cookie-less session + redirect => crashy crash

[vegashacker]

Reproduction:

(0) Remove any cookies from your browser that you already have for localhost (or whatever host you are running your app on).

(1) Create a page in your main.scm like this:

(define-session-page (index-page req sesh)
  (redirect-to "http://google.com"))

(2) ./script/start and hit http://localhost:8765

Kaboom with a "Page not found" and this unintelligible spew:

write-xml-content: received #<response/full>

 === context ===
/Applications/PLT Scheme v4.1.0.3/collects/xml/private/writer.ss:86:6: write-xml-content
/Applications/PLT Scheme v4.1.0.3/collects/xml/private/xexpr.ss:212:6: xexpr->string
/Applications/PLT Scheme v4.1.0.3/collects/scheme/list.ss:263:2: append-map
core
...r/private/servlet.ss:31:19
...r/private/servlet.ss:31:19
[snip]

[vegashacker]

What's going on here? We are specifying that a session is required, but since the browser has no cookie holding the session id, the response is created to instruct the browser to create said cookie. Meanwhile, the body of our page is a call ro redirect-to, which itself creates a full/response. The page code doesn't handle the situation well when it's trying to construct a response when the "content" is already a response.

[vegashacker]

Just added a patch to the git repo to provide a slightly better error message in this case (I used contracts to do this). Here's the new error message:

(planet "session.scm" ("vegashacker" "leftparen.plt" 3 0)) broke the contract
  (->*
   ((not/c any-responses?))
   (#:extras list? #:type bytes?)
   response?)
 on list-response; expected <(not/c any-responses?)>, given: (#<response/full>)

Here's the patch:
 http://github.com/vegashacker/leftparen/commit/78e2babbf42e1f87a8379590b6b90278d1780d1d

[vegashacker]

I've now fixed this on the git repo, so it'll be part of the next PLaneT release.

Here's the patch:  http://github.com/vegashacker/leftparen/commit/e72e3be38c637abfdc0300956e88bec1825ca1a9

[vegashacker]

LeftParen? 0.4 (version (3 0) on PLaneT) is out, and this bug is fixed in it.