Re: Why do we allowed mixed versions of libsvn_* ?

On Dec 4, 2004, at 5:15 AM, Branko Čibej wrote:
>
> But first, you'd better explain what's so horribly wrong with the
> exieting FS vtable that you have to completely rewrite it.

I don't have to completely rewrite it. I want to change the signature
of one function in the private FS vtable: begin_txn(). Specifically,
I want to add a 'flags' field, and then I want the two back-ends to
implement the new vtable func signature.

Nothing complicated here. But now I have to worry about libsvn_fs 1.1
possibly loading libsvn_fs_base 1.2 and blowing up, because our
'version checks' allow this to happen.

I see that you committed a stricter version check in libsvn_fs 1.2;
that it now refuses to load anything but a 1.2 fs back-end. I guess
that solves the problem ghudson mentioned (programmatically preventing
the mixing of library versions.)

But in general, I agree with ghudson: we've never promised users that
they can randomly mix versions of libraries. I don't want to make that
promise.

So,

   1. I'm not going to worry about fs 1.1 trying to load fs_base 1.2.
If somebody tries that and complains, our response is "don't mix
library versions".

   2. IMO, all of the version-compatibility funcs that currently exist
shouldn't be ripped out, they should be used to *enforce* equal library
versions. I think we should call svn_ver_equal() absolutely everywhere
we can. :-)

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Received on Sat Dec 4 15:32:16 2004