Require Swift 5.3 or higher to build (#3553)

* Require Swift 5.3 or higher to build

* Remove Swift Version Support tables from readmes

These weren't exactly accurate because SwiftLint should still work with
older Swift versions long after we update the minimum version of Swift
needed to _build_ the tool. So I doubt this table was very helpful to
anyone.

CHANGELOG.md

@@ -2,7 +2,8 @@
 
 #### Breaking
 
-* None.
+* SwiftLint now requires Swift 5.3 or higher to build.  
+  [JP Simard](https://github.com/jpsim)
 
 #### Experimental
 

README.md

@@ -60,19 +60,7 @@ running it.
 ### Installing from source:
 
 You can also build and install from source by cloning this project and running
-`make install` (Xcode 11.4 or later).
+`make install` (Xcode 12 or later).
-
-### Known Installation Issues On MacOS Before 10.14.4
-
-Starting with [SwiftLint 0.32.0](https://github.com/realm/SwiftLint/releases/tag/0.32.0), if you get
-an error similar to `dyld: Symbol not found: _$s11SubSequenceSlTl` when running SwiftLint,
-you'll need to install the [Swift 5 Runtime Support for Command Line Tools](https://support.apple.com/kb/DL1998).
-
-Alternatively, you can:
-
-* Update to macOS 10.14.4 or later
-* Install Xcode 11.4 or later at `/Applications/Xcode.app`
-* Rebuild SwiftLint from source using Xcode 11.4 or later
 
 ## Usage
 
@@ -230,19 +218,6 @@ On Linux, SourceKit is expected to be located in
 `/usr/lib/libsourcekitdInProc.so` or specified by the `LINUX_SOURCEKIT_LIB_PATH`
 environment variable.
 
-### Swift Version Support
-
-Here's a reference of which SwiftLint version to use for a given Swift version.
-
-| Swift version   | Last supported SwiftLint release |
-|:----------------|:---------------------------------|
-| Swift 1.x       | SwiftLint 0.1.2                  |
-| Swift 2.x       | SwiftLint 0.18.1                 |
-| Swift 3.x       | SwiftLint 0.25.1                 |
-| Swift 4.0-4.1.x | SwiftLint 0.28.2                 |
-| Swift 4.2.x     | SwiftLint 0.35.0                 |
-| Swift 5.x       | Latest                           |
-
 ## Rules
 
 Over 100 rules are included in SwiftLint and the Swift community (that's you!)

README_CN.md

@@ -161,19 +161,6 @@ $ TOOLCHAINS=com.apple.dt.toolchain.Swift_2_3 swiftlint autocorrect
 
 在 Linux 上，SourceKit 默认需要位于 `/usr/lib/libsourcekitdInProc.so` 或者通过 `LINUX_SOURCEKIT_LIB_PATH` 环境变量进行指定。
 
-### Swift Version Support
-
-这里有一份 SwiftLint 版本和对应该 Swift 版本的对照表作为参考。
-
-| Swift 版本      | 最后一个 SwiftLint 支持版本 |
-|:----------------|:----------------------------|
-| Swift 1.x       | SwiftLint 0.1.2             |
-| Swift 2.x       | SwiftLint 0.18.1            |
-| Swift 3.x       | SwiftLint 0.25.1            |
-| Swift 4.0-4.1.x | SwiftLint 0.28.2            |
-| Swift 4.2.x     | SwiftLint 0.35.0            |
-| Swift 5.x       | 最新的                      |
-
 ## 规则
 
 SwiftLint 已经包含了超过 75 条规则，并且我们希望 Swift 社区（就是你！）会在以后有更多的贡献，我们鼓励提交 [Pull Requests](CONTRIBUTING.md)。

Tests/SwiftLintFrameworkTests/CompilerProtocolInitRuleTests.swift

@@ -23,19 +23,3 @@ class CompilerProtocolInitRuleTests: XCTestCase {
         )
     }
 }
-
-// https://bugs.swift.org/browse/SR-11501
-#if SWIFT_PACKAGE && os(macOS) && compiler(<5.2)
-private enum UnwrapError: Error {
-    case missingValue
-}
-
-private func XCTUnwrap<T>(_ expression: @autoclosure () throws -> T?,
-                          _ message: @autoclosure () -> String = "") throws -> T {
-    if let value = try expression() {
-        return value
-    } else {
-        throw UnwrapError.missingValue
-    }
-}
-#endif

azure-pipelines.yml

@@ -8,8 +8,6 @@ jobs:
   strategy:
     maxParallel: 10
     matrix:
-      swift52:
-        containerImage: swift:5.2
       swift53:
         containerImage: swift:5.3
   container: $[ variables['containerImage'] ]
@@ -23,14 +21,10 @@ jobs:
   strategy:
     maxParallel: 10
     matrix:
-      xcode114:
-        DEVELOPER_DIR: /Applications/Xcode_11.4.app
-      xcode115:
-        DEVELOPER_DIR: /Applications/Xcode_11.5.app
-      xcode116:
-        DEVELOPER_DIR: /Applications/Xcode_11.6.app
       xcode12:
         DEVELOPER_DIR: /Applications/Xcode_12.app
+      xcode124:
+        DEVELOPER_DIR: /Applications/Xcode_12.4.app
   steps:
     - script: |
         sw_vers
@@ -55,14 +49,10 @@ jobs:
   strategy:
     maxParallel: 10
     matrix:
-      xcode114:
-        DEVELOPER_DIR: /Applications/Xcode_11.4.app
-      xcode115:
-        DEVELOPER_DIR: /Applications/Xcode_11.5.app
-      xcode116:
-        DEVELOPER_DIR: /Applications/Xcode_11.6.app
       xcode12:
         DEVELOPER_DIR: /Applications/Xcode_12.app
+      xcode124:
+        DEVELOPER_DIR: /Applications/Xcode_12.4.app
   steps:
     - script: |
         sw_vers
@@ -77,7 +67,7 @@ jobs:
   pool:
     vmImage: 'macOS-10.15'
   variables:
-    DEVELOPER_DIR: /Applications/Xcode_12.app
+    DEVELOPER_DIR: /Applications/Xcode_12.4.app
   steps:
     - script: bundle install --path vendor/bundle
       displayName: bundle install
@@ -90,7 +80,7 @@ jobs:
   pool:
     vmImage: 'macOS-10.15'
   variables:
-    DEVELOPER_DIR: /Applications/Xcode_12.app
+    DEVELOPER_DIR: /Applications/Xcode_12.4.app
   steps:
     - script: make analyze
       displayName: Run SwiftLint Analyze
@@ -99,7 +89,7 @@ jobs:
   pool:
     vmImage: 'macOS-10.15'
   variables:
-    DEVELOPER_DIR: /Applications/Xcode_12.app
+    DEVELOPER_DIR: /Applications/Xcode_12.4.app
   steps:
     - script: swift run --sanitize=thread swiftlint lint --lenient
       displayName: Pre-cache SwiftLint Run
@@ -112,7 +102,7 @@ jobs:
   pool:
     vmImage: 'macOS-10.15'
   variables:
-    DEVELOPER_DIR: /Applications/Xcode_12.app
+    DEVELOPER_DIR: /Applications/Xcode_12.4.app
   steps:
     - script: swift run swiftlint generate-docs
       displayName: Run swiftlint generate-docs