thoughts on calculus and regression window finding

by jasonyeo

Recently, I have encountered a bug on my build of thunderbird (Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:9.0a1) Gecko/20110827 Thunderbird/9.0a1). When composing messages in the mail composer in the previous versions, I am supposed to get helpful attachment reminders at the bottom of the mail composer screen when I type keywords such as “attached”, “attachment” or “enclosed”. Somehow, the build that I was working on doesn’t trigger the reminders. Here’s a screen shot from my build:

Here’s a screenshot from the thunderbird official release (Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:6.0) Gecko/20110812 Thunderbird/6.0):

The email is the same but on the official release the attachment reminder is triggered.

Immediately, I went to the http://ftp.mozilla.org/pub/mozilla.org/thunderbird/nightly/ page to find which build caused the failure. I started with the 060111 .dmg build. Interestingly it worked. Using what I’ve learned it calculus, the bisection method, I estimated the midpoint of the dates between my 082711 build and the 060111 build I downloaded the midpoint date build (somewhere around early July). I repeated the steps to find between which build did it fail.

Here’s my result:

works:
072511 (20110725130256) Build identifier: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:8.0a1) Gecko/20110725
Thunderbird/8.0a1

fails:
072611 (20110726030439) Build identifier: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:8.0a1) Gecko/20110726
Thunderbird/8.0a1

I guess I’m gonna take on this bug by printing dump() messages all around the code to debug this guy. Not to forget, I have posted the bug on bugzilla:
Bug 683796 – Attachment keywords doesn’t trigger attachment reminder

 

By the way, I have finished bug 614407. Here’s how it looks like:

I have sent the patch for review but Blake is still looking for better suggestions on how to explain what the field does. Meanwhile I have posted on my wall on facebook to ask for suggestions. Hope it all goes well.

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