Bumped priority to major because test failures introduces noise and doubt and slows down development

Running these tests, the version without /t of all these testcases (i.e. spider.spider_fixes instead of spider/t.spider_fixes etc.) works. there are roughly 3 kinds of problems:

1. Those sourcing slave_test_init.inc, including spider3_fixes_part, }}spider_fixes}}, spider_fixes_part, spider_fixes, slave_trx_isolation. This is caused by vars defined in spider/my.cnf not found and resolved to empty (e.g. $MASTER_1_MYPORT used in slave_test_init.inc and $STR_SEMICOLON used in init_master_1.inc. This causes parsing problem
2. Connection 'child2_1' not found, including error_row_number and udf_pushdown
3. "The MariaDB server is running with the --skip-partition option so it cannot execute this statement", including direct_join

It looks like mtr simply does not use path/to/my.cnf when testing path/to/t.foo. One can verify this with a silly one line test --echo $MASTER_1_MYPORT that prints out nothing.

So the "solution" is simply not to run tests with a /t. infix:

./mysql-test/mtr --suite spider,spider/*,spider/*/* --skip-test="spider/oracle.*|.*/t\..*" --parallel=auto --big-test --force --max-test-fail=0 --skip-core-file

When you run the suitename.testname, mtr loads my.cnf from the suite directory.
Test files can be directly in the suitename directory or in the t/ subdirectory.
When you specify spider/t.foo, mtr thinks that spider/t is the suite directory, and looks for spider/t/my.cnf and spider/t/foo.result.

serg I see, thanks for explaining. If only there's a simpler command to run all suites belonging to a directory recursively.