fix: handle tmutil errors gracefully instead of crashing

When tmutil addexclusion fails (e.g. Error -20 or -50 on paths inside
app bundles or with permission issues), skip the path with a warning
instead of crashing. This allows asimov to continue processing
remaining directories.

Addresses stevegrunwell#101 and stevegrunwell#86.

Author: django23

CHANGELOG.md

@@ -34,6 +34,10 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 * Added `scripts/uninstall.sh` to cleanly remove Asimov and its launchd schedule ([#35], props @sylver)
 * Added common interval reference comments to `com.stevegrunwell.asimov.plist` ([#35], props @sylver)
 
+### Fixed
+
+* Handle `tmutil` errors gracefully instead of crashing; paths that fail exclusion are skipped with a warning ([stevegrunwell/asimov#101], [stevegrunwell/asimov#86])
+
 ### Changed
 
 * Skip directories already excluded from Time Machine backups for faster subsequent runs (inspired by [stevegrunwell/asimov#97], props @VladRassokhin)
@@ -129,5 +133,7 @@ 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#86]: https://github.com/stevegrunwell/asimov/issues/86
 [stevegrunwell/asimov#87]: https://github.com/stevegrunwell/asimov/pull/87
 [stevegrunwell/asimov#97]: https://github.com/stevegrunwell/asimov/pull/97
+[stevegrunwell/asimov#101]: https://github.com/stevegrunwell/asimov/issues/101

asimov

@@ -122,7 +122,10 @@ exclude_file() {
             continue
         fi
 
-        tmutil addexclusion "${path}"
+        if ! tmutil addexclusion "${path}" 2>/dev/null; then
+            echo "! ${path}: failed to exclude (tmutil error), skipping." >&2
+            continue
+        fi
 
         sizeondisk=$(du -hs "${path}" | cut -f1)
         echo "- ${path} has been excluded from Time Machine backups (${sizeondisk})."

tests/behavior.bats

@@ -207,3 +207,41 @@ load test_helper
   second_count="$(count_exclusions)"
   [[ "$second_count" -eq 1 ]]
 }
+
+# =============================================================================
+# Error handling
+# =============================================================================
+
+@test "continues when tmutil fails for a path" {
+  create_project "Code/Good-Project" "package.json" "node_modules"
+  create_project "Code/Bad-Project" "Cargo.toml" "target"
+
+  # Mark the bad project as one that will cause tmutil to fail
+  ASIMOV_TEST_TMUTIL_FAIL_PATHS="${TEST_TEMP_DIR}/.tmutil_fail_paths"
+  export ASIMOV_TEST_TMUTIL_FAIL_PATHS
+  echo "${HOME}/Code/Bad-Project/target" > "$ASIMOV_TEST_TMUTIL_FAIL_PATHS"
+
+  run_asimov
+
+  # The good project should still be excluded
+  assert_excluded "${HOME}/Code/Good-Project/node_modules"
+  # The bad project should NOT be in the exclusions list
+  refute_excluded "${HOME}/Code/Bad-Project/target"
+  [[ "$(count_exclusions)" -eq 1 ]]
+}
+
+@test "prints warning when tmutil fails" {
+  create_project "Code/Bad-Project" "package.json" "node_modules"
+
+  ASIMOV_TEST_TMUTIL_FAIL_PATHS="${TEST_TEMP_DIR}/.tmutil_fail_paths"
+  export ASIMOV_TEST_TMUTIL_FAIL_PATHS
+  echo "${HOME}/Code/Bad-Project/node_modules" > "$ASIMOV_TEST_TMUTIL_FAIL_PATHS"
+
+  run_asimov
+
+  # Script should succeed (exit 0) even though tmutil failed
+  [[ "$status" -eq 0 ]]
+  # Output should contain the warning
+  [[ "$output" == *"failed to exclude"* ]]
+  [[ "$(count_exclusions)" -eq 0 ]]
+}

tests/bin/tmutil

@@ -24,6 +24,13 @@ case "$subcommand" in
     fi
     ;;
   addexclusion)
+    # Simulate failure for paths listed in ASIMOV_TEST_TMUTIL_FAIL_PATHS
+    if [[ -n "${ASIMOV_TEST_TMUTIL_FAIL_PATHS:-}" && -f "${ASIMOV_TEST_TMUTIL_FAIL_PATHS}" ]]; then
+      if grep -Fxq "$path" "$ASIMOV_TEST_TMUTIL_FAIL_PATHS" 2>/dev/null; then
+        echo "Error (-50) while attempting to change exclusion setting." >&2
+        exit 1
+      fi
+    fi
     printf '%s\n' "$path" >> "$ASIMOV_TEST_EXCLUSIONS"
     ;;
   *)