MDEV-35937 InnoDB: Failing assertion: sym_node->table != NULL in pars_retrieve_table_def

[Thirunarayanan]

• The Jira issue number for this PR is: MDEV-35937

Description

• InnoDB tries to fetch the metadata about fulltext index for discarded tablespace and fails for discarded tablespace.
  In i_s_fts_config_fill(), i_s_fts_index_cache_fill() and i_s_fts_index_table_fill(), InnoDB needs to check whether
  the tablespace is discarded or accessable before accessing the fulltext auxiliary table. This issue doesn't exist in
  10.6+ version due to MDEV-19445(commit 0aa2bc7)

How can this PR be tested?

./mtr innodb_fts.innodb_fts_misc_1

If the changes are not amenable to automated testing, please explain why not and carefully describe how to test manually.

Basing the PR against the correct MariaDB version

• This is a new feature or a refactoring, and the PR is based against the main branch.
• This is a bug fix, and the PR is based against the earliest maintained branch in which the bug can be reproduced.

PR quality check

• I checked the CODING_STANDARDS.md file and my PR conforms to this where appropriate.
• For any trivial modifications to the PR, I am ok with the reviewer making the changes themselves.

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[dr-m]

I see that 0024524 had fixed this for another view. Shouldn’t also i_s_fts_index_cache_fill() and i_s_fts_index_table_fill() be fixed?

[dr-m]

I do not seem to fully understand the failure scenario. Is this bug specific to 10.5 only? If that is the case, the commit message needs to make it clear that this fix must be null-merged to 10.6.