Fix 3 confirmed bugs: stale PID files, accumulated error logs, and silent mysqldump failures

BUG 1: mysql.pid file not cleaned up after process dies
- Location: cleanup_on_exit() function
- Impact: Stale PID files accumulate in TEMP_DATADIR over repeated runs
- Fix: Added rm -f of mysql.pid in cleanup_on_exit()
- Result: PID files now properly cleaned up on exit

BUG 2: mysql.err.old error log backups accumulate
- Location: cleanup_on_exit() function
- Impact: Error log backups accumulate over time, wasting disk space
- Fix: Added rm -f of mysql.err.old in cleanup_on_exit()
- Result: Error log backups no longer pile up

BUG 3: mysqldump errors silently ignored with 2>/dev/null
- Location: dump_database() function, line 1292
- Impact: If mysqldump fails, user sees no error message
- Problem: stderr redirected to /dev/null, errors lost
- Fix: Capture stderr to temp file, show errors if mysqldump fails
- Result: Users now see mysqldump errors with details
- Improvement: Clear error message with exit code + error details

Testing these fixes:
1. Run script multiple times - no mysql.pid accumulation
2. Check TEMP_DATADIR - no mysql.err.old files after cleanup
3. Force mysqldump failure (e.g., invalid socket) - see error message

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

modules/backup/mysql-restore-to-sql.sh

@@ -83,6 +83,12 @@ cleanup_on_exit() {
                 rm -f "$TEMP_DATADIR/socket.mysql" "$TEMP_DATADIR/mysql.lock" 2>/dev/null || true
             fi
 
+            # Clean up PID file if it still exists (BUG FIX: stale PID cleanup)
+            rm -f "$TEMP_DATADIR/mysql.pid" 2>/dev/null || true
+
+            # Clean up error log backups to prevent accumulation (BUG FIX: mysql.err.old cleanup)
+            rm -f "$TEMP_DATADIR/mysql.err.old" 2>/dev/null || true
+
             print_success "Second instance cleaned up"
         fi
     fi
@@ -1281,7 +1287,10 @@ dump_database() {
 
     # Perform dump
     echo ""
-    if mysqldump -h localhost -S "$datadir/socket.mysql" --single-transaction "$dbname" > "$output_file" 2>/dev/null; then
+    # BUG FIX: Capture mysqldump stderr to show errors if dump fails
+    local dump_stderr=$(mktemp)
+    if mysqldump -h localhost -S "$datadir/socket.mysql" --single-transaction "$dbname" > "$output_file" 2>"$dump_stderr"; then
+        rm -f "$dump_stderr"
         # Verify dump completed
         if grep -q "Dump completed on" "$output_file"; then
             local size=$(du -h "$output_file" | awk '{print $1}')
@@ -1305,7 +1314,15 @@ dump_database() {
             return 1
         fi
     else
-        print_error "mysqldump failed"
+        # BUG FIX: Show mysqldump errors instead of silently failing
+        print_error "mysqldump failed with exit code $?"
+        if [ -f "$dump_stderr" ] && [ -s "$dump_stderr" ]; then
+            print_error "Error details:"
+            while IFS= read -r line; do
+                echo "  $line" | sed 's/^[[:space:]]*/  /'
+            done < "$dump_stderr"
+            rm -f "$dump_stderr"
+        fi
         return 1
     fi
 }