Look at me, I'm an (LLM-assisted) Emacs Lisp developer now

Claude Code came out in February and I was hooked immediately. Luckily for me Anthropic introduced flat rate pricing plans very soon afterwards, or I'd have been bankrupted by pay-per-token prices by summer. I tried to channel all that newly-developed addiction to something productive, and decided to write, greenfield, some Emacs Lisp packages. I think such projects are perfectly-sized for working with Claude Code: for smaller tasks the regular chat interface worked fine (although now Claude Code handles those for me too), and for larger tasks one needs to start paying more attention to context management.

So I wrote three Emacs Lisp packages, all related to LLMs (yeah there is some infinite recursion going on here. I guess it all stops at the singularity):

• mcp-server-lib.el: an Emacs Lisp library for writing Model Context Protocol (MCP) servers, running in Emacs. MCP is a protocol allowing LLMs to call tools and read things in a structured way.
• elisp-dev-mcp: an MCP server for developing Emacs Lisp.
• org-mcp: an MCP server for reading and updating Emacs Org tasks.

All three packages have been published on MELPA (which is like npm registry, but for Elisp), and the first package (the library one) is surprisingly popular, with about 1,700 installs as of today.

Obviously I learned a lot about LLM-assisted development too but so far I am not planning to blog about that specifically, as things move faster than my ability to draft and publish and there are some very good guides out there.

Building and testing MySQL 8.0.44 / 8.4.7 / 9.5.0 releases on macOS

Oracle MySQL 8.0.44 / 8.4.7 / 9.5.0 are out and it's time for me to build and run their tests on macOS, Apple Silicon hardware. I have skipped the review of the previous set of releases this summer due to personal reasons, so this covers the delta from 8.0.42 / 8.4.5 / 9.3.0, out in spring.

Build

No need to use any of the bundled 3rd party libraries, and the current XCode (26.0.1) compiles all the releases. As usual, things get more interesting with Homebrew-packaged LLVM. All releases fail to build with LLVM 17 and lower versions with a bizarre CMake error, which may have to do more with the newer macOS version 26 than MySQL. LLVM 18 and 19 build fine.

8.0.44: does not build with 20 & 21:

• Bug #119238 Compilation error with clang 20
• Bug #119239 Compilation error with clang 21

8.4.7: builds with LLVM 20, and 21 has a different error than 8.0.44: Bug #119242 8.4.7 fails to build with clang 21.

9.5.0: builds with LLVM 20, and 21 has a different error from both 8.0.44 and 8.4.7: Bug #119246 9.5.0 compilation error with LLVM 21

The newest compiler errors are, unfortunately, expected. So, all in all, things are looking good here.

Tests

A lot of churn here over the past two releases.

Bad news:

• Bug #99063 perfschema.idx_compare_ees_by_thread_by_error is unstable - open since 8.0.19, but I only encountered it now
• Bug #119247 Test main.log_buffered-big failure
• Bug #119249 routertest_integration_routing_direct test failure
• Bug #119250 routertest_integration_routing_sharing_constrained_pools missing connection_pool.so
• Bug #119251 Test rpl.rpl_seconds_behind_master failure
• Bug #119252 Test router.response_cache failure
• Bug #119253 innodb.tablespace_encrypt_9 crashing the server with assertion failure
• Bug #119254 Clone, x, innodb, and component_keyring tests fail on copy_file command
• Bug #119258 routertest_integration_routing_direct tests failing to login

No news, aka previously reported bugs with no to little changes:

• Bug #113189 ColumnStatisticsTest.StoreAndRestoreAttributesEquiHeight unit test fails
• Bug #113190 Several tests in routertest_integration_routing_sharing_constrained_pools fail
• Bug #113260 Client error in error log: MY-004031 - The client was disconnected …
• Bug #113665 perfschema.relaylog fails with a result difference
• Bug #113709 StrXfrmTest.ChineseUTF8MB4 failing with an AddressSanitizer error
• Bug #113722 Test main.index_merge_innodb failing with a result difference, fixed in 9.2.0, still happens on 8.0.44.
• Bug #115480 Test innodb.log_first_rec_group failing
• Bug #116369 rpl.rpl_semi_sync_alias crashes under AddressSanitizer, but only on 8.0.44, does not fail on 8.4.7, and the test looks gone in 9.5.0.
• Bug #116373 auth_sec.acl_tables_row_locking failing with result diff
• Bug #116378 routertest_integration_routing_splitting crashing under AddressSanitizer - not sure whether it's fixed or became an intermittent issue. Filing under "no news" for now
• Bug #116394 Test binlog_gtid.binlog_gtid_binlog_recovery_errors crashes with an assert
• Bug #118169 Test innodb.partition_upgrade_8019_mac_lctn_2_debug failing - might have been downgraded from a reliable failure to an intermittent one
• Bug #118171 Test main.mysqldump-tablespace-escape failing
• Bug #118185 Non-specific ASan error on TestLoaderGood/LoaderReadTest.load_wrong_version/0
• Bug #118213 Test perfschema.idx_compare_mutex_instances fails under debug + sanitizers

Good news:

• Bug #103338 Starting mysqld on same data files sometimes errors out due to doublewrite buf - could not reproduce it anymore, but now there is bug 119247 on the same testcase
• Bug #116372 ODR violation reported by AddressSanitizer for plugin variables
• Bug #116375 UBSan error on Rpl_commit_order_queue_test.Simulate_mts
• Bug #117297 Test rpl.rpl_json failing
• Bug #117314 Test innodb.tablespace_encrypt_9 failing - but see bug 119253
• Bug #118170 Test innodb.partition_upgrade_8019_win_lctn_2_debug failing instead of skipping on macos - the test actually passes (!) on 8.0.44 and 8.4.7, and is disabled on 9.5.0.
• Bug #118175 UBSan error at x/protocol/stream/decompression_input_stream.h
• Bug #118185 Non-specific ASan error on TestLoaderGood/LoaderReadTest.load_wrong_version/0
• Bug #118193 Test innodb.partition_upgrade_5727_mac_lctn_2 failing with a result difference
• Bug #118211 Spec/ShareConnectionReconnectTest.change_user/ssl_modes_REQUIRED__PREFERRED_socket test fails
• Bug #118212 Some router tests crash under AddressSanitizer
• Bug #118214 LifecycleTest.Simple_AllFunctions crashes under AddressSanitizer

One-off issues:

• merge_innodb-t on 8.0.44 and 8.4.7, debug + sanitizers build
• gcs_xcom_control_interface on 8.0.44 and 9.5.0 release builds
• routertest_integration_routing_direct on 8.0.44 release build
• binlog_gtid.binlog_check_gtid_persistor_compatibility crashed on 8.4.7 debug build
• rpl_gtid.rpl_gtids_table_disable_binlog_on_slave result difference on 8.4.7 debug build
• innodb.trigger_function_lock_compare timeout on 8.4.7 debug build
• routertest_integration_routing_splitting on 8.4.7 debug w/ sanitizers builds, maybe Bug #116378 routertest_integration_routing_splitting crashing under AddressSanitizer, but was not able to confirm
• perfschema.keyring_keys result difference on 8.4.7 release build
• json.array_index result difference on 9.5.0 debug w/ sanitizers build
• perfschema.error_log result difference on 9.5.0 debug w/ sanitizers build
• main.slow_log result difference on 9.5.0 debug w/ sanitizers build
• router.app_specific_metadata_v_latest result difference on 9.5.0 release build
• innodb_undo.truncate test assertion failure on 9.5.0 debug build

Conclusion

Without the one-offs I have 9 new, 15 unchanged, and 12 fixed bugs. At last the fixed ones outnumber the new ones, hopefully this trend will continue.

Building and testing MySQL 8.0.42 / 8.4.5 / 9.3.0 on macOS

Previously: 8.0.41 / 8.4.4 / 9.2.0

MySQL 8.0.42 / 8.4.5 / 9.3.0 are out, and as usual, I have built and tested the new releases on macOS, due to its popularity as the server OS, of course.

Build

The 8.0 series don't build with the current XCode clang because of bug 118026 (Build failed with apple clang 17). That's inconvenient, but Homebrew-packaged LLVM clang versions 14 to 18 build it fine.

Another pre-existing build bug 117299 (ddl0bulk.h:236:15: error: parameter 'prebuilt' not found in the function declaration [-Werror,-Wdocumentation]) previously only affected 8.0, but now hits 8.4. Of course, the workarounds are simple enough.

I have also reported bug 118161 (Having Homebrew-installed googletest breaks build). I suspect this is not a 8.0.42 regression, thus will not be counting towards the running bug totals.

So, for build, we have one bug with no change, and one slightly worsened. Meh, but not too bad either.

Test

Here the things are not looking as good.

Bad news first. New bugs and existing bugs with substantial regressions. The number is substantial:

• https://bugs.mysql.com/bug.php?id=116369 (rpl.rpl_semi_sync_alias crashes under AddressSanitizer) - was 8.0-only, now 9.3.0 crashes too at a different point.
• https://bugs.mysql.com/bug.php?id=118169 (Test innodb.partition_upgrade_8019_mac_lctn_2_debug failing)
• https://bugs.mysql.com/bug.php?id=118170 (Test innodb.partition_upgrade_8019_win_lctn_2_debug failing instead of skipping on macos)
• https://bugs.mysql.com/bug.php?id=118171 (Test main.mysqldump-tablespace-escape failing)
• https://bugs.mysql.com/bug.php?id=118175 (UBSan error at x/protocol/stream/decompression_input_stream.h)
• https://bugs.mysql.com/bug.php?id=118184 (UBSan errors on router tests)
• https://bugs.mysql.com/bug.php?id=118185 (Non-specific ASan error on TestLoaderGood/LoaderReadTest.load_wrong_version/0)
• https://bugs.mysql.com/bug.php?id=118193 (Test innodb.partition_upgrade_5727_mac_lctn_2 failing with a result difference)
• https://bugs.mysql.com/bug.php?id=118211 (Spec/ShareConnectionReconnectTest.change_user/ssl_modes_REQUIRED__PREFERRED_socket test fails)
• https://bugs.mysql.com/bug.php?id=118212 (Some router tests crash under AddressSanitizer)
• https://bugs.mysql.com/bug.php?id=118213 (Test perfschema.idx_compare_mutex_instances fails under debug + sanitizers)
• https://bugs.mysql.com/bug.php?id=118214 (LifecycleTest.Simple_AllFunctions crashes under AddressSanitizer)

Bugs with no news:

• https://bugs.mysql.com/bug.php?id=103338 (Starting mysqld on same data files sometimes errors out due to doublewrite buf)
• https://bugs.mysql.com/bug.php?id=113189 (ColumnStatisticsTest.StoreAndRestoreAttributesEquiHeight unit test fails)
• https://bugs.mysql.com/bug.php?id=113190 (Several tests in routertest_integration_routing_sharing_constrained_pools fail)
• https://bugs.mysql.com/bug.php?id=113260 (Client error in error log: MY-004031 - The client was disconnected …)
• https://bugs.mysql.com/bug.php?id=113665 (perfschema.relaylog fails with a result difference)
• https://bugs.mysql.com/bug.php?id=113709 (StrXfrmTest.ChineseUTF8MB4 failing with an AddressSanitizer error)
• https://bugs.mysql.com/bug.php?id=113722 (Test main.index_merge_innodb failing with a result difference) - was closed for 9.2.0, still happens on 8.4.5.
• https://bugs.mysql.com/bug.php?id=115480 (Test innodb.log_first_rec_group failing)
• https://bugs.mysql.com/bug.php?id=116373 (auth_sec.acl_tables_row_locking failing with result diff)
• https://bugs.mysql.com/bug.php?id=116375 (UBSan error on Rpl_commit_order_queue_test.Simulate_mts) - no change in the current release but already closed for the next ones, looking forward to confirming.
• https://bugs.mysql.com/bug.php?id=116378 (routertest_integration_routing_splitting crashing under AddressSanitizer)
• https://bugs.mysql.com/bug.php?id=116394 (Test binlog_gtid.binlog_gtid_binlog_recovery_errors crashes with an assert)
• https://bugs.mysql.com/bug.php?id=117297 (Test rpl.rpl_json failing)
• https://bugs.mysql.com/bug.php?id=117314 (Test innodb.tablespace_encrypt_9 failing)

Closed bugs or bugs that have improved in some ways:

• https://bugs.mysql.com/bug.php?id=114892 (Test XComControlTest.SuspectMemberFailedRemovalDueToMajorityLoss fails) - this one is intermittent with low enough frequency that I cannot tell whether it was fixed.
• https://bugs.mysql.com/bug.php?id=116385 (Test main.mysql_upgrade_grant timing out on debug build)

Did not test:

• https://bugs.mysql.com/bug.php?id=116372 (ODR violation reported by AddressSanitizer for plugin variables)

One-off issues that I wasn't able to repeat properly for bug reporting.

• rpl_gtid.rpl_gtids_table_disable_binlog_on_slave on 8.0.42
• rpl_gtid.rpl_gtid_create_select on 8.0.42
• test_services.test_table_access on 8.0.42
• main.system_variable_source on 8.0.42
• innodb.trigger_function_lock_compare on 8.0.42
• gcs_xcom_control_interface-t on 8.0.42 and 9.3.0
• router.authentication_mysql_accounts on 9.3.0
• routertest_integration_routing_sharing on 9.3.0
• routertest_integration_routing_sharing_constrained_pools on 9.3.0
• rpl_nogtid.rpl_semi_sync_uninstall_plugin on 9.3.0
• perfschema.idx_compare_events_waits_history on 9.3.0
• sys_vars.log_slow_admin_statements_func on 9.3.0
• main.subquery_mat_all on 9.3.0

Conclusion

Without the one-off issues I have 13 (!) new, 15 unchanged, 2 fixed, and 1 untested bug. The positive trend of the previous set of releases is no more, and the set of open issues almost doubles in size. I hope that the next quarterly release will look better.

Building and testing MySQL 8.0.41 / 8.4.4 / 9.2.0 on macOS

Previously: 8.0.40 / 8.4.3 / 9.1.0

Oracle released MySQL 8.0.41 / 8.4.4 / 9.2.0, and it's time for me to build and test it under macOS, of all things!

But first, a detour to the last set of releases Valgrind results, because its run took a few weeks on 9.1.0, and that's without --big-test. A big part of tests timed out, or failed randomly. There appear no errors that are diagnosed during server operation, and the shutdown logs are way too verbose for me to try to find any memory leaks. Perhaps 9.2.0 will fare better, and I will reduce --parallel further. Will it take two months to run? We will see!

Build

Mostly good news here, again. -DWITH_ZLIB=bundled is no longer required, that's probably due to newer XCode toolchain finally updating its zlib.

A new build bug:

• https://bugs.mysql.com/bug.php?id=117299 (ddl0bulk.h:236:15: error: parameter 'prebuilt' not found in the function declaration [-Werror,-Wdocumentation]) - the workaround is trivial.

A fixed build bug:

• https://bugs.mysql.com/bug.php?id=113113 (Build failure with Homebrew LLVM 14-19 on macOS) no longer happens with 8.4.4 and 9.2.0, but 8.0.41 is still affected.

MySQL 8.0.41 does not build with LLVM 19. It could probably be fixed by backporting a fix for MySQL 8.4.4 which is documented as "Implemented the standards-compliant my_char_traits<unsigned char> for use as a drop-in replacement for std::char_traits<unsigned char>, which was deprecated in Clang 18 and removed in Clang 19. (Bug #37273525)"

Test

New bugs:

• https://bugs.mysql.com/bug.php?id=117297 (Test rpl.rpl_json failing)
• https://bugs.mysql.com/bug.php?id=117314 (Test innodb.tablespace_encrypt_9 failing)

No changes:

• https://bugs.mysql.com/bug.php?id=113260 (Client error in error log: MY-004031 - The client was disconnected …)
• https://bugs.mysql.com/bug.php?id=116373 (auth_sec.acl_tables_row_locking failing with result diff)
• https://bugs.mysql.com/bug.php?id=115480 (Test innodb.log_first_rec_group failing)
• https://bugs.mysql.com/bug.php?id=113189 (ColumnStatisticsTest.StoreAndRestoreAttributesEquiHeight unit test fails)
• https://bugs.mysql.com/bug.php?id=113190 (Several tests in routertest_integration_routing_sharing_constrained_pools fail)
• https://bugs.mysql.com/bug.php?id=113709 (StrXfrmTest.ChineseUTF8MB4 failing with an AddressSanitizer error)
• https://bugs.mysql.com/bug.php?id=116375 (UBSan error on Rpl_commit_order_queue_test.Simulate_mts)
• https://bugs.mysql.com/bug.php?id=113665 (perfschema.relaylog fails with a result difference)
• https://bugs.mysql.com/bug.php?id=116385 (Test main.mysql_upgrade_grant timing out on debug build)
• https://bugs.mysql.com/bug.php?id=116378 (routertest_integration_routing_splitting crashing under AddressSanitizer)
• https://bugs.mysql.com/bug.php?id=113722 (Test main.index_merge_innodb failing with a result difference)
• https://bugs.mysql.com/bug.php?id=114892 (Test XComControlTest.SuspectMemberFailedRemovalDueToMajorityLoss fails) - this one I haven't seen in a while, but it's back
• https://bugs.mysql.com/bug.php?id=116394 (Test binlog_gtid.binlog_gtid_binlog_recovery_errors crashes with an assert)

Fixed bugs:

• https://bugs.mysql.com/bug.php?id=115495 ("Unable to read page" crash on innodb.dblwr_encrypt_recover)
• https://bugs.mysql.com/bug.php?id=116390 (Test main.opt_hint_resource_group_hypergraph failing testcase check)
• https://bugs.mysql.com/bug.php?id=116391 (Test main.opt_hints_join_order_hypergraph failing with a result diff)
• https://bugs.mysql.com/bug.php?id=115498 (Test main.opt_hints_hypergraph always failing)

Did not test:

• https://bugs.mysql.com/bug.php?id=116372 (ODR violation reported by AddressSanitizer for plugin variables)

One-off issues:

• main.join_cache_nojb failed once with query execution plan difference on 8.0.41 debug build.
• rpl_gtid.rpl_gtids_table_disable_binlog_on_slave failed intermittently on 8.0.41 Debug with sanitizers, 8.4.4 Debug, & 8.4.4 Debug with sanitizers builds. The same happened in the previous set of releases too.
• binlog_gtid.binlog_gtid_bgc_ticket_manager failed once on 8.4.4 Debug build.
• routertest_integration_routing_sharing_constrained_pools failed once in a way that is not bug #113190 above.
• rpl_gtid.rpl_heartbeat_log_pos_4gb timed out once on 8.4.4 Debug with sanitizers.
• binlog_gtid.binlog_check_gtid_persistor_compatibility failed once on 9.2.0 Debug with sanitizers.
• innodb.trigger_function_lock_compare timed out once on 9.2.0 Debug with sanitizers.

Conclusion

Without the one-off issues I have 2 new, 13 unchanged, 4 fixed, 1 untested bug. Much less churn than the last time, and finally the trend is positive.