On Windows systems, occurrences of ERROR_SHARING_VIOLATION due to
conflicting share modes between processes accessing the same file can
result in CreateFile failures.
mysys' my_open() already incorporates a workaround by implementing
wait/retry logic on Windows.
But this does not help if files are opened using shell redirection like
mysqltest traditionally did it, i.e via
--echo exec "some text" > output_file
In such cases, it is cmd.exe, that opens the output_file, and it
won't do any sharing-violation retries.
This commit addresses the issue by introducing a new built-in command,
'write_line', in mysqltest. This new command serves as a brief alternative
to 'write_file', with a single line output, that also resolves variables
like "exec" would.
Internally, this command will use my_open(), and therefore retry-on-error
logic.
Hopefully this will eliminate the very sporadic "can't open file because
it is used by another process" error on CI.
The issue is that when recovery is about to create a new data or index
page it check if the page already exits.
If the page does not exists (file is too short) or contains wrong checksum,
then the recovery code will recreate the page.
The bug was that the code that checked if the page existed didn't take
into account encrypted pages.
Fixed by adding a check if page could not be encrypted solved the issue.
I also added some code to silence decryption errors for new pages.
Test case and some inspiration for how to solve this come from
the pull request by alexandr.miloslavsky
