[vim/vim] tab drop triggers BufUnload (Issue #18893)

Toby She

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Dec 8, 2025, 9:46:24 PM12/8/25

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otomn created an issue (vim/vim#18893)

Steps to reproduce

:set shortmess+=F
:au BufUnload * echo "BufUnload " . expand("%")
:e test
:tab drop test

Expected behaviour

"BufUnload test" is printed but it should not be printed.

Version of Vim

9.0

Environment

Mac, WSL

Logs and stack traces

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zeertzjq

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Dec 8, 2025, 9:49:31 PM12/8/25

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zeertzjq left a comment (vim/vim#18893)

This seems to be a regression from patch 9.1.0046.

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Toby She

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Dec 8, 2025, 9:53:40 PM12/8/25

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otomn left a comment (vim/vim#18893)

Note: tab drop does not trigger BufUnload on 9.0. But, e does trigger BufUnload on 9.0.

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Christian Brabandt

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Dec 28, 2025, 10:29:18 AM12/28/25

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chrisbra left a comment (vim/vim#18893)

Also, this still happens for :drop if test is an empty file, but doesn't happen if test is non-empty.

That is because of 9781788

I am not sure what the correct behaviour should be. If we comment out part of the patch that triggers ex_rewind, it won't trigger the BufUnload anymore, but the file would also not be loaded. So I think it should go through do_ecmd() (which will then trigger the BufUnload again).

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Ferne

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Jan 29, 2026, 10:32:19 AM (12 days ago) Jan 29

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aliferne left a comment (vim/vim#18893)

How about changing the file ex_cmds.c in line 5749

ex_all(eap);
cmdmod.cmod_tab = 0;
ex_rewind(eap);

to

ex_all(eap);
cmdmod.cmod_tab = 0;
open_buffer(FALSE, eap, 0);

If do so, the problem when call :tab drop test seems to be fixed, and the file loads well on my computer.

I'm not familiar with the vim kernel but this solution works on my computer.

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Christian Brabandt

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Feb 9, 2026, 2:47:13 PM (20 hours ago) Feb 9

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chrisbra left a comment (vim/vim#18893)

IIRC that open_buffer leaked memory, see the details in the commits mentioned above.