Silly but deadly mistakes caught by MTR!

I don’t mind highlighting them; but for records’ sake, TODO: squash

Author: ParadoxV5

sql/rpl_info_file.hh

@@ -158,7 +158,7 @@ struct InfoFile
     /// @param other not `nullptr`
     auto &operator=(const char *other)
     {
-      strmake_buf(this->buf, other);
+      strmake(buf, other, size-1);
       return *this;
     }
     virtual bool load_from(IO_CACHE *file) override
@@ -245,35 +245,38 @@ protected:
     std::from_chars_result result= std::from_chars(
       field1.buf, &field1.buf[sizeof(field1.buf)], lines);
     // Skip the first field in the for loop if that line was not a line count.
-    size_t i= result.ec != IntIOCache::ERRC_OK || *(result.ptr) != '\n';
+    size_t i= result.ec != IntIOCache::ERRC_OK || *(result.ptr) != '\0';
     /**
       Set the default after parsing: While std::from_chars() does not replace
       the output if it failed, it does replace if the line is not fully spent.
     */
     if (i)
       lines= default_lines;
-    size_t fields_count= MY_MIN(lines, fields.size());
-    for (; i < fields_count; ++i)
+    for (; i < lines; ++i)
     {
-      const mem_fn &pm= fields.begin()[i];
-      if (static_cast<bool>(pm) && pm(this).load_from(&file))
-        return true;
-    }
-    /*
-      Count and discard remaining lines if the line count runs beyond `fields`.
-      This is especially to prepare for @ref MasterInfoFile for MariaDB 10.0+,
-      which reserves a bunch of lines before its unique `key=value` section
-      to accomodate any future line-based (old-style) additions in MySQL.
-      (This will make moving from MariaDB to MySQL easier by not
-       requiring MySQL to recognize MariaDB `key=value` lines.)
-    */
-    while (i < lines)
-      switch (my_b_get(&file)) {
-      case my_b_EOF:
-        return true; // EOF already?
-      case '\n':
-        ++i;
+      char c;
+      if (i < fields.size()) // line known in the ` list
+      {
+        const mem_fn &pm= fields.begin()[i];
+        if (static_cast<bool>(pm))
+        {
+          if (pm(this).load_from(&file))
+            return true;
+          continue;
+        }
       }
+      /*
+        Count and discard unrecognized lines.
+        This is especially to prepare for @ref MasterInfoFile for MariaDB 10.0+,
+        which reserves a bunch of lines before its unique `key=value` section
+        to accomodate any future line-based (old-style) additions in MySQL.
+        (This will make moving from MariaDB to MySQL easier by not
+        requiring MySQL to recognize MariaDB `key=value` lines.)
+      */
+      while ((c= my_b_get(&file)) != '\n')
+        if (c == my_b_EOF)
+          return true; // EOF already?
+    }
     return false;
   }
 
@@ -298,9 +301,13 @@ protected:
       of effective lines in the first line of the file.
     */
     IntIOCache::to_chars(&file, lines);
+    my_b_write_byte(&file, '\n');
     for (const mem_fn &pm: fields)
+    {
       if (static_cast<bool>(pm))
         pm(this).save_to(&file);
+      my_b_write_byte(&file, '\n');
+    }
     /*
       Pad additional reserved lines:
       (1 for the line count line + field count) inclusive -> max line inclusive

sql/rpl_master_info_file.hh

@@ -84,7 +84,7 @@ struct MasterInfoFile: InfoFile
       optional.emplace(value);
       return *this;
     }
-    bool is_default() override { return optional.has_value(); }
+    bool is_default() override { return !optional.has_value(); }
     bool set_default() override
     {
       optional.reset();
@@ -214,25 +214,21 @@ struct MasterInfoFile: InfoFile
       /// +1 for the terminating delimiter
       char buf[IntIOCache::BUF_SIZE<uint32_t> + 1];
       for (i=0; i < sizeof(buf); ++i)
-        switch (int c= my_b_get(file)) {
-        case my_b_EOF:
+      {
+        int c= my_b_get(file);
+        if (c == my_b_EOF)
           return true;
-        case ' ': // End of Field
-        case '\n': // End of Line
-          goto break_for1;
-        default:
-          buf[i]= c;
-        }
-      break_for1:
+        buf[i]= c;
+        if (c == /* End of Line */ '\n' || c == /* End of Count */ ' ')
+          break;
+      }
       /*
         * std::from_chars() fails if `count` will overflow in any way.
         * exclusive end index of the string = size
       */
       std::from_chars_result result= std::from_chars(buf, &buf[i], count);
-      if (result.ec != IntIOCache::ERRC_OK)
-        return true;
       // Reserve enough elements ahead of time.
-      if (allocate_dynamic(&array, count))
+      if (result.ec != IntIOCache::ERRC_OK || allocate_dynamic(&array, count))
         return true;
       while (count--)
       {
@@ -244,20 +240,18 @@ struct MasterInfoFile: InfoFile
         if (*(result.ptr) != ' ')
           return true;
         for (i=0; i < sizeof(buf); ++i)
+        {
           /*
             Bottlenecks from repeated IO does not affect the
             performance of reading char by char thanks to the cache.
           */
-          switch (int c= my_b_get(file)) {
-          case my_b_EOF:
+          int c= my_b_get(file);
+          if (c == my_b_EOF)
             return true;
-          case ' ': // End of Field
-          case '\n': // End of Line
-            goto break_for2;
-          default:
-            buf[i]= c;
-          }
-        break_for2:
+          buf[i]= c;
+          if (c == /* End of Count */ ' ' || c == /* End of Line */ '\n')
+            break;
+        }
         result= std::from_chars(buf, &buf[i], value);
         if (result.ec != IntIOCache::ERRC_OK)
           return true;
@@ -359,7 +353,7 @@ struct MasterInfoFile: InfoFile
       return *this;
     }
     bool is_default() override
-    { return mode <= enum_master_use_gtid::DEFAULT; }
+    { return mode >= enum_master_use_gtid::DEFAULT; }
     bool set_default() override
     {
       mode= enum_master_use_gtid::DEFAULT;
@@ -446,7 +440,7 @@ struct MasterInfoFile: InfoFile
       {
         my_b_write(file, (const uchar *)buf, size - 3);
         my_b_write_byte(file, '.');
-        my_b_write(file, &(const uchar &)result.ptr[-3], 3);
+        my_b_write(file, (const uchar *)(&result.ptr[-3]), 3);
       }
       else
       {
@@ -480,7 +474,7 @@ struct MasterInfoFile: InfoFile
     &MasterInfoFile::master_ssl_key,
     &MasterInfoFile::master_ssl_verify_server_cert,
     &MasterInfoFile::master_heartbeat_period,
-    // &MasterInfoFile::master_bind, // MDEV-19248
+    nullptr, // &MasterInfoFile::master_bind, // MDEV-19248
     &MasterInfoFile::ignore_server_ids,
     nullptr, // MySQL field `master_uuid`, which MariaDB ignores.
     &MasterInfoFile::master_retry_count,

sql/sql_repl.cc

@@ -4103,13 +4103,13 @@ bool change_master(THD* thd, Master_info* mi, bool *master_info_added)
     mi->master_ssl_verify_server_cert=
       (lex_mi->ssl_verify_server_cert == LEX_MASTER_INFO::LEX_MI_ENABLE);
 
-  mi->master_ssl_ca     = lex_mi->ssl_ca;
-  mi->master_ssl_capath = lex_mi->ssl_capath;
-  mi->master_ssl_cert   = lex_mi->ssl_cert;
-  mi->master_ssl_cipher = lex_mi->ssl_cipher;
-  mi->master_ssl_key    = lex_mi->ssl_key;
-  mi->master_ssl_crl    = lex_mi->ssl_crl;
-  mi->master_ssl_crlpath= lex_mi->ssl_crlpath;
+  if (lex_mi->ssl_ca)      mi->master_ssl_ca     = lex_mi->ssl_ca;
+  if (lex_mi->ssl_capath)  mi->master_ssl_capath = lex_mi->ssl_capath;
+  if (lex_mi->ssl_cert)    mi->master_ssl_cert   = lex_mi->ssl_cert;
+  if (lex_mi->ssl_cipher)  mi->master_ssl_cipher = lex_mi->ssl_cipher;
+  if (lex_mi->ssl_key)     mi->master_ssl_key    = lex_mi->ssl_key;
+  if (lex_mi->ssl_crl)     mi->master_ssl_crl    = lex_mi->ssl_crl;
+  if (lex_mi->ssl_crlpath) mi->master_ssl_crlpath= lex_mi->ssl_crlpath;
 
 #ifndef HAVE_OPENSSL
   if (lex_mi->ssl || lex_mi->ssl_ca || lex_mi->ssl_capath ||