Re: [PATCH] Introduce a filter-path argument to git-daemon, for doing custom path transformations

Hi,

On Thu, 19 Mar 2009, Johan Sørensen wrote:

2009/3/19 Johannes Schindelin [off-list ref]:

quoted

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I actually was hoping (especially we have Dscho on Cc: list) that 
somebody like you would start suggesting a "plug in" approach to load 
.so files, which would lead to a easy-to-port dso support with the 
help from msysgit folks we can use later in other parts of the system 
(e.g. customizable filters used for diff textconv, clean/smudge, 
etc.)

I do not like that at all.  Dynamic libraries -- especially on Windows 
-- are a major hassle.

However, I cannot think of anything Johan might want to do that would 
not be possible using a bunch of regular expressions together with 
substitions.

Let me reiterate my use-case then: I need to dynamically substitute one 
path with another. Perhaps "map" paints a better picture than 
"substitute" here. Please refer to my second mail in this thread for 
more details.

The only way I can see regexps work, is that if they're read, on a 
per-request basis (reloading git-daemon every time they change is just 
silly), from somewhere outside the git-daemon. Then, you might as well 
take the full-on approach this patch provides.

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FWIW I have experimental code in my personal tree that sports 
strbuf_regsub(), a function to replace matches of a regular expression 
(possibly with groups) by a given string (which may contain \0 .. \9, 
being replaced with the respective group's contents).

Do not get me wrong, I can see your use case.

But I have been cautioning against other possibly regrettably things, and 
it gave me _no_ pleasure at all to be proven correct in hindsight.

I'd rather be called grumpy old Git, be ridiculed and insulted, but at the 
same time have precautions in git.git that prevent having to admit 
mournfully that some change was not so brilliant after all.

So if some rules consisting of regular expressions with appropriate 
substitutions, even if they will have to be updated from time to time, 
solve your case, I'd rather have that than allow a server to run external 
programs that are not exactly well audited against all kinds of attacks.

Ciao,
Dscho