One of the open-source projects I contribute to is Fink, a package manager for OS X; if you’ve used apt-get or yum on Linux, it provides a similar facility, allowing you to install, say, GnuPG by running fink install gnupg. It installs things into its own directory tree, rooted at /sw by default, to avoid interfering with things shipped by Apple (/, /usr) or manually installed by the user (/usr/local.) That is, if you have Fink installed, your system will have /sw/bin, /sw/lib, /sw/etc, /sw/share/man, &c.

So that you can run things installed in these nonstandard locations, Fink provides some shell commands in /sw/bin/init.sh which edit environment variables like PATH and MANPATH to include the /sw/* directories. Most Fink users have . /sw/bin/init.sh in their ~/.profile, so these commands will be invoked when their shell starts.

Having my shell automatically pull in Fink at startup doesn’t work for me, though. It’s important to me to have a clean environment available. For instance, when I’m contributing to non-Fink open-source projects, trying to help someone who doesn’t have Fink installed troubleshoot something, or submitting a bug report for a program that interacts with other programs where I have the Fink version installed, but Apple ships a different version with the system.¹ (Note that this is only an issue if program A interacts with program B by invoking it as a standalone process without using an absolute path.²)

Also, as a Fink developer, I actually have multiple Fink installations at different paths,³ and I only want one loaded at a time; I don’t want to activate /Volumes/SandBox/fink/dev-sw in an environment where /Volumes/SandBox/fink/sw has already been pulled in!

It’s much easier to pull Fink stuff in later when I need it than to undo the changes that /sw/bin/init.sh makes to my environment. My solution for making it easy to activate a particular Fink installation was to add the following to ~/.bashrc:

if [ -n "$SW" ]
    then export CFLAGS="-I$SW/include"
    export LDFLAGS="-L$SW/lib"
    export CXXFLAGS="$CFLAGS"
    export CPPFLAGS="$CXXFLAGS"
    export ACLOCAL_FLAGS="-I \"$SW/share/aclocal\""
    export PKG_CONFIG_PATH="$SW/lib/pkgconfig"
    export PS1="[$SW_DISPNAME \\W@$(hostname -s)]\\\$ "
    . "$SW/bin/init.sh"
    export PATH=~/bin:"$PATH"
fi

What this does is arranges it so that if I start a new shell with SW and SW_DISPNAME set, it’ll pull in the Fink installation rooted at the directory $SW and put $SW_DISPNAME in my shell prompt so that I can see which environment I’m using. The extra environment variables before . $SW/bin/init.sh set things up so that if I compile things by hand, they’ll find and link against Fink-installed libraries; the PATH setting at the end is because init.sh places the Fink bin directory at the front of the PATH, and I want my personal bin directory to come before it.

I run the following script (saved as ~/bin/finkinit) when I want to pull in Fink:

#!/bin/bash
 
FINK=${1:-main}
 
case "$FINK" in
    main)
        SW=/Volumes/SandBox/fink/sw
        SW_DISPNAME="fink"
        ;;
    dev)
        SW=/Volumes/SandBox/fink/dev-sw
        SW_DISPNAME="fink-dev"
        ;;
    *) echo "Unknown fink install '$FINK'" >&2 ; exit 1
esac
 
export SW SW_DISPNAME
exec /bin/bash

This gives me a subshell with Fink turned on, which I can exit out of when I want to return to a clean environment. If I run it as finkinit, I get my main Fink installation, or I can run finkinit dev to get an alternate Fink.

While working with a large codebase, I often want to find the origin of a particular line. Subversion offers a tool, annotate (aka blame, aka praise), which displays the author and revision for every line in a file, indicating who made the last change to a line. However, the last change is often not very useful; it was a minor change as a result of some other change you’re not interested in, or the code was moved around due to refactoring, and you need to go back even further.

When I need to do this, I find myself doing a sequence of:

1. svn blame FILE | less; find the revision N where the line was last changed
2. svn log -rN FILE | less; if the change is interesting, read the commit log for the file
3. svn blame FILE@N-1 | less; using Subversion’s little-known pinned revision¹ syntax, find the previous time the line was changed
4. Using N-1 as the new N, return to step 2.

I’ve put together a rough version of a tool to make this easier; it’s at /trunk/blamegame in my repository, which is here for browsing with ViewVC, or it can be checked out with svn co http://zevils.com/svn/trunk/blamegame blamegame . It still needs some fine-tuning and documentation, but invoke it like blamegame FILE LINE (where FILE is a URL or the path to a file in a Subversion working copy) to start looking at a particular line of a file. You can navigate and search the file using a less-like interface. To drill down to the previous change to a line, hit r and then enter the line number. l, o, n, and m switch between viewing the commit log, the changed parts of the old file, the changed parts of the new file, and (the default) the diff. If you need to change the path you’re looking at (for instance, to jump inside a branch), use the p command. h will show the available commands.

Let me know what you think.

To keep track of people’s birthdays, I use Mac OS X’s¹ Birthday Calendar feature of Address Book/iCal. I was going through my calendar the other day, and I noticed that a birthday which I knew was sometime in January wasn’t showing up. It was on the corresponding Address Book contact, though. I deleted the birthday from this contact and reentered it, which fixed that entry, but on the suspicion that more birthdays might be missing, I flipped through my calendar and found:²

The Address Book birthday field has the misfeature that it forces a year to be specified.³ What a rude thing for Address Book to be asking! Anyway, I’d arbitrarily picked year 1⁴ for the year for any contacts whose birth years I didn’t know. Maybe, I thought, the Gregorian reform was throwing things off. However, changing the year to 1900 didn’t help matters, and in fact made them worse:

Turning the birthday calendar off (which wipes out iCal’s backing store for the calendar) and on didn’t help matters. A web search turned up some other people having the same problem, but the only useful solution they came up with was deleting and recreating entire contacts by hand.

I wanted to see if the raw data was wrong in Address Book’s database. Address Book uses Core Data in a way that makes the database difficult to work with at the SQLite command-line level, so instead I hacked /Developer/Examples/Python/PyObjC/AddressBook/Scripts/exportBook.py to emit the birthday field by adding ('Birthday', AddressBook.kABBirthdayProperty) to FIELD_NAMES and the following to encodeField:

    elif isinstance(value, AppKit.NSCalendarDate):
        return value.descriptionWithCalendarFormat_("%Y-%m-%d")

It turns out that a number of entries had negative years, e.g. -1900-03-23 instead of 1900-03-23. I’m not sure how this happened, but here’s a script to fix it:

#!/usr/bin/python
"""
Fix negative birthday years in Address Book.
This work is hereby released into the Public Domain.
"""
import AddressBook
import AppKit
 
def personName(person):
    return "%s %s" % (
        person.valueForProperty_(AddressBook.kABFirstNameProperty),
        person.valueForProperty_(AddressBook.kABLastNameProperty)
        )
 
def formatDate(date):
    return date.descriptionWithCalendarFormat_("%Y-%m-%d")
 
def fixBirthday(birthday):
    year = int(birthday.descriptionWithCalendarFormat_("%Y"))
    if year < 0:
        return birthday.dateByAddingYears_months_days_hours_minutes_seconds_(
            -year * 2, 0, 0, 0, 0, 0)
    else:
        return None
 
def fixPersonBirthday(person):
    birthdayProp = AddressBook.kABBirthdayProperty
 
    birthday = person.valueForProperty_(birthdayProp)
    if birthday == None: return
 
    fixedBirthday = fixBirthday(birthday)
    if fixedBirthday != None:
        print "Fixing up %s: %s -> %s" % (
            personName(person),
            formatDate(birthday),
            formatDate(fixedBirthday)
            )        
        person.setValue_forProperty_(fixedBirthday, birthdayProp) 
 
book = AddressBook.ABAddressBook.sharedAddressBook()
 
for person in book.people():
    fixPersonBirthday(person)
 
book.save()

I’d set up a Trac installation for wedding planning, instead of using MediaWiki (the system Wikipedia uses, which I already had a couple of installations of) since we wanted both a wiki (venue data, possible honeymoon destinations, guest lists… shut up, it’s useful!) and ticket system (useful for tracking things like thank-you notes and being able to assign specific ones to either Liz or myself).

However, Dreamhost doesn’t support mod_python, so pages were taking way too long to load. I decided to switch over to MediaWiki for the wiki part and just use my existing Bugzilla installation for ticket tracking. Hence, a new script over on the code page, trac2mw. Our wiki was fairly tiny, so caveat user. I didn’t bother having it migrate tickets tickets or attachments, since we didn’t have any data there that was worth preserving. The input format, a MySQL XML dump, probably isn’t ideal for a lot of people (since Trac runs on SQLite by default.) It does fix up the wiki page syntax (the parts of it we were using, at least), though.