Andy Whitcroft <apw@xxxxxxxxxxxx> writes:
> I've been having trouble with git push apparently resending the entire
> commit trace for the branch each and every time I push. Poking at the
> source it seems this is due to a length limit on reference names as
> pulled from the remote repository.
>
> When we are building the pack to send we are sent a list of remote
> heads. get_remote_heads() reads these in, validates them and finally
> adds them to the remote_refs list. Part of the validation is a simple
> check for size and form; check_ref().
>
> static int check_ref(const char *name, int len, unsigned int flags)
> {
> if (!flags)
> return 1;
>
> if (len > 45 || memcmp(name, "refs/", 5))
> return 0;
> [...]
> }
>
> With the refs/heads/ prefix included this limits the head names to 34
> characters. From what I can see there is no good reason for this limit
> to be so low. I can see we don't want the remote end bloating us out of
> control, but we are already limiting the lines which contain these
> references to 1000 bytes and making no attempt to limit the number of
> them the remote server can send us. There seems to be no limits imposed
> on the name length other than MAX_PATHLEN.
>
> Can anyone see a reason to keep this (len > 45) check?
Yes, it was a mis-conversion done with commit 2718ff0.
The data this part (and the caller) is dealing with are
peek-remote output (40-byte hex object name, tab and
"refs/..."). Before that commit we had a check like this:
+ if (ignore_funny && 45 < len && !memcmp(name, "refs/", 5) &&
+ check_ref_format(name + 5))
+ continue;
That is, "if we are ignoring funny fake refs, continue when the
name begins with refs/ and is magic (e.g. refs/heads/master^{});
by the way that can only happen if the entire line length is
more than 45 bytes (because of 40-byte hex plus tab, anything
shorter than that cannot even fit "refs/" at the beginning of
the name).
But when the check_ref() function was written it was made to
take the name length as "len", so I do not think there is a
reason to check the name against 45 at all. Also the direction
of the comparison is wrong in the new code. It was meant to be
"line must be at least this long otherwise it is not right".
I think you can just drop "len > 45 || " part.
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