1 files changed, 32 insertions, 0 deletions
diff --git a/scripts/assert-todos.sh b/scripts/assert-todos.sh
index 7c32524..c3139d1 100755
--- a/scripts/assert-todos.sh
+++ b/scripts/assert-todos.sh
@@ -9,3 +9,35 @@ if grep -R FIXME $(git ls-files) | grep -v '^TODOs.org' | grep -v '^.git/' | gre
   echo "You should write them down properly on TODOs.org."
   exit 1
 fi
+
+contains-element() {
+  local e match="$1"
+  shift
+  for e; do [[ "$e" == "$match" ]] && return 0; done
+  return 1
+}
+
+KNOWN_IDS=()
+has_error=0
+# shellcheck disable=2013
+for todo in $(sed -e '/^\* Tasks$/,/^\* Improvements$/!d' TODOs.org | grep -nE '^\*\* .*$' | cut -d: -f1); do
+  if grep -E '^\*\* (CANCELLED|DONE)' <(sed "${todo}q;d" TODOs.org) > /dev/null; then
+    ID_OFFSET=3
+  else
+    ID_OFFSET=2
+  fi
+  ID="$(sed "$((todo+ID_OFFSET))q;d" TODOs.org)"
+  if grep '^:CUSTOM_ID: .*$' <(echo "$ID") > /dev/null; then
+    if contains-element "$ID" "${KNOWN_IDS[@]}"; then
+      echo "Duplicated ID: $ID"
+      has_error=1
+    else
+      KNOWN_IDS+=("$ID")
+    fi
+  else
+    echo "Missing ID for TODO in line $todo"
+    has_error=1
+  fi
+done
+
+exit "$has_error"