Silence bogus GCC 7 warnings -Wimplicit-fallthrough

Do not silence uncertain cases, or fix any bugs.

The only functional change should be that ha_federated::extra()
is not calling DBUG_PRINT to report an unhandled case for
HA_EXTRA_PREPARE_FOR_DROP.

client/mysqldump.c

@@ -2168,6 +2168,7 @@ static void print_xml_comment(FILE *xml_file, size_t len,
     case '-':
       if (*(comment_string + 1) == '-')         /* Only one hyphen allowed. */
         break;
+      /* fall through */
     default:
       fputc(*comment_string, xml_file);
       break;

extra/replace.c

@@ -174,6 +174,7 @@ register char **argv[];
 	break;
       case 'V':
 	version=1;
+	/* fall through */
       case 'I':
       case '?':
 	help=1;					/* Help text written */

sql/events.cc

@@ -1,5 +1,6 @@
 /*
    Copyright (c) 2005, 2013, Oracle and/or its affiliates.
+   Copyright (c) 2017, MariaDB Corporation.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -242,6 +243,7 @@ Events::reconstruct_interval_expression(String *buf, interval_type interval,
     break;
   case INTERVAL_WEEK:
     expr/= 7;
+    /* fall through */
   default:
     close_quote= FALSE;
     break;

sql/field.cc

@@ -10126,7 +10126,7 @@ bool Create_field::check(THD *thd)
   case MYSQL_TYPE_DATE:
     /* We don't support creation of MYSQL_TYPE_DATE anymore */
     sql_type= MYSQL_TYPE_NEWDATE;
-    /* fall trough */
+    /* fall through */
   case MYSQL_TYPE_NEWDATE:
     length= MAX_DATE_WIDTH;
     break;

sql/item.cc

@@ -1,6 +1,6 @@
 /*
    Copyright (c) 2000, 2016, Oracle and/or its affiliates.
-   Copyright (c) 2010, 2016, MariaDB
+   Copyright (c) 2010, 2017, MariaDB
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -5824,7 +5824,7 @@ Field *Item::tmp_table_field_from_field_type(TABLE *table,
         Field_string(max_length, maybe_null, name, collation.collation);
       break;
     }
-    /* Fall through to make_string_field() */
+    /* Fall through */
   case MYSQL_TYPE_ENUM:
   case MYSQL_TYPE_SET:
   case MYSQL_TYPE_VAR_STRING:

sql/item_func.cc

@@ -1,5 +1,5 @@
 /* Copyright (c) 2000, 2015, Oracle and/or its affiliates.
-   Copyright (c) 2009, 2015, MariaDB
+   Copyright (c) 2009, 2017, MariaDB
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -1944,6 +1944,7 @@ my_decimal *Item_func_mod::decimal_op(my_decimal *decimal_value)
     return decimal_value;
   case E_DEC_DIV_ZERO:
     signal_divide_by_null();
+    /* fall through */
   default:
     null_value= 1;
     return 0;

sql/item_strfunc.cc

@@ -226,7 +226,7 @@ String *Item_func_sha2::val_str_ascii(String *str)
     break;
   case 0: // SHA-256 is the default
     digest_length= 256;
-    /* fall trough */
+    /* fall through */
   case 256:
     my_sha256(digest_buf, input_ptr, input_len);
     break;
@@ -272,7 +272,7 @@ void Item_func_sha2::fix_length_and_dec()
   switch (sha_variant) {
   case 0: // SHA-256 is the default
     sha_variant= 256;
-    /* fall trough */
+    /* fall through */
   case 512:
   case 384:
   case 256:
@@ -5060,7 +5060,7 @@ bool Item_dyncol_get::get_date(MYSQL_TIME *ltime, ulonglong fuzzy_date)
     goto null;
   case DYN_COL_INT:
     signed_value= 1;                                  // For error message
-    /* fall_trough */
+    /* fall through */
   case DYN_COL_UINT:
     if (signed_value || val.x.ulong_value <= LONGLONG_MAX)
     {
@@ -5073,7 +5073,7 @@ bool Item_dyncol_get::get_date(MYSQL_TIME *ltime, ulonglong fuzzy_date)
     }
     /* let double_to_datetime_with_warn() issue the warning message */
     val.x.double_value= static_cast<double>(ULONGLONG_MAX);
-    /* fall_trough */
+    /* fall through */
   case DYN_COL_DOUBLE:
     if (double_to_datetime_with_warn(val.x.double_value, ltime, fuzzy_date,
                                      0 /* TODO */))

sql/log.cc

@@ -1,5 +1,5 @@
 /* Copyright (c) 2000, 2016, Oracle and/or its affiliates.
-   Copyright (c) 2009, 2016, MariaDB
+   Copyright (c) 2009, 2017, MariaDB
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -9186,8 +9186,10 @@ void TC_LOG_MMAP::close()
     mysql_cond_destroy(&COND_pool);
     mysql_cond_destroy(&COND_active);
     mysql_cond_destroy(&COND_queue_busy);
+    /* fall through */
   case 5:
     data[0]='A'; // garble the first (signature) byte, in case mysql_file_delete fails
+    /* fall through */
   case 4:
     for (i=0; i < npages; i++)
     {
@@ -9196,10 +9198,13 @@ void TC_LOG_MMAP::close()
       mysql_mutex_destroy(&pages[i].lock);
       mysql_cond_destroy(&pages[i].cond);
     }
+    /* fall through */
   case 3:
     my_free(pages);
+    /* fall through */
   case 2:
     my_munmap((char*)data, (size_t)file_length);
+    /* fall through */
   case 1:
     mysql_file_close(fd, MYF(0));
   }

sql/mysqld.cc

@@ -9269,6 +9269,9 @@ mysql_getopt_value(const char *name, uint length,
       return (uchar**) &key_cache->changed_blocks_hash_size;
     }
   }
+  /* We return in all cases above. Let us silence -Wimplicit-fallthrough */
+  DBUG_ASSERT(0);
+  /* fall through */
 #ifdef HAVE_REPLICATION
   case OPT_REPLICATE_DO_DB:
   case OPT_REPLICATE_DO_TABLE:

sql/opt_sum.cc

@@ -1,5 +1,5 @@
 /* Copyright (c) 2000, 2011, Oracle and/or its affiliates.
-   Copyright (c) 2008-2011 Monty Program Ab
+   Copyright (c) 2008, 2017, MariaDB Corporation.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -1042,6 +1042,7 @@ static int maxmin_in_range(bool max_fl, Field* field, COND *cond)
   case Item_func::LT_FUNC:
   case Item_func::LE_FUNC:
     less_fl= 1;
+    /* fall through */
   case Item_func::GT_FUNC:
   case Item_func::GE_FUNC:
   {

sql/rpl_gtid.cc

@@ -2046,7 +2046,7 @@ gtid_waiting::wait_for_pos(THD *thd, String *gtid_str, longlong timeout_us)
   {
     case -1:
       status_var_increment(thd->status_var.master_gtid_wait_timeouts);
-      /* Deliberate fall through. */
+      /* fall through */
     case 0:
       status_var_add(thd->status_var.master_gtid_wait_time,
                      microsecond_interval_timer() - before);

sql/slave.cc

@@ -1,5 +1,5 @@
 /* Copyright (c) 2000, 2016, Oracle and/or its affiliates.
-   Copyright (c) 2009, 2016, MariaDB
+   Copyright (c) 2009, 2017, MariaDB
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -6072,9 +6072,8 @@ static int queue_event(Master_info* mi,const char* buf, ulong event_len)
           mi->last_queued_gtid.seq_no == 1000)
         goto skip_relay_logging;
     });
-    /* Fall through to default case ... */
 #endif
-
+    /* fall through */
   default:
   default_action:
     DBUG_EXECUTE_IF("kill_slave_io_after_2_events",

sql/sp_head.cc

@@ -1,6 +1,6 @@
 /*
    Copyright (c) 2002, 2016, Oracle and/or its affiliates.
-   Copyright (c) 2011, 2016, MariaDB
+   Copyright (c) 2011, 2017, MariaDB
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -142,6 +142,7 @@ sp_get_item_value(THD *thd, Item *item, String *str)
     if (item->field_type() != MYSQL_TYPE_BIT)
       return item->val_str(str);
     else {/* Bit type is handled as binary string */}
+    /* fall through */
   case STRING_RESULT:
     {
       String *result= item->val_str(str);

sql/sql_class.cc

@@ -5532,6 +5532,7 @@ bool xid_cache_insert(THD *thd, XID_STATE *xid_state)
     break;
   case 1:
     my_error(ER_XAER_DUPID, MYF(0));
+    /* fall through */
   default:
     xid_state->xid_cache_element= 0;
   }

sql/sql_digest.cc

@@ -1,4 +1,5 @@
 /* Copyright (c) 2008, 2015, Oracle and/or its affiliates. All rights reserved.
+   Copyright (c) 2017, MariaDB Corporation.
 
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -454,7 +455,8 @@ sql_digest_state* digest_add_token(sql_digest_state *state,
         }
       } while (found_unary);
     }
-    /* fall through, for case NULL_SYM below */
+    /* for case NULL_SYM below */
+    /* fall through */
     case LEX_HOSTNAME:
     case TEXT_STRING:
     case NCHAR_STRING:

sql/sql_lex.cc

@@ -1,5 +1,5 @@
 /* Copyright (c) 2000, 2014, Oracle and/or its affiliates.
-   Copyright (c) 2009, 2016, MariaDB
+   Copyright (c) 2009, 2017, MariaDB
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -1395,12 +1395,14 @@ static int lex_one_token(YYSTYPE *yylval, THD *thd)
 	state= MY_LEX_HEX_NUMBER;
 	break;
       }
+      /* fall through */
     case MY_LEX_IDENT_OR_BIN:
       if (lip->yyPeek() == '\'')
       {                                 // Found b'bin-number'
         state= MY_LEX_BIN_NUMBER;
         break;
       }
+      /* fall through */
     case MY_LEX_IDENT:
       const char *start;
 #if defined(USE_MB) && defined(USE_MB_IDENT)
@@ -1745,6 +1747,7 @@ static int lex_one_token(YYSTYPE *yylval, THD *thd)
 	break;
       }
       /* " used for strings */
+      /* fall through */
     case MY_LEX_STRING:			// Incomplete text string
     {
       uint sep;

sql/sql_parse.cc

@@ -2932,8 +2932,8 @@ mysql_execute_command(THD *thd)
 		 MYF(0));
       goto error;
     }
-    /* no break; fall through */
   }
+    /* fall through */
   case SQLCOM_SHOW_STATUS_PROC:
   case SQLCOM_SHOW_STATUS_FUNC:
   case SQLCOM_SHOW_DATABASES:
@@ -2947,7 +2947,7 @@ mysql_execute_command(THD *thd)
   case SQLCOM_SELECT:
     if (WSREP_CLIENT(thd) && wsrep_sync_wait(thd))
       goto error;
-
+    /* fall through */
   case SQLCOM_SHOW_PLUGINS:
   case SQLCOM_SHOW_VARIABLES:
   case SQLCOM_SHOW_CHARSETS:
@@ -3776,8 +3776,8 @@ mysql_execute_command(THD *thd)
     /* mysql_update return 2 if we need to switch to multi-update */
     if (up_result != 2)
       break;
-    /* Fall through */
   }
+    /* Fall through */
   case SQLCOM_UPDATE_MULTI:
   {
     DBUG_ASSERT(first_table == all_tables && first_table != 0);
@@ -3895,6 +3895,7 @@ mysql_execute_command(THD *thd)
     }
 #endif
   }
+  /* fall through */
   case SQLCOM_INSERT:
   {
     DBUG_ASSERT(first_table == all_tables && first_table != 0);
@@ -4809,6 +4810,7 @@ mysql_execute_command(THD *thd)
       initialize this variable because RESET shares the same code as FLUSH
     */
     lex->no_write_to_binlog= 1;
+    /* fall through */
   case SQLCOM_FLUSH:
   {
     int write_to_binlog;

sql/sql_plugin.cc

@@ -1,6 +1,6 @@
 /*
    Copyright (c) 2005, 2013, Oracle and/or its affiliates.
-   Copyright (c) 2010, 2014, SkySQL Ab.
+   Copyright (c) 2010, 2017, MariaDB Corporation.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -1848,8 +1848,8 @@ static bool plugin_load_list(MEM_ROOT *tmp_root, const char *list)
     switch ((*(p++)= *(list++))) {
     case '\0':
       list= NULL; /* terminate the loop */
-      /* fall through */
 #ifndef __WIN__
+      /* fall through */
     case ':':     /* can't use this as delimiter as it may be drive letter */
 #endif
     case ';':
@@ -1890,6 +1890,7 @@ static bool plugin_load_list(MEM_ROOT *tmp_root, const char *list)
         str->str= p;
         continue;
       }
+      /* fall through */
     default:
       str->length++;
       continue;

sql/sql_prepare.cc

@@ -1,5 +1,5 @@
 /* Copyright (c) 2002, 2015, Oracle and/or its affiliates.
-   Copyright (c) 2008, 2015, MariaDB
+   Copyright (c) 2008, 2017, MariaDB
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -2298,7 +2298,7 @@ static bool check_prepared_statement(Prepared_statement *stmt)
     /* mysql_test_update returns 2 if we need to switch to multi-update */
     if (res != 2)
       break;
-
+    /* fall through */
   case SQLCOM_UPDATE_MULTI:
     res= mysql_test_multiupdate(stmt, tables, res == 2);
     break;

sql/sql_show.cc

@@ -1,5 +1,5 @@
 /* Copyright (c) 2000, 2015, Oracle and/or its affiliates.
-   Copyright (c) 2009, 2016, MariaDB
+   Copyright (c) 2009, 2017, MariaDB
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -1079,6 +1079,7 @@ class Show_create_error_handler : public Internal_error_handler {
         is_handled= FALSE;
         break;
       }
+      /* fall through */
     case ER_COLUMNACCESS_DENIED_ERROR:
     case ER_VIEW_NO_EXPLAIN: /* Error was anonymized, ignore all the same. */
     case ER_PROCACCESS_DENIED_ERROR:

sql/sql_table.cc

@@ -6880,7 +6880,8 @@ bool alter_table_manage_keys(TABLE *table, int indexes_were_disabled,
   case Alter_info::LEAVE_AS_IS:
     if (!indexes_were_disabled)
       break;
-    /* fall-through: disabled indexes */
+    /* disabled indexes */
+    /* fall through */
   case Alter_info::DISABLE:
     error= table->file->ha_disable_indexes(HA_KEY_SWITCH_NONUNIQ_SAVE);
   }

sql/sql_yacc.yy

@@ -4680,9 +4680,11 @@ size_number:
                 case 'g':
                 case 'G':
                   text_shift_number+=10;
+                  /* fall through */
                 case 'm':
                 case 'M':
                   text_shift_number+=10;
+                  /* fall through */
                 case 'k':
                 case 'K':
                   text_shift_number+=10;

sql/wsrep_thd.cc

@@ -382,7 +382,8 @@ static void wsrep_replication_process(THD *thd)
   case WSREP_TRX_MISSING:
     /* these suggests a bug in provider code */
     WSREP_WARN("bad return from recv() call: %d", rcode);
-    /* fall through to node shutdown */
+    /* Shut down this node. */
+    /* fall through */
   case WSREP_FATAL:
     /* Cluster connectivity is lost.
      *