fix: detect logged-in user's home directory when running as root

When asimov runs as root (via brew services or sudo), ~ expands to
/var/root. Now detects the console user via stat/dscl and uses their
home directory instead.

Addresses stevegrunwell#72.

Author: django23

CHANGELOG.md

@@ -38,6 +38,7 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 ### Fixed
 
 * Handle `tmutil` errors gracefully instead of crashing; paths that fail exclusion are skipped with a warning ([stevegrunwell/asimov#101], [stevegrunwell/asimov#86])
+* Detect the logged-in user's home directory when running as root, fixing `brew services` and `sudo` invocations that would search `/var/root` instead ([stevegrunwell/asimov#72])
 
 ### Changed
 
@@ -134,6 +135,7 @@ Initial public release.
 [#56]: https://github.com/stevegrunwell/asimov/pull/56
 [stevegrunwell/asimov#64]: https://github.com/stevegrunwell/asimov/pull/64
 [stevegrunwell/asimov#69]: https://github.com/stevegrunwell/asimov/pull/69
+[stevegrunwell/asimov#72]: https://github.com/stevegrunwell/asimov/issues/72
 [stevegrunwell/asimov#84]: https://github.com/stevegrunwell/asimov/issues/84
 [stevegrunwell/asimov#86]: https://github.com/stevegrunwell/asimov/issues/86
 [stevegrunwell/asimov#87]: https://github.com/stevegrunwell/asimov/pull/87

asimov

@@ -21,7 +21,19 @@ trap 'rm -f "$ASIMOV_SIZE_LOG"' EXIT
 # @author  Steve Grunwell
 # @license MIT
 
-readonly ASIMOV_ROOT=~
+# When running as root (e.g. via launchd or sudo), determine the logged-in
+# user's home directory instead of using /var/root.
+if [[ "${EUID:-$(id -u)}" -eq 0 ]]; then
+    _console_user="$(stat -f '%Su' /dev/console 2>/dev/null || echo '')"
+    if [[ -n "$_console_user" && "$_console_user" != "root" ]]; then
+        _root_dir="$(dscl . -read "/Users/${_console_user}" NFSHomeDirectory 2>/dev/null | awk '{print $2}')"
+        readonly ASIMOV_ROOT="$_root_dir"
+    else
+        readonly ASIMOV_ROOT=~
+    fi
+else
+    readonly ASIMOV_ROOT=~
+fi
 
 # Paths to unconditionally skip over. This prevents Asimov from modifying the
 # Time Machine exclusions for these paths (and descendants). It has an important

tests/behavior.bats

@@ -131,6 +131,17 @@ load test_helper
   [[ "$(count_exclusions)" -eq 1 ]]
 }
 
+# =============================================================================
+# ASIMOV_ROOT detection
+# =============================================================================
+
+@test "uses HOME as root directory when not running as root" {
+  create_project "Code/My-Project" "package.json" "node_modules"
+  run_asimov
+  assert_excluded "${HOME}/Code/My-Project/node_modules"
+  [[ "$(count_exclusions)" -eq 1 ]]
+}
+
 @test "does not descend into excluded dependency directories" {
   # A node_modules inside another node_modules should not be separately excluded
   create_project "Code/My-Project" "package.json" "node_modules"