Interesting
A Pivot noted a facepalm + headdesk moment when debugging an issue whose cause turned out to be related to two adjacent string literals being auto-concatenated by Ruby's parser.
>> "foo" "bar" => "foobar"
In this case, a missing comma in a method call went undetected because of this language characteristic. Whether or not this follows the principle of least surprise is an exercise left up to the reader.
Another pair warned that while this is valid syntax in Ruby 1.8.7 and beyond:
define_method(:burninate) { |&block| block.call("burninating") }
.. in 1.8.6 you can't use a block as a parameter of a block.
Another pair noted that exceptions with Sunspot can cause wider failures on a site than just those that touch Solr. The symptom on this project was that if Solr was inaccessible for any reason every page on the site would throw an error. Their fix was to use Sunspot's SessionProxy to wrap methods with some exception handling love.
Lastly, GoRuCo -- the Gotham Ruby Conference -- will be held on May 22nd at Pace University's downtown campus. The roster of talks is up and registration is open for business.
Help
Does anybody have any good techniques for dealing with STDOUT/STDERR and exception handling when shelling out in Ruby on Windows?
Nobody did. Do you? Please share in the comments.
Interesting
A pair ran system updates on their Snow Leopard box which caused bunch of test failures in their project. Most of the failures were occurring around the parts of the application that used BigDecimal. After digging they found:
>> BigDecimal.new("1.01").to_f
=> 1.1
Oops! Looks like Apple shipped Ruby 1.8.7 p173 with a recent update. p173 has a bug that some dude introduced into BigDecimal. The fix was to update to p174 which was released quickly after this was discovered.
While on the subject, BigDecimal is kind of a drag. Its #inspect output is inhumane and new'ing up BigDecimal objects requires an ugly call to its constructor. A Pivot recommended using the undocumented bigdecimal/util which adds a convenience method to Float for creating new BigDecimals:
>> require 'bigdecimal/util'
>> 3.14159265.to_d
=> #<BigDecimal:10056bea8,'0.314159265E1',12(16)>
And a nickel's worth of free advice?
>> BigDecimal.send :alias_method, :inspect, :to_s
>> 98.6.to_d
=> 0.986E2
Unless you prefer:
#<BigDecimal:101137c78,'0.986E2',8(8)>
Spring is just around the corner, and it has been a beautiful week here in sunny NYC. We've learned a lot this week, as you'll see as we do the Round-up!
Ask For Help
- Kevin and I are having a heck of a time using Web Driver to drive an app that uses Google Maps. Whenever we click on or type into anything displayed on the map, the contents of the map (including the Google logo and the zoom control) move about 20 pixels up. Our tests seem to still work, it just looks like it's broken. Anyone else seen this or know what might cause it?
Interesting Things
Kevin and I discovered that Capybara's
page.execute_scriptdoesn't like to execute multiple statements. It really wants to evaluate a single expression. The upside of this is that it's really good at casting Javascript values into Ruby; it seems to work well with strings, numbers, and even arrays. If you really want to execute multiple statements, you can do this:page.execute_script <<-JS (function(){ statement1(); statement2(); return someValue; })() JSTodd found out the hard way that Ruby's
String#sprintf(also seen as theString#%) will cast your string numbers to octal if you're not careful. Behold:>> "%d" % "010" => "8" >> "%d" % "08" ArgumentError: invalid value for Integer: "08" from (irb):2:in `%' from (irb):2Make sure you don't feed
sprintfa string number that starts with a0unless you mean it to be octal.Rachel tells us that there's an upcoming Rails workshop for women in NYC. Rumor has it that Pivotal's own Sarah Mei is behind it. She's been known to do such things before. Details as they become available.
Pat's improv show is tonight! Check him out at the Magnet Theater.
Spring is in the air here in sunny NYC! Well, it was sunny for a bit. Now it's turned into that classic film-noir drizzle. That's authentic New York weather outside our window as we do the Round Up!
Ask for Help
I asked, "In Jasmine, how do you spy on a constructor?" Suppose you have a constructor called
Widget. SayingspyOn(window, "Widget")swaps out the realWidgetfunction with a spy. The realWidgetimplementation takes its prototype with it, which means that Widgets created while the constructor is spied on don't get the methods aWidgetwould get. That's true even when you spy withspyOn(window, "Widget").andCallThrough().Also, there doesn't seem to be a way to stub out object construction and return an object of your choosing. In Rspec in Ruby you can say,
Widget.should_receive(:new).and_return(my_fake_widget)
because
.newis a class method. But in Javascript,newis a keyword which always creates a new object. I'm guessing there's no good way around this, but if there is one, we could really use it.Update: This is, as it turns out, entirely incorrect. Jasmine's
.andReturn()does let you stub constructors properly. I still have no idea how this works. See the comments for more discussion.
Interesting Stuff
Todd notifies us that in ActiveRecord, dynamic finders with too-few arguments fail silently. That is, if you say,
Person.find_by_first_name_and_last_name_and_email("Todd", "Persen")
and fail to specify a value for
email, the value is taken to benil. That means that the finder will look for someone named "Todd Persen" with anilemail address. You might have meant that. More likely, you made a mistake. AR should probably check the number of arguments it's given against the number of columns in the finder name.You already know that Pivotal does real Extreme Programming. But did you know that we have...Extreme Breakfast?
It's been a quiet week in New York City, my hometown. Let's do the round-up.
Ask for Help
Ian Z. asked, "Given a
<select>input element, how do I select an option by its name and not its value using jQuery?"The answer? You can't. Or you couldn't. But the very act of observation changes the phenomenon which is observed), and by lunch, you could. Pat's just crazy like that.
$.fn.chooseis available in chewable Gist form.
And that's it. I'll see you back here next week.
Live from the set of Snowpocalypse 4: The Reckoning, it's the weekly NYC Standup Round-up!
Interesting
Corey points out that the Google Maps embed code wants to be put directly on a page, not loaded on demand with something like jQuery's
$.getScript(). Luckily, there's a fix: adding anasync=2param to the Google Maps API URL. More info in a post from Olly Hodgson.Rachel and Pat found out the hard way that Bundler 0.9.8 doesn't run on Ruby 1.8.6. Upgrade your Ruby or stick to Bundler 0.9.7.
The same team had a real headache even upgrading from Bundler 0.7.0 to 0.9.8. The gem cache directory moves and the Gemfile format changes, among other things. This sounds like more than a minor-version change to your standup scribe.
Don't put Coca-Cola in the freezer. I know, you want it to get cold faster. You'll come back for them in like five minutes. It seems like a great idea. But out of sight, out of mind, and the next day, you open the freezer to grab your microwave burrito and you find these waiting to explode all over you:
I'm just asking you to think this through. Do you want frozen Coke foam splattered across your nice shirt? You can put an end to this madness. Just don't do it.
Points of Interest
Following a recipe from Dan Chak's Enterprise Rails, we came across code following this pattern:
class Thing def foo def bar(args) # some code end # some code that calls bar() end endThe structure of this code suggests that
baris scoped only within the context offoo. But alas, that is not the case. Ruby simply definesThing#barthe first timefoois called, analogous todefine_method :bar. Misleading syntax, for sure.Ryan Davis's Flay is awesome. If you're not familiar with it, Flay parses your Ruby and compares subtrees with each other to find where code has been duplicated (or nearly so). Run on a codebase of over 20,000 lines of Ruby, Flay was able to quickly indicate places where we had duplicate code lying around, as well as many likely targets for refactoring work. We've found it to be helpful in keeping code DRY.
This looks interesting: MagicPrefs gives you gestures for your Magic Mouse (Yes, Pivotal NYC has Magic Mice, as well as 27" iMacs. Apply today!).
In Snow Leopard, mapping CapsLock => Ctrl when two keyboards are plugged in is problematic. You can do it by plugging in one keyboard at a time and mapping each one individually. If anyone knows the story behind why this is, or how to deal more easily, please comment!
Another interesting link: Open Frameworks is a "creative coding" toolkit (like Processing) that's implemented in C++. Why ask why?
Another lesson learned the hard way: starting up a bunch of leopard machines at the same time wreaks havoc on the network for a few minutes. Packet storm, dropped packets, etc. Is Bonjour to blame? Inquiring minds want to know.
If you're trying to stub a subclass of
ActionMailer::Basewith Double Ruby (also known as RR), and you're having issues, try stubbing the method onActionMailer::Basedirectly. There's some weirdness there withmethod_missingin Rails 2.3.
Help Wanted
Does anyone know how to make
command-1throughcommand-9switch tabs inside ofTerm.app? By default, these keys are bound to switching windows, and we'd love to be able to do this on tabs instead.Rails's
select_tag(..., :multiple => true)option doesn't properly setselectedon the generated options. This appears to be a boog, and anyone who's interested in helping a Pivot write a patch, please comment below!
Happy Holidays from NYC!
Interesting
- Someone noticed that rspec's
should_not(rdocs here) returns false when the spec passes, whereasshouldreturns true when it passes. This has unexpected results when ashould_notis used within a Webratwait_forloop (code here) -- wait_for loops until its body returns true. Fail! - John Resig has implemented a
jQuery.requiremethod that should be in the next release. Check out the commit and the lengthy discussion here. Everyone's a critic. - One Pivotal project that recently switched from MySQL to Postgres noticed that PG sorts NULL values differently than MySQL. The default in PG is NULLS FIRST when ordering DESC, and NULLS LAST otherwise. You can override this behavior by using a NULLS FIRST or NULLS LAST clause in your ORDER BY.
- Someone was reminded the hard way that Ruby's
rescue, by default, only catches exceptions inherited from StandardError.
Help
- Does anyone know of a service or library that will convert an email into a tracker story? The use case is stake holders who send UI/UX requirements within emails with attachments, etc.
Interesting
>> false.blank?
=> true
blank? first checks to see if a method responds to empty? and if not evaluates !self which in false's case will always be true. This caused a pair a bit of confusion when trying to validate the completeness of a form that had a checkbox.
Railscamp — an all-weekend hackfest — is being held in Rhode Island in March of next year.
All API keys were recently reset on Gemcutter due to a security bugfix - in order to publish gems you'll need to update your gemcutter gem to regenerate your key.
Postgres will return an error if you attempt to ORDER BY columns that are not specified in the SELECT. This is painful in cases where you're using DISTINCT with any kind of JOIN.
One team cut their deployment down from 7 minutes to 30 seconds with a few cap recipe tweaks. Most of the time was saved by symlinking gem bundler-related directories to prevent bundler from building native gems on each deploy and by only running database migrations when anything in db/migrate had changed.
When using the inherited hook for ActiveRecord::Base, beware of tables that have their name overriden by set_table_name. The inherited hook will execute prior to that statement being evaluated which can cause strange results.
Getting Selenium to work with Snow Leopard involves some manual file renaming hackery — for anybody struggling with this there are a couple of posts out there to walk you through the process.
Help
RubyMine and gem bundler don't seem to get along - RubyMine complains that bundled gems aren't attached but these gems aren't available when we try to attach them. Any ideas?
RubyMine uses your gem path so you'll be able to attach to the gem if you add your gem bundler path to your ~/.gemrc file
There's an option to disable this nagging alert in the preferences.
Is there a good Rails plugin skeleton/template out there?
Know of one? Let us know in the comments.
Interesting
Don't use sleep 1 or such in before blocks in rspec if you need to ensure a delay between two events. A before block is ran between all nested contexts so you're probably incurring a larger penalty. Instead, you should stub Time.now.
One team implemented git commit hooks to facilitate communication - on rebase or merge new messages from a text file in the project root are displayed to alert other pairs to changes such as gem upgrades, noteworthy database changes, etc.