sh
+
+  echo "Hello!"
+```
+
+The interpreter path `/bin/sh` will be translated to a Windows-style path using
+`cygpath` before being executed.
+
+If the interpreter path does not contain a `/` it will be executed without being translated. This is useful if `cygpath` is not available, or you wish to use a Windows style path to the interpreter.
+
 === Multi-line Constructs
 
 Recipes without an initial shebang are evaluated and run line-by-line, which means that multi-line constructs probably won't do what you want.

src/platform.rs

@@ -53,19 +53,28 @@ impl PlatformInterface for Platform {
     command: &str,
     argument: Option<&str>,
   ) -> Result<Command, OutputError> {
-    // Translate path to the interpreter from unix style to windows style
+    // If the path contains forward slashes…
+    let command = if command.contains('/') {
+      // …translate path to the interpreter from unix style to windows style.
       let mut cygpath = Command::new("cygpath");
       cygpath.current_dir(working_directory);
       cygpath.arg("--windows");
       cygpath.arg(command);
 
-    let mut cmd = Command::new(output(cygpath)?);
+      Cow::Owned(output(cygpath)?)
+    } else {
+      // …otherwise use it as-is.
+      Cow::Borrowed(command)
+    };
+
+    let mut cmd = Command::new(command.as_ref());
 
     cmd.current_dir(working_directory);
 
     if let Some(argument) = argument {
       cmd.arg(argument);
     }
+
     cmd.arg(path);
     Ok(cmd)
   }

tests/integration.rs

@@ -2635,3 +2635,15 @@ test! {
   status: 127,
   shell: false,
 }
+
+#[cfg(windows)]
+test! {
+  name: windows_interpreter_path_no_base,
+  justfile: r#"
+    foo:
+      #!powershell
+
+      exit 0
+  "#,
+  args: (),
+}