Refactor for readability; clarify comments

Author: EliahKagan

gix-path/src/env/git/mod.rs

@@ -109,23 +109,21 @@ fn exe_info() -> Option<BString> {
 fn git_cmd(executable: PathBuf) -> Command {
     let mut cmd = Command::new(executable);
 
-    #[cfg(windows)]
-    {
-        use std::env;
+    if cfg!(windows) {
         use std::os::windows::process::CommandExt;
         const CREATE_NO_WINDOW: u32 = 0x08000000;
         cmd.creation_flags(CREATE_NO_WINDOW);
 
-        cmd.current_dir(
-            env::var_os("SystemRoot") // Most reliable env var for path to Windows directory.
-                .or_else(|| env::var_os("windir")) // Less reliable, but some callers are unusual.
-                .map(PathBuf::from)
-                .filter(|p| p.is_absolute())
-                .unwrap_or_else(env::temp_dir),
-        );
+        use std::env;
+        let cwd = env::var_os("SystemRoot") // Usually `C:\Windows`. Not to be confused with `C:\`.
+            .or_else(|| env::var_os("windir")) // Same. Less reliable, but some callers are unusual.
+            .map(PathBuf::from)
+            .filter(|p| p.is_absolute())
+            .unwrap_or_else(env::temp_dir);
+        cmd.current_dir(cwd);
+    } else {
+        cmd.current_dir("/");
     }
-    #[cfg(not(windows))]
-    cmd.current_dir("/");
 
     // Git 2.8.0 and higher support --show-origin. The -l, -z, and --name-only options were
     // supported even before that. In contrast, --show-scope was introduced later, in Git 2.26.0.
@@ -140,7 +138,7 @@ fn git_cmd(executable: PathBuf) -> Command {
     //
     cmd.args(["config", "-lz", "--show-origin", "--name-only"])
         .env("GIT_DIR", NULL_DEVICE) // Avoid getting local-scope config.
-        .env("GIT_WORK_TREE", NULL_DEVICE) // Not needed, but clarifies intent.
+        .env("GIT_WORK_TREE", NULL_DEVICE) // Just to avoid confusion when debugging.
         .stdin(Stdio::null())
         .stderr(Stdio::null());
 

gix-path/src/env/git/tests.rs

@@ -360,7 +360,7 @@ use std::path::{Path, PathBuf};
 use gix_testtools::tempfile;
 use serial_test::serial;
 
-/// Wrapper for a path to a location kept from accidentally existing, until drop.
+/// Wrapper for a valid path to a plausible location, kept from accidentally existing (until drop).
 #[derive(Debug)]
 struct NonexistentLocation {
     _empty: tempfile::TempDir,
@@ -443,8 +443,8 @@ fn exe_info_tolerates_broken_temp() {
 #[test]
 #[serial]
 fn exe_info_tolerates_oversanitized_env() {
-    // This test runs on all systems, but it is a regression test for Windows.
-    // Also, having both a broken temp dir and an over-sanitized environment is not supported.
+    // This test runs on all systems, but it is only checking for a Windows regression. Also, on
+    // Windows, having both a broken temp dir and an over-sanitized environment is not supported.
     let _env = unset_windows_directory_vars();
     check_exe_info();
 }
@@ -466,7 +466,6 @@ fn exe_info_same_result_with_broken_temp() {
 #[test]
 #[serial]
 fn exe_info_same_result_with_oversanitized_env() {
-    // See `exe_info_tolerates_oversanitized_env`.
     let with_unmodified_env = super::exe_info();
 
     let with_oversanitized_env = {