bug#49127: Performance degradation in encode_coding_object

[Mattias Engdegård]

16 aug. 2021 kl. 20.50 skrev Eli Zaretskii <eliz@gnu.org>:

> It does, if both src_object and dst_object are the same (current)
> buffer.

There is nothing in that function or in the comment describing it which says 
that the current buffer must be either. It costs us nothing to use the correct 
value so that's what we should do.

> How can we be sure this reproduces the original issue?  The original
> issue was reported from a real-life use case, not from a toy program.

Because I have read and tested the original code as well, which is how that toy 
program that reproduces the problem in a simpler but qualitatively equivalent 
way came to be. The patch fixes the symptoms of both the toy program and the 
real-life use case.

> Thanks, but this is not the whole story with that problem in
> encode_coding_object.

What is the whole story then?