Bug #90314 mysqldump --tab does not determine file names correctly
Submitted: 5 Apr 2018 17:52 Modified: 23 Sep 5:17
Reporter: Manuel Ung Email Updates:
Status: Duplicate Impact on me:
None 
Category:MySQL Server: mysqldump Command-line Client Severity:S3 (Non-critical)
Version:5.6 8.0, 5.6.39, 5.7.21 OS:Any
Assigned to: CPU Architecture:Any

[5 Apr 2018 17:52] Manuel Ung
Description:
When running mysqldump on a table containing the character '.', fn_format fails to append the ".sql" and ".txt" extensions onto the output files.

How to repeat:
CREATE TABLE `t.t` (i int);

mysqldump --tab=... test t

Suggested fix:
Pass the MY_APPEND_EXT flag to fn_format.
[6 Apr 2018 5:10] MySQL Verification Team
Hello Manuel Ung,

Thank you for the report and feedback.
Observed this with 5.6.39, 5.7.21 builds.

Thanks,
Umesh
[8 Nov 2018 1:02] Manuel Ung
Fixed here
https://github.com/mysql/mysql-server/commit/72ae49de03a798e9c4714903e2d013ed17d17b85

Bug #28380961: CONTRIBUTION BY FACEBOOK: ADD MY_APPEND_EXT FLAG WHEN

  DETERMINING FILE NAME ...

Ensure that mysqldump always adds the extension to file names for tables
when --tabe is used.
Added a test.
[23 Sep 5:16] MySQL Verification Team
This is fixed in 8.0.13 after Bug #91745 implemented.

For mysqldump --tables output, file names now always include a .txt
or .sql suffix, even for file names that already contain a dot.
Thanks to Facebook for the contribution.