Re: [PATCH] use strbuf_addbuf() for appending a strbuf to another

Jeff King [off-list ref] writes:

I don't think we do. Going back to the original discussion:

  http://thread.gmane.org/gmane.comp.version-control.git/136141/focus=136774

it was mostly just "hey, this would fail really confusingly if we ever
did, so let's make it safe".

The second strbuf_grow() is by definition a noop (which is why 81d2cae
works at all), but we do pay the size-computation cost.

Both true.  If the second one is not a noop, nothing is fixed by
81d2cae at all, but it is subtle.

René's update makes it far easier to understand what is going on.

quoted

-- >8 --
Subject: strbuf: avoid calling strbuf_grow() twice in strbuf_addbuf()

Implement strbuf_addbuf() as a normal function in order to avoid calling
strbuf_grow() twice, with the second callinside strbud_add() being a
no-op.  This is slightly faster and also reduces the text size a bit.

Seems reasonable.  IMHO the main advantage is that one does not have to
reason about the double strbuf_grow() (i.e., that the strbuf_add() is
safe because we know its grow is a noop).

-Peff