#5274 better error messages when incorrect regexp is passed to constraints in routes - Ruby on Rails

State changed from new to invalid
Importance changed from to Low

According to the docs you can use normal regexp's with the start/end markes: http://guides.rubyonrails.org/routing.html#specifying-constraints

Am I missing something? Maybe this was fixed along the way. I'm closing the ticket, however if this is still an issue just leave a comment with steps to reproduce the problem, or a patch and I'll reopen.

October 7th, 2010 @ 06:38 AM

Jakub Suder

Well, the guide you linked to shows examples with regexps without start/end markers...

Example from that link:

constraints(:id => /[A-Z][A-Z][0-9]+/) do

And if you do this:

constraints(:id => /^[A-Z][A-Z][0-9]+$/) do

you get a confusing error and you waste half an hour trying to figure out what may be wrong (it's not just me, someone else from my team had this last week too). This happens on Rails 3.0.0 final, I'm not sure about latest development version.

October 7th, 2010 @ 07:51 PM

Rohit Arondekar

State changed from invalid to open
Assigned user set to Andrew White

Sorry for that!

Well I think I've seen something similar. And iirc, it's not possible/easy to allow use of start/end markers in constraints.

Assigning to Andrew for clarification.

October 8th, 2010 @ 02:07 AM

Andrew White

Milestone cleared.

There's a commit on master which raises an ArgumentError when an anchor is used in a constraint:
http://github.com/rails/rails/commit/ca3936dbd691538d97d8dbe2bc1d64...

It's impossible to add anchor support to routing constraints since each regexp is assembled into a larger regexp with it's own anchors. Validations are different because there you are specifying the whole regexp rather than just a fragment so it's perfectly valid that you might want to use an anchor.

I'll backport the above commit to the 3-0-stable branch - I believe something similar already exists in the 2-3-stable branch.

October 8th, 2010 @ 07:02 AM