Wednesday, February 6, 2008

Mercurial adventure on Widows

With a friend at work we decided to check out Mercurial as source control system. The repository was set up on a Linux box and zillion lines of code and libraries were sucked in from ClearCase, now I just had to clone it to my lap-top running Windows XP.

Installed Mercurial 0.9.5 via TortoiseHg (I am familiar with Tortoise with SVN so it was a natural choice) - very easy and straightforward so far. Issued clone command - hm, filename too long. Switching to cygwin - doesn't help.

So Ok, we have pretty deep directories structure and Mercurial makes it worse because it translates everything to lower case by "escaping" capital letters - adding underscore before the letter, so "A" becomes "_a" and a single underscore becomes a double one. Why? This is to avoid problems when working with case-insensitive operating systems like Windows. Fair enough, but what do I do with these long filenames now... Python bug? Oh, great. In the meantime the error became "file not found", but I (correctly) suspected the cause is the same.

I found this bug report (and this one) - at least it happenned to other people, it says I can use a 'usestore' workaround. Cool, found this - says change one of the scripts, but hey, they are compiled?! Ok, downloaded ActivePython (I admit, I never touched Python in my life) also downloaded the sources. But apparently I need a C compiler too for the full build from source - that's too much, I decided to just run Mercurial with the interpreter.

Found the right script, changed it. Boom, of course extra space in indentation - until now I only heard jokes about this (besides similar experience with Fortran half a life ago). Nevermind, got it now. Still not working. I take another look at the script - the if statement I just added was already there before! Oops, what's going on? Trying to understand the Python code - it is looking for some 'usestore' configuration option, which BTW is supposed to disable the "escaping". All I need now is to set it. Hm, how? Eventually I find out that I need to edit <TortoiseHg-install-dir>/Mercurial.ini adding

(If you use plain Mercurial, not Tortoise, create Mercurial.ini under <mercurial-install-dir>)

I do it and... voilĂ , the repository cloned!!! So bottom line - all I needed was ini file change. It is somewhat dangerous 'coz I still have the mixed case, but at least I have the code on my laptop. Why didn't I find it in an FAQ or tips'n'tricks or something? No idea. Hope this post helps the next person who googles for it.