<html><head><style>body{font-family:Helvetica,Arial;font-size:13px}</style></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"><div id="bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px; color: rgba(0,0,0,1.0); margin: 0px; line-height: auto;">Well, I do believe the warnings that show up in Xcode come from the Swift compiler itself. In the case where you have a line</div><div id="bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px; color: rgba(0,0,0,1.0); margin: 0px; line-height: auto;"><br></div><div id="bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px; color: rgba(0,0,0,1.0); margin: 0px; line-height: auto;"><p style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;"><span style="font-variant-ligatures: no-common-ligatures; color: #31595d">test</span><span style="font-variant-ligatures: no-common-ligatures">(a: n!);</span></p></div><div id="bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px; color: rgba(0,0,0,1.0); margin: 0px; line-height: auto;"><br></div><div id="bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px; color: rgba(0,0,0,1.0); margin: 0px; line-height: auto;">then it should be trivial at least in that case to emit a warning.</div><div id="bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px; color: rgba(0,0,0,1.0); margin: 0px; line-height: auto;"><br></div><div id="bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px; color: rgba(0,0,0,1.0); margin: 0px; line-height: auto;">Apple’s radar is a no-go for me, still wating months on a segmentation fault issue with Swift 3. They just lumped them all together and closed all the issues. I opened up a new ticket the same day with reproducible scenario and haven’t heard from them. No problem though, as I’m nearly finished re-writing our code base function by function :) . That kind of thing (fixing the Fix-its) needs to come internally.</div> <br> <div class="bloop_sign" id="bloop_sign_1488859147830352128"></div> <br><p class="airmail_on">On March 6, 2017 at 10:57:04 PM, Austin Zheng (<a href="mailto:austinzheng@gmail.com">austinzheng@gmail.com</a>) wrote:</p> <blockquote type="cite" class="clean_bq"><span><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div></div><div>
<title></title>
I've worked on several large Swift codebases for large, prominent
companies and use of '!' was extremely rare and highly discouraged.
It showed up most frequently as the type for @IBOutlet properties,
which would not be relevant when programming a server application.
<div class=""><br class=""></div>
<div class="">I completely agree with you that the Xcode fix-it is
terrible and should be removed or replaced, but unfortunately it's
been made clear that changes to Xcode are outside the purview of
swift-evolution. You should definitely file a Radar, though.</div>
<div class=""><br class=""></div>
<div class="">Best,</div>
<div class="">Austin<br class="">
<div class=""><br class="">
<div>
<blockquote type="cite" class="">
<div class="">On Mar 6, 2017, at 7:52 PM, Elijah Johnson via swift-evolution <span dir="ltr" class=""><<a href="mailto:swift-evolution@swift.org" target="_blank" class="">swift-evolution@swift.org</a>></span> wrote::</div></blockquote></div></div></div></div></div></span></blockquote><blockquote type="cite" class="clean_bq"><span><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div class=""><div class=""><div><blockquote type="cite" class="">
<br class="Apple-interchange-newline">
<div class="">
<div id="bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px;" class="">Well, I think that it is far more ingrained into the
language and its daily use than you might realize.</div>
<div id="bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px;" class=""><br class=""></div>
<div id="bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px;" class="">At the very least, someone should correct the XCode
warning that says (to paraphrase) “code does not comple, double
click to insert optional here” and create some code-analysis
warnings against the practice of forced unwrap where it can be
replaced.</div>
<div id="bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px;" class=""><br class=""></div>
<div id="bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px;" class="">I’ve been a full year with Swift now, and just a week or
two ago I learned about this optional binding feature. You could
say I’m not devoted enough, but I’ve not had any crashing issues,
XCode just told me to insert force-unwrap and thats what I
did.</div>
<div id="bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px;" class=""><br class=""></div>
<div id="bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px;" class="">If this whole “force-unwrap” thing isn’t the intended way
of doing things, that could be made a bit more explicit I
think.</div>
<div id="bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px;" class=""><br class=""></div>
<div id="bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px;" class="">Here’s a screenshot of what I am referring
to: <a href="https://snag.gy/dH6twR.jpg" class="">https://snag.gy/dH6twR.jpg</a></div>
<div id="bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px;" class=""><br class=""></div>
<div id="bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px;" class="">Says: Fix it: Insert !</div>
<div id="bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px;" class="">Should say: Fix it: Use optional binding.</div>
<div id="bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px;" class=""><br class=""></div>
<div id="bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px;" class="">Xcode might not be in the Swift evolution domain, but I
think the idea of warnings for "unnecessary use of !” are.</div>
<div id="bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px;" class=""><br class=""></div>
<div id="bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px;" class="">On March 6, 2017 at 9:47:04 PM, Austin Zheng (<a href="mailto:austinzheng@gmail.com" class="">austinzheng@gmail.com</a>)
wrote:</div>
<blockquote type="cite" class="clean_bq" style="font-family: Helvetica, Arial; font-size: 13px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">
<div class="">
<div class=""></div>
<div class="">
<div dir="ltr" class=""><span class="">Swift already is an
unmanaged language, and is far closer to C++ than Java. There is no
equivalent to the CLR or JVM and it is trivially easy to call into
C code or the unsafe APIs and do nearly anything that C can do with
regard to direct access to memory.</span>
<div class=""><span class=""><br class=""></span></div>
<div class=""><span class="">The force-unwrap operator was never
intended to model a Java-style runtime exception. Instead, it is an
assertion which indicates a programmer logic error. The preferred
way to handle an optional at runtime has always been to use the
conditional-unwrapping functionality the language offers. The
correct way to report errors at runtime that aren't due to
programmer error is through the do-try-catch mechanism. Pervasive,
unnecessary use of '!' is a project management and/or developer
competence issue, and not something the language should go out of
its way to fix.</span></div>
<div class=""><span class=""><br class=""></span></div>
<div class=""><span class="">Sugaring 'if let' for programmer
convenience is something on the commonly rejected proposals
list: <a href="https://github.com/apple/swift-evolution/blob/master/commonly_proposed.md" class="">https://github.com/apple/swift-evolution/blob/master/commonly_proposed.md</a></span></div>
<div class=""><span class=""><br class=""></span></div>
<div class=""><span class="">Regards,</span></div>
<div class=""><span class="">Austin</span></div>
<div class=""><span class=""><br class=""></span></div>
</div>
<div class="gmail_extra"><span class=""><br class=""></span>
<div class="gmail_quote"><span class="">On Mon, Mar 6, 2017 at 6:27
PM, Elijah Johnson via swift-evolution<span class="Apple-converted-space"> </span><span dir="ltr" class=""><<a href="mailto:swift-evolution@swift.org" target="_blank" class="">swift-evolution@swift.org</a>></span><span class="Apple-converted-space"> </span>wrote:<br class=""></span>
<blockquote class="gmail_quote" style="margin: 0px 0px 0px 0.8ex; border-left-width: 1px; border-left-color: rgb(204, 204, 204); border-left-style: solid; padding-left: 1ex;">
<div style="word-wrap: break-word;" class="">
<div id="m_2492479024697317942bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; margin: 0px;" class="">Additionally, not discarding previous comments, one way
the language could be improved is by replacing (or rather
augmenting) optional binding with a faster syntax.</div>
<div id="m_2492479024697317942bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; margin: 0px;" class=""><br class=""></div>
<div id="m_2492479024697317942bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; margin: 0px;" class="">ex.</div>
<div id="m_2492479024697317942bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; margin: 0px;" class=""><br class=""></div>
<div id="m_2492479024697317942bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; margin: 0px;" class="">func test( name : String?, name2 :String? ){</div>
<div id="m_2492479024697317942bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; margin: 0px;" class=""> name! , name2! {</div>
<div id="m_2492479024697317942bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; margin: 0px;" class="">// inside this block, “name” and “name2” are
non-optional</div>
<div id="m_2492479024697317942bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; margin: 0px;" class=""> <span class="Apple-converted-space"> </span>} else {</div>
<div id="m_2492479024697317942bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; margin: 0px;" class=""> <span class="Apple-converted-space"> </span>// no forced unwrapping, just
optional else case</div>
<div id="m_2492479024697317942bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; margin: 0px;" class=""> }</div>
<div id="m_2492479024697317942bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; margin: 0px;" class="">}</div>
<div id="m_2492479024697317942bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; margin: 0px;" class=""><br class=""></div>
<div id="m_2492479024697317942bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; margin: 0px;" class="">Whereas the alternative (current optional binding),
requires a re-definition of variables and an additional “if”
operator. Besides the extra characters involved in typing and
reading it, usually variables have specific names that the user
does not want to augument.</div>
<div id="m_2492479024697317942bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; margin: 0px;" class=""><br class=""></div>
<div id="m_2492479024697317942bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; margin: 0px;" class="">
<div id="m_2492479024697317942bloop_customfont" style="margin: 0px;" class="">func test( name : String?, name2 :String?
){</div>
<div id="m_2492479024697317942bloop_customfont" style="margin: 0px;" class=""> <span class="Apple-converted-space"> </span>if let nameUnwrapped = name ,
let name2Unwrapped = name2 {</div>
<div id="m_2492479024697317942bloop_customfont" style="margin: 0px;" class=""><br class=""></div>
<div id="m_2492479024697317942bloop_customfont" style="margin: 0px;" class=""> <span class="Apple-converted-space"> </span>} else {</div>
<div id="m_2492479024697317942bloop_customfont" style="margin: 0px;" class=""> }</div>
<div id="m_2492479024697317942bloop_customfont" style="margin: 0px;" class="">}</div>
<div id="m_2492479024697317942bloop_customfont" style="margin: 0px;" class=""><br class=""></div>
<div id="m_2492479024697317942bloop_customfont" style="margin: 0px;" class="">
<div id="m_2492479024697317942bloop_customfont" style="margin: 0px;" class="">func test( name : String?, name2 :String?
){</div>
<div id="m_2492479024697317942bloop_customfont" style="margin: 0px;" class=""> <span class="Apple-converted-space"> </span>guard let nameUnwrapped = name
, let name2Unwrapped = name2 else {</div>
<div id="m_2492479024697317942bloop_customfont" style="margin: 0px;" class=""><br class=""></div>
<div id="m_2492479024697317942bloop_customfont" style="margin: 0px;" class=""> <span class="Apple-converted-space"> </span>}</div>
<div id="m_2492479024697317942bloop_customfont" style="margin: 0px;" class=""><br class=""></div>
<div id="m_2492479024697317942bloop_customfont" style="margin: 0px;" class="">}</div>
</div>
<div id="m_2492479024697317942bloop_customfont" style="margin: 0px;" class=""><br class=""></div>
<div id="m_2492479024697317942bloop_customfont" style="margin: 0px;" class="">The fact that we don’t need a
“nameUnwrapped” variable (which is unsightly and requires
refractoring) is one thing that still makes forced unwrapping still
very much a necessary or common part of Swift coding, even where it
could be replaced with optional binding.</div>
</div>
<div id="m_2492479024697317942bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; margin: 0px;" class=""><br class=""></div>
<div id="m_2492479024697317942bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; margin: 0px;" class=""><br class=""></div>
<br class="">
<div id="m_2492479024697317942bloop_sign_1488852857050308864" class="m_2492479024697317942bloop_sign"></div>
<br class="">
<p class="m_2492479024697317942airmail_on">On March 6, 2017 at
7:20:40 PM, Elijah Johnson (<a href="mailto:ejrx7753@gmail.com" target="_blank" class="">ejrx7753@gmail.com</a>) wrote:</p>
<blockquote type="cite" class="m_2492479024697317942clean_bq">
<div style="word-wrap: break-word;" class="">
<div class="">
<div id="m_2492479024697317942bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; margin: 0px;" class=""><span class="">Hi,</span></div>
<div id="m_2492479024697317942bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; margin: 0px;" class=""><span class=""><br class=""></span></div>
<div id="m_2492479024697317942bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; margin: 0px;" class=""><span class="">I’ve been recently considering Swift on the
server-side, and there came up the question, “what happens when a
null optional is forcibly unwrapped?” and the answer was clearly
that not only would the request crash, but the entire server would
also crash, since the server itself is/would be also written in
Swift.</span></div>
<div id="m_2492479024697317942bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; margin: 0px;" class=""><span class=""><br class=""></span></div>
<div id="m_2492479024697317942bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; margin: 0px;" class=""><span class="">I think that this highlights serveral
weaknesses in Swift’s “null safety” attempts. The first is that
there needs to be a way to isolate blocks of code so that a “null
pointer exception” does not crash the system. I think it is fair to
say, in the language of Java, that these are really “runtime
exceptions” and for some reason are being treated as segmentation
faults would be in C/C++. In my opinion, the existence of these
things has the ability to bring Swift down below Java and closer to
an unamanged language. Not really sure why it would ever be
desireable, but in terms of server-side programming, it is
definitely a serious issue.</span></div>
<div id="m_2492479024697317942bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; margin: 0px;" class=""><span class=""><br class=""></span></div>
<div id="m_2492479024697317942bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; margin: 0px;" class=""><span class="">Secondly, Swift’s “null safety” is really
completely undermined by these “force-unwrap” errors. I agree with
the usage of new language features like guard, optional binding,
etc to remove a null value, but I see this force-unwrap as
extremely pervasive for a lot of reasons:</span></div>
<div id="m_2492479024697317942bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; margin: 0px;" class=""><span class=""><br class=""></span></div>
<div id="m_2492479024697317942bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; margin: 0px;" class=""><span class="">1. When porting code from a C style
language to Swift, force-unwrap is needed to make the code work
without refractoring.</span></div>
<div id="m_2492479024697317942bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; margin: 0px;" class=""><span class="">2. XCode itself reccomends this operator
and when it is used to satisfy a requirement, then it can be left
in the code</span></div>
<div id="m_2492479024697317942bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; margin: 0px;" class=""><span class="">3. Some styles of coding just can’t work
without force-unwrap.</span></div>
<div id="m_2492479024697317942bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; margin: 0px;" class=""><span class=""><br class=""></span></div>
<div id="m_2492479024697317942bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; margin: 0px;" class=""><span class="">I don’t think the logic of making the
consequences extreme for making a mistake are a rational for making
better coders. In fact, I personally see the “force-unwrap”
operator having very great potential usage as a deliberate
assertion exception - the programmer demands that a certain value
be non-null for execution to continue, only there should be a
proper scope and context where these exceptions can propogate to.
On debug modes, one might want it to pause on the line, but for
other uses, it should be caught IMO - on regular code by the user,
and inside dispatch blocks by the queue itself. For a multithreaded
app or server to exit, the user should have to explicitly write
exit(0), isn’t this the goal of a managed language? Maybe in some
cases, Apple will want the program to crash, but if Swift is given
an audience not just with Apple hardware, then it should have more
flexibility IMO.</span></div>
<div id="m_2492479024697317942bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; margin: 0px;" class=""><span class=""><br class=""></span></div>
<div id="m_2492479024697317942bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; margin: 0px;" class=""><span class="">Elijah</span></div>
<div id="m_2492479024697317942bloop_sign_1488843525920942080" class="m_2492479024697317942bloop_sign"></div>
</div>
</div>
</blockquote>
</div>
<br class="">
______________________________<wbr class="">_________________<br class="">
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</div>
</div>
</div>
</div>
</blockquote>
</div>
</blockquote>
</div>
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