<html><head><style>
body {
font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
padding:1em;
margin:auto;
background:#fefefe;
}
h1, h2, h3, h4, h5, h6 {
font-weight: bold;
}
h1 {
color: #000000;
font-size: 28pt;
}
h2 {
border-bottom: 1px solid #CCCCCC;
color: #000000;
font-size: 24px;
}
h3 {
font-size: 18px;
}
h4 {
font-size: 16px;
}
h5 {
font-size: 14px;
}
h6 {
color: #777777;
background-color: inherit;
font-size: 14px;
}
hr {
height: 0.2em;
border: 0;
color: #CCCCCC;
background-color: #CCCCCC;
display: inherit;
}
p, blockquote, ul, ol, dl, li, table, pre {
margin: 15px 0;
}
a, a:visited {
color: #4183C4;
background-color: inherit;
text-decoration: none;
}
#message {
border-radius: 6px;
border: 1px solid #ccc;
display:block;
width:100%;
height:60px;
margin:6px 0px;
}
button, #ws {
font-size: 12 pt;
padding: 4px 6px;
border-radius: 5px;
border: 1px solid #bbb;
background-color: #eee;
}
code, pre, #ws, #message {
font-family: Monaco;
font-size: 10pt;
border-radius: 3px;
background-color: #F8F8F8;
color: inherit;
}
code {
border: 1px solid #EAEAEA;
margin: 0 2px;
padding: 0 5px;
}
pre {
border: 1px solid #CCCCCC;
overflow: auto;
padding: 4px 8px;
}
pre > code {
border: 0;
margin: 0;
padding: 0;
}
#ws { background-color: #f8f8f8; }
.bloop_markdown table {
border-collapse: collapse;
font-family: Helvetica, arial, freesans, clean, sans-serif;
color: rgb(51, 51, 51);
font-size: 15px; line-height: 25px;
padding: 0; }
.bloop_markdown table tr {
border-top: 1px solid #cccccc;
background-color: white;
margin: 0;
padding: 0; }
.bloop_markdown table tr:nth-child(2n) {
background-color: #f8f8f8; }
.bloop_markdown table tr th {
font-weight: bold;
border: 1px solid #cccccc;
margin: 0;
padding: 6px 13px; }
.bloop_markdown table tr td {
border: 1px solid #cccccc;
margin: 0;
padding: 6px 13px; }
.bloop_markdown table tr th :first-child, table tr td :first-child {
margin-top: 0; }
.bloop_markdown table tr th :last-child, table tr td :last-child {
margin-bottom: 0; }
.bloop_markdown blockquote{
border-left: 4px solid #dddddd;
padding: 0 15px;
color: #777777; }
blockquote > :first-child {
margin-top: 0; }
blockquote > :last-child {
margin-bottom: 0; }
code, pre, #ws, #message {
word-break: normal;
word-wrap: normal;
}
hr {
display: inherit;
}
.bloop_markdown :first-child {
-webkit-margin-before: 0;
}
code, pre, #ws, #message {
font-family: Menlo, Consolas, Liberation Mono, Courier, monospace;
}
.send { color:#77bb77; }
.server { color:#7799bb; }
.error { color:#AA0000; }</style></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"><div class="bloop_markdown"><p>Hello dear Swift community,</p>
<p>I was updating some of my libraries where I noticed that the new <code>open</code> access modifier made the <code>public</code> modifier inconsistent in one way.</p>
<p>Conformances to protocols is logically the same as inheritances on classes. </p>
<ul>
<li><code>Conformances == (abstract) inheritance</code></li>
</ul>
<p>That said we should allow protocols to be <code>open/public</code> like we now allow this distinction for classes.</p>
<ul>
<li><code>open protocol</code> from module A should mean that I’m allowed to conform to it in module B</li>
<li><code>public protocol</code> will act as an interface in module B</li>
</ul>
<p>Not only sounds this behavior like ‘nice to have’, it’s inconsistency and it’s a ‘really need’ + a source breaking change in general.</p>
<p>A common mistake in Swift 3.0 would be to hide protocol members behind <code>public</code> modifier for protocols that meant to be <code>open</code>. If a protocol member in an open class is disallowed to be overridden by the <code>public</code> modifier and this behavior is fixed, that will imply that you’ll have to open the member which you intended to be not overridable. </p>
<pre><code class="swift">// Before:
// In module A
public protocol Proto {
func doSomething()
}
open class Base : Proto {
// Dissallow to override - this would be a common mistake
public func doSomething() {}
}
// Used in module B - so it should be `open` after all
class Test : Proto {
func doSomething() {}
}
// After:
// In module A
open protocol Proto {
func doSomething()
}
open class Base : Proto {
// Whops we have to grant the ability to override this method now
// I made a mistake designing my protocol in Swift 3.0 :/
open func doSomething() {}
}
// In module B
class Test2 : Base {
// Uuuuuuh I can do bad things with this now if the module A was not redesigned to fix this. :)))
override func doSomething() {}
}
</code></pre>
<p>Personally I don’t have any feeling of how huge the impact might be on Swift if this behavior will be fixed. I also cannot tell if it’s something for Swift 3.x or Swift 4.0.</p>
<p></p></div><div class="bloop_original_html"><style>body{font-family:Helvetica,Arial;font-size:13px}</style><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><br><div id="bloop_sign_1471887332279883776" class="bloop_sign"><div style="font-family:helvetica,arial;font-size:13px">-- <br>Adrian Zubarev<br>Sent with Airmail</div></div></div><div class="bloop_markdown"><p></p></div></body></html>