A way to parse the first git-config file path (#450)

Author: Byron

Cargo.lock

@@ -110,6 +110,7 @@ git-prompt = { version = "0.1.0", path = "../git-prompt" }
 git-index = { version = "^0.4.3", path = "../git-index" }
 git-worktree = { version = "^0.4.3", path = "../git-worktree" }
 
+once_cell = "1.14.0"
 signal-hook = { version = "0.3.9", default-features = false }
 thiserror = "1.0.26"
 clru = "0.5.0"

git-repository/Cargo.toml

@@ -28,7 +28,21 @@ pub fn os_str_to_bstring(input: &OsStr) -> Result<BString, String> {
 
 /// Environment information involving the `git` program itself.
 pub mod git {
-    use crate::bstr::{BStr, ByteSlice};
+    use crate::bstr::{BStr, BString, ByteSlice};
+    use std::process::{Command, Stdio};
+
+    /// Returns the file that contains git configuration coming with the installation of the `git` file in the current `PATH`, or `None`
+    /// if no `git` executable was found or there were other errors during execution.
+    pub fn install_config_path() -> Option<&'static BStr> {
+        static PATH: once_cell::sync::Lazy<Option<BString>> = once_cell::sync::Lazy::new(|| {
+            let mut cmd = Command::new(if cfg!(windows) { "git.exe" } else { "git" });
+            cmd.args(["config", "-l", "--show-origin"])
+                .stdin(Stdio::null())
+                .stderr(Stdio::null());
+            first_file_from_config_with_origin(cmd.output().ok()?.stdout.as_slice().into()).map(ToOwned::to_owned)
+        });
+        PATH.as_ref().map(|b| b.as_ref())
+    }
 
     fn first_file_from_config_with_origin(source: &BStr) -> Option<&BStr> {
         let file = source.strip_prefix(b"file:")?;