109792 2013-02-14 01:22:18 -0800 Vector<T, inlineCapacity>::data() with size 0, returns null when inlineCapacity=0 and !null otherwise 2022-08-06 14:22:06 -0700 1 1 1 Unclassified WebKit New Bugs 528+ (Nightly build) Unspecified Unspecified RESOLVED LATER P2 Normal --- 1 eric benjamin abarth ahmad.saleem792 andersca ap benjamin bfulgham darin mjs rniwa tonyg oldest_to_newest 832828 0 eric 2013-02-14 01:22:18 -0800 Vector<T, inlineCapacity>::data() with size 0, returns null when inlineCapacity=0 and !null otherwise This is inconsistent, and causes confusion when converting Vector<UChar> to Strings. See bug 109784 832831 1 eric 2013-02-14 01:30:29 -0800 This should be relatively easy to solve, we just have to be more careful to set m_buffer to 0 in the inlineCapacity case when size == 0. 832835 2 eric 2013-02-14 01:31:55 -0800 Of course, once we fix this, we may need to fix bug 109784 in a different way for the threaded parser, but that's easy to do. :) 832857 3 mjs 2013-02-14 01:46:42 -0800 What do you think the correct behavior should be, always null or never null? 832860 4 benjamin 2013-02-14 01:49:28 -0800 (In reply to comment #3) > What do you think the correct behavior should be, always null or never null? I think undefined behavior could be okay, but always null would be more useful in practice. 832865 5 mjs 2013-02-14 02:02:43 -0800 Looking at bug 109784, it seems to me that the right behavior for creating a String from an empty Vector is to get an empty string, not a null string. I am not sure if that has implications for this Vector issue. Originally the design intent of Vector was that you should not rely on data() when length() is 0. Making data() be always null is possible, but taking a quick look at the code, it would add extra branches to a number of VectorBase methods for the non-inline case (or else a branch in data() itself). 832868 6 benjamin 2013-02-14 02:10:12 -0800 (In reply to comment #5) > Looking at bug 109784, it seems to me that the right behavior for creating a String from an empty Vector is to get an empty string, not a null string. I am not sure if that has implications for this Vector issue. I made a comment on that bug regarding that. > Originally the design intent of Vector was that you should not rely on data() when length() is 0. > > Making data() be always null is possible, but taking a quick look at the code, it would add extra branches to a number of VectorBase methods for the non-inline case (or else a branch in data() itself). Does making it null in debug sounds like an acceptable compromise to you? I would prefer it if people could not rely on that behavior, like in the case of Vector->String. 834631 7 188691 benjamin 2013-02-15 21:47:41 -0800 Created attachment 188691 Patch 834632 8 benjamin 2013-02-15 21:49:04 -0800 Quick stab at it, it probably does not compile. I think we may be able to make the change while reducing the number of branches. 1889371 9 ahmad.saleem792 2022-08-06 06:50:35 -0700 I can still see references to this in the Webkit Github source e.g.: https://github.com/WebKit/WebKit/blob/f407fbb287465a0ff68442eb7297862518e211cc/Source/WTF/wtf/Vector.h#L427 I think this patch need to rebased to land. Appreciate if someone is willing to work else I think we can mark this as "RESOLVED LATER". Thanks! 1889404 10 rniwa 2022-08-06 14:22:06 -0700 Later. 188691 2013-02-15 21:47:41 -0800 2013-02-15 21:47:41 -0800 Patch bug-109792-20130215214407.patch text/plain 5310 benjamin U3VidmVyc2lvbiBSZXZpc2lvbjogMTQzMDUxCmRpZmYgLS1naXQgYS9Tb3VyY2UvV1RGL0NoYW5n ZUxvZyBiL1NvdXJjZS9XVEYvQ2hhbmdlTG9nCmluZGV4IDA4YjM2Nzg3NjAxOTgyMDU5NTlkNWVk ZWE3NjJiZTAxNjdiMTA5NGMuLmFlYmE3MTFlZmI3MWQ5MzJkZGVhMWM1NThmNGQyZjcxZDYxMjQz ZmIgMTAwNjQ0Ci0tLSBhL1NvdXJjZS9XVEYvQ2hhbmdlTG9nCisrKyBiL1NvdXJjZS9XVEYvQ2hh bmdlTG9nCkBAIC0xLDMgKzEsMjIgQEAKKzIwMTMtMDItMTUgIEJlbmphbWluIFBvdWxhaW4gIDxi ZW5qYW1pbkB3ZWJraXQub3JnPgorCisgICAgICAgIFZlY3RvcjxULCBpbmxpbmVDYXBhY2l0eT46 OmRhdGEoKSB3aXRoIHNpemUgMCwgcmV0dXJucyBudWxsIHdoZW4gaW5saW5lQ2FwYWNpdHk9MCBh bmQgIW51bGwgb3RoZXJ3aXNlCisgICAgICAgIGh0dHBzOi8vYnVncy53ZWJraXQub3JnL3Nob3df YnVnLmNnaT9pZD0xMDk3OTIKKworICAgICAgICBSZXZpZXdlZCBieSBOT0JPRFkgKE9PUFMhKS4K KworICAgICAgICBXb3JrIGluIHByb2dyZXNzLgorCisgICAgICAgICogd3RmL1NlZ21lbnRlZFZl 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