[RFC] Change default PDO error mode to exceptions

[AllenJB]

RFC: https://wiki.php.net/rfc/pdo_default_errmode

I have implemented the change and updated the tests for pdo, pdo_sqlite and pdo_mysql.

It is quite possible additional PDO extension tests will need updating (specifically many tests never explicitly set the error mode), but I don't currently have working installs and thought I'd post something up for others to look at.

I did additionally update the pdo_mysql tests README with some notes on the permissions required for the MySQL user.

Some "points of interest" in the tests I updated:

• Several tests give double warnings, with the second warning containing less information. I verified this was existing behavior the same test code and a copy of PHP built from master with the same configure options on the same system (ie. do not have my change but are otherwise identical).
  • pdo\tests\bug_44159.phpt
  • pdo_sqlite\tests\pdo_fetch_func_001.phpt
• pdo_sqlite\tests\pdo_sqlite_transaction.phpt causes a "table is locked" error when attempting to drop the table at the end of the test, but I couldn't see why this occurred.
• ext/pdo_mysql/tests/pdo_mysql_pconnect.phpt: I updated this test to use silent mode. There's notes in the tests about errors not occurring with libmysql. Can libmysql still be used with PHP or is mysqlnd now the only option? Could the test be rewritten an improved?

[iluuu1994]

I guess we're not 100% consistent on this but the C file should be indented with tabs only.

[adambaratz]

I can confirm that no changes are needed for pdo_dblib. The tests for that extension already set the error mode to exceptions and expect those results.

[Llbe]

There are some bugs around the exception error mode that perhaps is more important to fix once this becomes the default mode.

False is returned and no exception is thrown: #4288

Warning is triggered instead of an exception: https://bugs.php.net/bug.php?id=74401

[nikic]

CI failures spurious.

[cmb69]

Can someone please check whether this needs changes for pdo_oci? cc @cjbj

[camporter]

pdo_oci test runs show no differences with master for the current test failures. Additionally, none of the failures are related to these changes as far as I can tell:

=====================================================================
FAILED TEST SUMMARY
---------------------------------------------------------------------
via [ext/pdo_oci/tests/common.phpt]
	OCI PDO Common: FR #71885 (Allow escaping question mark placeholders) [ext/pdo_oci/tests/bug_71885.phpt]
via [ext/pdo_oci/tests/common.phpt]
	OCI PDO Common: Bug #73234 (Emulated statements let value dictate parameter type) [ext/pdo_oci/tests/bug_73234.phpt]
PDO_OCI: PDOStatement->getColumnMeta [ext/pdo_oci/tests/pdo_oci_stmt_getcolumnmeta.phpt]
PDO OCI: Inserts 10K with 1 number and 2 LOB columns (stress test) [ext/pdo_oci/tests/pdo_oci_stream_2a.phpt]
=====================================================================

[cjbj]

@cmb69 @camporter that agrees with what I saw.

[AllenJB]

What still needs to be done before this PR can be merged? Is there anything more I need to do?

[kocsismate]

@AllenJB As far as I can tell, you should add an UPGRADING entry for this change

[cmb69]

Thanks for the RFC and the PR. Applied as 5075240.