Hi Serg, Ok the patch moving in the right direction but it's not there, yet. Please find the input below. First, input on the commit comment. Please consider it as a request applying to ALL further commits to the MariaDB codebase.

MDEV-23766: implemented requested debug checks

Imagine somebody looking at this in a few years. Will they know what checks were requested? They might get a clue by looking at the Jira text, but the idea to make the commit comments concise and self-contained descriptions. Something like this: Line #1: one-line description of the patch:

...

MDEV-23766: Make attempts to write invalid JSON cause assertion failures

Subsequent lines:

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Make JSON writing API (class Json_writer) check the produced JSON document is valid. The following checks are made: - JSON objects must contain named members - JSON arrays must contain unnamed members. - (TODO: add other restrictions we're enforcing).

It is not clear how the checker interacts with Single_line_formatting_helper. The code like one the one I'm quoting below shows some non-trivial overlap:

@@ -28,7 +36,16 @@ void Json_writer::append_indent()

void Json_writer::start_object() { +#ifndef NDEBUG + DBUG_ASSERT(got_name == named_item_expected()); + named_items_expectation.push_back(true); + size_t depth= named_items_expectation.size(); +#endif fmt_helper.on_start_object(); +#ifndef NDEBUG + if (depth != named_items_expectation.size()) + named_items_expectation.pop_back(); +#endif

if (!element_started) start_element();

This looks very cryptic. Can you elaborate about this? BR Sergei -- Sergei Petrunia, Software Developer MariaDB Corporation | Skype: sergefp | Blog: http://petrunia.net