Fix segfault when handling ChangeGroupSizeInUnits during VDisk LocalRecovery

[rosik]

Changelog category

• Not for changelog (changelog entry is not required)

Description for reviewers

• Add tests for Apply changes to PDiskExpectedSlotCount without restarting PDisk #21011
• Follow-up for Implement ChangeGroupSizeInUnits bscontroller command #19198

The test revealed the bug. During VDisk LocalRecovery the PDiskCtx is nullptr, which resulted in a segmentation fault when handling TEvVGenerationChange. The PDiskCtx is initialized wen handling TEvLocalRecoveryDone.

[github-actions]

🟢 2025-11-18 01:03:37 UTC The validation of the Pull Request description is successful.

[Copilot]

Pull Request Overview

This PR adds functional tests for the PDisk SlotSizeInUnits feature to validate the behavior of dynamic slot sizing for physical disks in the blob storage system.

Key Changes:

• Adds support for pdisk_config parameter in test harness configuration system
• Implements new API methods to query PDisk and storage group information via HTTP
• Adds helper methods to the kikimr client for managing blob storage configurations
• Refactors existing compatibility test to use centralized client methods

Reviewed Changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
ydb/tests/library/harness/kikimr_runner.py	Adds pdisk_config handling in __add_bs_box method for configuring PDisk settings
ydb/tests/library/harness/kikimr_config.py	Adds static_pdisk_config and dynamic_pdisks_config parameters and propagates them through PDisk initialization
ydb/tests/library/clients/kikimr_http_client.py	Adds HTTP API methods for querying storage groups and detailed PDisk information
ydb/tests/library/clients/kikimr_client.py	Adds blob storage configuration helper methods including read/define host configs, query base config, and update drive status
ydb/tests/functional/blobstorage/ya.make	Adds new test file to the build configuration
ydb/tests/functional/blobstorage/test_pdisk_slot_size_in_units.py	New test file implementing test cases for PDisk slot sizing feature
ydb/tests/compatibility/test_infer_pdisk_expected_slot_count.py	Refactored to use centralized client methods instead of duplicating logic

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[github-actions]

⚪ 2025-11-18 00:43:25 UTC Pre-commit check linux-x86_64-relwithdebinfo for 810d6bd has started.
⚪ 2025-11-18 00:44:00 UTC Artifacts will be uploaded here
⚪ 2025-11-18 00:46:44 UTC ya make is running...
🟡 2025-11-18 02:17:21 UTC Some tests failed, follow the links below. Going to retry failed tests...

Ya make output | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
39677	36802	0	4	2842	29

⚪ 2025-11-18 02:17:35 UTC ya make is running... (failed tests rerun, try 2)
🟡 2025-11-18 02:32:41 UTC Some tests failed, follow the links below. Going to retry failed tests...

Ya make output | Test bloat | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
72 (only retried tests)	54	0	1	0	17

⚪ 2025-11-18 02:32:48 UTC ya make is running... (failed tests rerun, try 3)
🟢 2025-11-18 02:40:40 UTC Tests successful.

Ya make output | Test bloat | Test bloat | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
36 (only retried tests)	21	0	0	0	15

🟢 2025-11-18 02:40:46 UTC Build successful.
🟢 2025-11-18 02:41:07 UTC ydbd size 2.3 GiB changed* by +1008 Bytes, which is < 100.0 KiB vs main: OK

ydbd size dash	main: d5e1860	merge: 810d6bd	diff	diff %
ydbd size	2 444 846 160 Bytes	2 444 847 168 Bytes	+1008 Bytes	+0.000%
ydbd stripped size	519 857 432 Bytes	519 857 816 Bytes	+384 Bytes	+0.000%

^{*please be aware that the difference is based on comparing your commit and the last completed build from the post-commit, check comparation}

[github-actions]

⚪ 2025-11-18 00:47:49 UTC Pre-commit check linux-x86_64-release-asan for 810d6bd has started.
⚪ 2025-11-18 00:48:14 UTC Artifacts will be uploaded here
⚪ 2025-11-18 00:50:55 UTC ya make is running...
🟢 2025-11-18 02:12:09 UTC ydbd size 3.8 GiB changed* by +2.5 KiB, which is < 100.0 KiB vs main: OK

ydbd size dash	main: d5e1860	merge: 810d6bd	diff	diff %
ydbd size	4 093 155 616 Bytes	4 093 158 144 Bytes	+2.5 KiB	+0.000%
ydbd stripped size	1 519 640 752 Bytes	1 519 641 968 Bytes	+1.2 KiB	+0.000%

^{*please be aware that the difference is based on comparing your commit and the last completed build from the post-commit, check comparation}