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Re: [webkit-dev] Feature Announcement: Adding
</span></a></span> </h1> <p class="darkgray font13"> <span class="sender pipe"><a href="/search?l=webkit-dev@lists.webkit.org&q=from:%22Adam+Barth%22" rel="nofollow"><span itemprop="author" itemscope itemtype="http://schema.org/Person"><span itemprop="name">Adam Barth</span></span></a></span> <span class="date"><a href="/search?l=webkit-dev@lists.webkit.org&q=date:20120502" rel="nofollow">Wed, 02 May 2012 13:03:55 -0700</a></span> </p> </div> <div itemprop="articleBody" class="msgBody"> <!--X-Body-of-Message--> <pre>On Wed, May 2, 2012 at 12:11 PM, Maciej Stachowiak <m...@apple.com> wrote: > On May 2, 2012, at 11:48 AM, Jarred Nicholls <jar...@webkit.org> wrote: > On Wed, May 2, 2012 at 2:03 PM, Maciej Stachowiak <m...@apple.com> wrote: >> On May 2, 2012, at 6:14 AM, Jarred Nicholls <jar...@webkit.org> wrote: >> On Tue, May 1, 2012 at 7:39 PM, Maciej Stachowiak <m...@apple.com> wrote: >>> I'm not too picky about how it's done, but I'd feel more comfortable with >>> #ifdef protecting the code changes rather than if(). If the changes are so >>> entangled that it's not easy to put only the changes in an ifdef, then I >>> would be skeptical that they actually have no possible effect on the >>> non-seamless case. >> >> Do we not have sufficient tests to lend us more confidence in this area? >> >> There's no amount of automated testing that would make me comfortable with >> landing a major feature today and shipping it to customers tomorrow >> (exaggerated case, but this is the kind of thing we're talking about). > > > I wholeheartedly agree, and agree #ifdefs provide safety in this regard. > > I was speaking more towards the skepticism that the runtime conditional > checks were not adversely affecting the non-seamless case. I would hope to > think that our automated tests were (or will be) abundant and thorough > enough to prove with some level of confidence that what Adam suggests would > work. If that isn't the outcome, then one could argue tests are worthless > in all situations. > > > I'm not necessarily automatically skeptical. I see two possible cases: > > 1) Code relevant to the feature is entangled with many parts of existing > code ==> greater probability of error ==> more value to #ifdefs > 2) Code relevant to the feature well isolated ==> #ifdefs should be few in > number and easy to place ==> lower cost to #ifdefs > > I don't know what the case against thoroughly deploying #ifdefs is, so I'm > not sure which of these applies. And maybe I made a mistake and these > possibilities are not exhaustive. > > #ifdefs are valuable and necessary for the reasons you stated, particularly > security and bugs in new exposed features. These things ought to be > gradually exposed, starting with explicit opt-ins. But, aside from that and > as a separate issue really, I would hope to think that our tests properly > mitigate concern for regressions on code that is being modified. > > > I have already explained why I think automated regression tests are not > sufficient risk mitigation for nontrivial new features by themselves, > namely, they have not been sufficient in the past. See for example the HTML5 > parser, which was awesome but needed significant bake time to flush out the > site compatibility regressions and other bugs. > > But I would look at it another way: #ifdef is our usual approach to making > it possible to turn off new code that needs bake time. Folks are welcome to > propose something other than the usual in specific cases. But there should > be a positive reason given why a different approach is better. Do you know > of a specific reason why #ifdefs are not appropriate in this case?</pre><pre> One example from this case is seamless navigation. I implemented seamless navigation in two steps: 1) Refactoring the existing codepaths to go through a common function. 2) Teaching the common function how to redirect navigation for seamless iframes (e.g., hyperlinks inside a seamless iframe navigate the parent frame). Step (1) is hard to protect with ifdefs whereas step (2) is easy. Fortunately, in this specific case, we landed step (1) a while ago, so it's had some time to bake already. Adam > P.S. I have in the past had the personal joy of adding back #ifdefs around a > feature that had been prematurely enabled unconditionally because it was > insufficient quality to ship. This is part of why I'm touchy about the idea > of landing significant new features with no ifdefs. I think we should try to > avoid that sort of thing and make it feasible to ship something close to > WebKit trunk at any given time, without need for lengthy branching or > extensive modifications. > _______________________________________________ webkit-dev mailing list webkit-dev@lists.webkit.org <a rel="nofollow" href="http://lists.webkit.org/mailman/listinfo.cgi/webkit-dev">http://lists.webkit.org/mailman/listinfo.cgi/webkit-dev</a> </pre> </div> <div class="msgButtons margintopdouble"> <ul class="overflow"> <li class="msgButtonItems"><a class="button buttonleft " accesskey="p" href="msg18969.html">Previous message</a></li> <li class="msgButtonItems textaligncenter"><a class="button" accesskey="c" href="thrd2.html#18970">View by thread</a></li> <li class="msgButtonItems textaligncenter"><a class="button" accesskey="i" href="maillist.html#18970">View by date</a></li> <li class="msgButtonItems textalignright"><a class="button buttonright " accesskey="n" href="msg18971.html">Next message</a></li> </ul> </div> <a name="tslice"></a> <div class="tSliceList margintopdouble"> <ul class="icons monospace"> <li class="icons-email"><span class="subject"><a href="msg18955.html">Re: [webkit-dev] Feature Announcement: Adding <iframe...</a></span> <span class="sender italic">Maciej Stachowiak</span></li> <li><ul> <li class="icons-email"><span class="subject"><a href="msg18956.html">Re: [webkit-dev] Feature Announcement: Adding <i...</a></span> <span class="sender italic">Dimitri Glazkov</span></li> <li class="icons-email"><span class="subject"><a href="msg18957.html">Re: [webkit-dev] Feature Announcement: Adding <i...</a></span> <span class="sender italic">Eric Seidel</span></li> <li class="icons-email"><span class="subject"><a href="msg18958.html">Re: [webkit-dev] Feature Announcement: Adding <i...</a></span> <span class="sender italic">Maciej Stachowiak</span></li> <li class="icons-email"><span class="subject"><a href="msg18959.html">Re: [webkit-dev] Feature Announcement: Adding <i...</a></span> <span class="sender italic">Adam Barth</span></li> <li class="icons-email"><span class="subject"><a href="msg18960.html">Re: [webkit-dev] Feature Announcement: Adding <i...</a></span> <span class="sender italic">Maciej Stachowiak</span></li> <li class="icons-email"><span class="subject"><a href="msg18963.html">Re: [webkit-dev] Feature Announcement: Adding <i...</a></span> <span class="sender italic">Jarred Nicholls</span></li> <li class="icons-email"><span class="subject"><a href="msg18967.html">Re: [webkit-dev] Feature Announcement: Adding <i...</a></span> <span class="sender italic">Maciej Stachowiak</span></li> <li class="icons-email"><span class="subject"><a href="msg18968.html">Re: [webkit-dev] Feature Announcement: Adding <i...</a></span> <span class="sender italic">Jarred Nicholls</span></li> <li class="icons-email"><span class="subject"><a href="msg18969.html">Re: [webkit-dev] Feature Announcement: Adding <i...</a></span> <span class="sender italic">Maciej Stachowiak</span></li> <li class="icons-email tSliceCur"><span class="subject">Re: [webkit-dev] Feature Announcement: Adding <i...</span> <span class="sender italic">Adam Barth</span></li> <li class="icons-email"><span class="subject"><a href="msg18971.html">Re: [webkit-dev] Feature Announcement: Adding <i...</a></span> <span class="sender italic">Maciej Stachowiak</span></li> </ul> </ul> </ul> </ul> </ul> </ul> </ul> </ul> </div> <div class="overflow msgActions margintopdouble"> <div class="msgReply" > <h2> Reply via email to </h2> <form method="POST" action="/mailto.php"> <input type="hidden" name="subject" value="Re: [webkit-dev] Feature Announcement: Adding <iframe seamless>"> <input type="hidden" name="msgid" value="CAJE5ia8ieQJR103TewCwsQ6UUXnff_0z-jGwxrHMXLoov+SuSg@mail.gmail.com"> <input type="hidden" name="relpath" value="webkit-dev@lists.webkit.org/msg18970.html"> <input type="submit" value=" Adam Barth "> </form> </div> </div> </div> <div class="aside" role="complementary"> <div class="logo"> <a href="/"><img src="/logo.png" width=247 height=88 alt="The Mail Archive"></a> </div> <form class="overflow" action="/search" method="get"> <input type="hidden" name="l" value="webkit-dev@lists.webkit.org"> <label class="hidden" for="q">Search the site</label> <input class="submittext" type="text" id="q" name="q" placeholder="Search webkit-dev"> <input class="submitbutton" name="submit" type="image" src="/submit.png" alt="Submit"> </form> <div class="nav margintop" id="nav" role="navigation"> <ul class="icons font16"> <li class="icons-home"><a href="/">The Mail Archive home</a></li> <li class="icons-list"><a href="/webkit-dev@lists.webkit.org/">webkit-dev - 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