Add bare-resilient GitPath::repo_root (#46)

src/git/path.rs

@@ -2,9 +2,14 @@ use std::fmt::Debug;
 
 use camino::Utf8PathBuf;
 use command_error::CommandExt;
+use command_error::OutputContext;
+use miette::miette;
 use miette::Context;
 use miette::IntoDiagnostic;
 use tracing::instrument;
+use utf8_command::Utf8Output;
+
+use crate::NormalPath;
 
 use super::Git;
 
@@ -23,6 +28,43 @@ impl<'a> GitPath<'a> {
         Self(git)
     }
 
+    /// If in a working tree, get the repository root (`git rev-parse --show-toplevel`). If the
+    /// repository is bare, get the `.git` directory (`git rev-parse --git-dir`). Otherwise, error.
+    #[instrument(level = "trace")]
+    pub fn repo_root_or_git_common_dir_if_bare(&self) -> miette::Result<Utf8PathBuf> {
+        if self.is_inside_work_tree()? {
+            self.repo_root()
+        } else if self.0.config().is_bare()? {
+            self.git_common_dir()
+        } else {
+            Err(miette!(
+                "Path is not in a working tree or a bare repository: {}",
+                NormalPath::try_display_cwd(self.0.get_directory())
+            ))
+        }
+    }
+
+    /// Check if we're inside a working tree.
+    #[instrument(level = "trace")]
+    pub fn is_inside_work_tree(&self) -> miette::Result<bool> {
+        self.0
+            .rev_parse_command()
+            .arg("--is-inside-work-tree")
+            .output_checked_as(|context: OutputContext<Utf8Output>| {
+                if !context.status().success() {
+                    Err(context.error())
+                } else {
+                    let stdout = context.output().stdout.trim();
+                    match stdout {
+                        "true" => Ok(true),
+                        "false" => Ok(false),
+                        _ => Err(context.error_msg("Expected 'true' or 'false'")),
+                    }
+                }
+            })
+            .into_diagnostic()
+    }
+
     /// `git rev-parse --show-toplevel`
     #[instrument(level = "trace")]
     pub fn repo_root(&self) -> miette::Result<Utf8PathBuf> {