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.
mtr uses group suffix, but some existing inc and test files use
server_id for expect files. This patch aims to fix that.
For spider:
With this change we will not have to maintain a separate version of
restart_mysqld.inc for spider, that duplicates code, just because
spider tests use different names for expect files, and shutdown_mysqld
requires magical names for them.
With this change spider tests will also be able to use other features
provided by restart_mysqld.inc without code duplication, like the
parameter $restart_parameters (see e.g. the testcase mdev_29904.test
in commit ef1161e5d4f).
Tests run after this change: default, spider, rocksdb, galera, using
the following command
mtr --parallel=auto --force --max-test-fail=0 --skip-core-file
mtr --suite spider,spider/*,spider/*/* \
--skip-test="spider/oracle.*|.*/t\..*" --parallel=auto --big-test \
--force --max-test-fail=0 --skip-core-file
mtr --suite galera --parallel=auto
mtr --suite rocksdb --parallel=auto
