Rollup merge of #92208 - ChrisDenton:win-bat-cmd, r=dtolnay

Quote bat script command line

Fixes #91991

[`CreateProcessW`](https://docs.microsoft.com/en-us/windows/win32/api/processthreadsapi/nf-processthreadsapi-createprocessw#parameters) should only be used to run exe files but it does have some (undocumented) special handling for files with `.bat` and `.cmd` extensions. Essentially those magic extensions will cause the parameters to be automatically rewritten. Example pseudo Rust code (note that `CreateProcess` starts with an optional application name followed by the application arguments):
```rust
// These arguments...
CreateProcess(None, `@"foo.bat` "hello world""`@,` ...);
// ...are rewritten as
CreateProcess(Some(r"C:\Windows\System32\cmd.exe"), `@""foo.bat` "hello world"""`@,` ...);
```

However, when setting the first parameter (the application name) as we now do, it will omit the extra level of quotes around the arguments:

```rust
// These arguments...
CreateProcess(Some("foo.bat"), `@"foo.bat` "hello world""`@,` ...);
// ...are rewritten as
CreateProcess(Some(r"C:\Windows\System32\cmd.exe"), `@"foo.bat` "hello world""`@,` ...);
```

This means the arguments won't be passed to the script as intended.

Note that running batch files this way is undocumented but people have relied on this so we probably shouldn't break it.

2 files changed, 35 insertions, 0 deletions

diff --git a/library/std/src/process/tests.rs b/library/std/src/process/tests.rs
index 61ab0eb55e6..e5cdc473706 100644
--- a/library/std/src/process/tests.rs
+++ b/library/std/src/process/tests.rs
@@ -420,3 +420,22 @@ fn env_empty() {
     let p = Command::new("cmd").args(&["/C", "exit 0"]).env_clear().spawn();
     assert!(p.is_ok());
 }
+
+// See issue #91991
+#[test]
+#[cfg(windows)]
+fn run_bat_script() {
+    let tempdir = crate::sys_common::io::test::tmpdir();
+    let script_path = tempdir.join("hello.cmd");
+
+    crate::fs::write(&script_path, "@echo Hello, %~1!").unwrap();
+    let output = Command::new(&script_path)
+        .arg("fellow Rustaceans")
+        .stdout(crate::process::Stdio::piped())
+        .spawn()
+        .unwrap()
+        .wait_with_output()
+        .unwrap();
+    assert!(output.status.success());
+    assert_eq!(String::from_utf8_lossy(&output.stdout).trim(), "Hello, fellow Rustaceans!");
+}
diff --git a/library/std/src/sys/windows/process.rs b/library/std/src/sys/windows/process.rs
index 66b210ce1bf..e84dfbce4a7 100644
--- a/library/std/src/sys/windows/process.rs
+++ b/library/std/src/sys/windows/process.rs
@@ -704,6 +704,19 @@ fn make_command_line(prog: &OsStr, args: &[Arg], force_quotes: bool) -> io::Resu
     // Encode the command and arguments in a command line string such
     // that the spawned process may recover them using CommandLineToArgvW.
     let mut cmd: Vec<u16> = Vec::new();
+
+    // CreateFileW has special handling for .bat and .cmd files, which means we
+    // need to add an extra pair of quotes surrounding the whole command line
+    // so they are properly passed on to the script.
+    // See issue #91991.
+    let is_batch_file = Path::new(prog)
+        .extension()
+        .map(|ext| ext.eq_ignore_ascii_case("cmd") || ext.eq_ignore_ascii_case("bat"))
+        .unwrap_or(false);
+    if is_batch_file {
+        cmd.push(b'"' as u16);
+    }
+
     // Always quote the program name so CreateProcess doesn't interpret args as
     // part of the name if the binary wasn't found first time.
     append_arg(&mut cmd, prog, Quote::Always)?;
@@ -715,6 +728,9 @@ fn make_command_line(prog: &OsStr, args: &[Arg], force_quotes: bool) -> io::Resu
         };
         append_arg(&mut cmd, arg, quote)?;
     }
+    if is_batch_file {
+        cmd.push(b'"' as u16);
+    }
     return Ok(cmd);
 
     fn append_arg(cmd: &mut Vec<u16>, arg: &OsStr, quote: Quote) -> io::Result<()> {