17514 2012-06-16 14:28:21 +0000 URI token should be agnostic to escaping the characters 'u', 'r', 'l' (reopening of Issue 23) 2013-01-14 18:21:12 +0000 1 1 1 Unclassified CSS CSS Level 2 unspecified All Windows 3.1 NEW P2 normal --- 1 antonsforums bert public-css-bugzilla oldest_to_newest 69147 0 antonsforums 2012-06-16 14:28:21 +0000 4.1.1 (Tokenization) defines the URI token as: # URI url\({w}{string}{w}\) # |url\({w}([!#$%&*-\[\]-~]|{nonascii}|{escape})*{w}\) (and similarly for BAD_URI), whilst G.1 gives: # "url("{w}{string}{w}")" {return URI;} # "url("{w}{url}{w}")" {return URI;} (and similarly for BAD_URI). This means that if you escape any of the characters 'u', 'r', 'l' in a property value intended to match the <uri> value type, then what you might have expected to have tokenized as URI is actually tokenized as FUNCTION. However, this doesn't match UAs; Trident, Gecko and Presto all allow the characters to be escaped and still invoke the normal URI token parsing. The spec should be changed to match reality. Conversation begins: Bug report: http://lists.w3.org/Archives/Public/www-style/2012May/0327.html 69148 1 antonsforums 2012-06-16 15:15:32 +0000 This issue has an interesting history. It began life as Issue 23 [http://wiki.csswg.org/spec/css2.1#issue-23]: URL http://lists.w3.org/Archives/Public/www-style/2007Dec/0215.html Summary “url(” needs to be {u}{r}{l}”(” in grammar Resolution Assumed editorial. Status Closed. Testcases uri-015 It was implemented in the 2009-04-23 CR as Change 5.89 [http://www.w3.org/TR/CSS21/changes.html#q376]: C.5.89 Section G.2 Lexical scanner [2008-03-05] Change the tokenizer rules from "url("{w}{string}{w}")" {return URI;} "url("{w}{url}{w}")" {return URI;} to {U}{R}{L}"("{w}{string}{w}")" {return URI;} {U}{R}{L}"("{w}{url}{w}")" {return URI;} Unfortunately, this change only happened in G.2, rather than uniformly across both G.2 and 4.1.1, as observed by Bjoern Hoehrman in http://lists.w3.org/Archives/Public/www-style/2010Jul/0499 . This led to the change being reversed in the 2011-04-12 PR as Change 8.52 [http://www.w3.org/TR/CSS21/changes.html#q546]: C.8.52 G.2 Lexical scanner The tokenizer in the appendix allowed backslashes in the URI token, in contradiction with the same token in the core grammar and the error recovery token {baduri}: Change from {U}{R}{L}"("{w}{string}{w}")" {return URI;} {U}{R}{L}"("{w}{url}{w}")" {return URI;} to "url("{w}{string}{w}")" {return URI;} "url("{w}{url}{w}")" {return URI;} (Note that the Change description mentions an incompatiblity with the BAD_URI token, which is rather disingenuous given that this token was first introduced at the same time as the Change.) This led to a discussion (starting at http://lists.w3.org/Archives/Public/www-style/2011Apr/0680.html ) concerning the validity of a particular test case in the test suite. The issue was noted in http://lists.w3.org/Archives/Public/www-style/2012Apr/0152 to have an impact on the attr() function from css3-values. 81347 2 antonsforums 2013-01-14 18:21:12 +0000 The WG resolved[1] to permit escaping of the letters 'u', 'r' and 'l' at the start of the URI token (and implicitly resolved to do the same for BAD_URI). [1] http://lists.w3.org/Archives/Public/www-style/2013Jan/0080.html