chore(i18n): add checker for t shadowing in svelte files

cx

package.json

@@ -10,6 +10,7 @@
     "preview": "vite preview",
     "check": "svelte-kit sync && svelte-check --tsconfig ./tsconfig.json",
     "check:watch": "svelte-kit sync && svelte-check --tsconfig ./tsconfig.json --watch",
+    "check:no-t-shadow": "bash ./scripts/check-no-t-shadow.sh",
     "test": "vitest",
     "test:run": "vitest run",
     "tauri": "tauri"

scripts/check-no-t-shadow.sh

@@ -0,0 +1,44 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+SRC_DIR="${ROOT_DIR}/src"
+
+echo "Checking for forbidden i18n 't' shadowing patterns in .svelte files..."
+
+had_issues=0
+
+check_pattern() {
+  local label="$1"
+  local pattern="$2"
+  if rg -n --glob '*.svelte' "${pattern}" "${SRC_DIR}" >/tmp/qbz_t_shadow_check.out 2>/dev/null; then
+    echo
+    echo "Found ${label}:"
+    cat /tmp/qbz_t_shadow_check.out
+    had_issues=1
+  fi
+}
+
+# Template loop variable shadowing.
+check_pattern "template each-loop shadowing (as t)" '\{#each[^\n]* as t\b'
+
+# Dangerous callbacks in files using $t(...).
+while IFS= read -r file; do
+  if rg -q '\b(map|forEach|filter|find|some|every|reduce)\(\s*t\s*=>' "${file}"; then
+    echo
+    echo "Found callback shadowing in file using \$t(...): ${file}"
+    rg -n '\b(map|forEach|filter|find|some|every|reduce)\(\s*t\s*=>' "${file}"
+    had_issues=1
+  fi
+done < <(rg -l --glob '*.svelte' '\$t\(' "${SRC_DIR}")
+
+# Any $derived expression using variable name t.
+check_pattern "usage of t inside \$derived" '\$derived\([^)]*\bt\b'
+
+if [[ "${had_issues}" -ne 0 ]]; then
+  echo
+  echo "check-no-t-shadow: FAIL"
+  exit 1
+fi
+
+echo "check-no-t-shadow: OK"