Commits e49c0fb04 (unmap: fail if the mapping is currently executing,
2023-05-14) 42be0057a (map: fail if key is currently executing,
2023-06-24) fixed potential use-after-free issues. By doing so,
it broke configurations that in practice have not triggered any
crashes [1] [2].
For example with,
set -remove global autocomplete insert
hook global InsertCompletionShow .* %{
map window insert <esc> <c-o>
}
hook global InsertCompletionHide .* %{
unmap window insert <esc> <c-o>
}
The execution of the <esc> mapping triggers InsertCompletionHide fails
at unmapping. This seems legit and I don't see an obvious alternative
way to write it (InsertIdle would not be correct though it would work
in practice).
Fix the regression by allowing map and unmap again while keeping the
mappings alive until they have finished executing.
Applying map/unmap immediately seems like the most obvious semantics.
Alternatively, we could apply them in between key presses.
[1]: <https://github.com/kak-lsp/kak-lsp/issues/689>
[2]: <https://github.com/alexherbo2/auto-pairs.kak/issues/60>
If during execution of a mapping, that same mapping is replaced,
there is undefined behavior because we destroy a mapping that we are
still iterating over.
I have been using this mapping inside my kakrc to re-source the kakrc.
map global user s %{:source "%val{config}/kakrc"<ret>} -docstring 'source "%val{config}/kakrc"'
Now <space>s happens to not trigger undefined behavior because the
mapping stays the same.
However it triggers an assertion added by Commit e49c0fb04 (unmap:
fail if the mapping is currently executing, 2023-05-14), specifically
the destructor of ScopedSetBool that guards mapping execution.
Fix these by banning map of a key that is executing, just like we
did for unmap.
Alternative solution: we could allow mapping (and even unmapping)
keys at any time and keep them alive by moving them into a trash can,
like we do for clients and others.
