Enable unused import detection by default

.periphery.linux.yml

@@ -6,4 +6,3 @@ targets:
 - PeripheryTests
 - SPMTests
 - AccessibilityTests
-enable_unused_import_analysis: true

.periphery.yml

@@ -8,4 +8,3 @@ targets:
 - XcodeTests
 - SPMTests
 - AccessibilityTests
-enable_unused_import_analysis: true

CHANGELOG.md

@@ -6,7 +6,7 @@
 
 ##### Enhancements
 
-- None.
+- Unused import detection is now enabled by default.
 
 ##### Bug Fixes
 

README.md

@@ -30,6 +30,7 @@
     - [Enumerations](#enumerations)
     - [Assign-only Properties](#assign-only-properties)
     - [Redundant Public Accessibility](#redundant-public-accessibility)
+    - [Unused Imports](#unused-imports)
     - [Objective-C](#objective-c)
     - [Encodable](#encodable)
     - [XCTestCase](#xctestcase)
@@ -301,6 +302,12 @@ Declarations that are marked `public` yet are not referenced from outside their
 
 This analysis can be disabled with `--disable-redundant-public-analysis`.
 
+### Unused Imports
+
+Periphery can detect unused imports of targets it has scanned, i.e. those specified with the `--targets` argument. It cannot detect unused imports of other targets because the Swift source files are unavailable and uses of `@_exported` cannot be observed. `@_exported` is problematic because it changes the public interface of a target such that the declarations exported by the target are no longer necessarily declared by the imported target. For example, the `Foundation` target exports `Dispatch`, among other targets. If any given source file imports `Foundation` and references `DispatchQueue` but no other declarations from `Foundation`, then the `Foundation` import cannot be removed as it would also make the `DispatchQueue` type unavailable. To avoid false positives, therefore, Periphery only detects unused imports of targets it has scanned.
+
+Periphery will likely produce false positives for targets with mixed Swift and Objective-C, as Periphery cannot scan the Objective-C files. It is recommended therefore to disable unused import detection for projects with a significant amount of Objective-C, or manually exclude the mixed language targets from the results.
+
 ### Objective-C
 
 Periphery cannot analyze Objective-C code since types may be dynamically typed.

Sources/Frontend/Commands/ScanCommand.swift

@@ -57,7 +57,7 @@ struct ScanCommand: FrontendCommand {
     @Flag(help: "Disable identification of redundant public accessibility")
     var disableRedundantPublicAnalysis: Bool = defaultConfiguration.$disableRedundantPublicAnalysis.defaultValue
 
-    @Flag(help: "Enable identification of unused imports (experimental)")
+    @Flag(help: "Enable identification of unused imports")
     var enableUnusedImportAnalysis: Bool = defaultConfiguration.$enableUnusedImportsAnalysis.defaultValue
 
     @Flag(help: "Retain properties that are assigned, but never used")

Sources/Shared/Configuration.swift

@@ -77,7 +77,7 @@ public final class Configuration {
     @Setting(key: "disable_redundant_public_analysis", defaultValue: false)
     public var disableRedundantPublicAnalysis: Bool
 
-    @Setting(key: "enable_unused_import_analysis", defaultValue: false)
+    @Setting(key: "enable_unused_import_analysis", defaultValue: true)
     public var enableUnusedImportsAnalysis: Bool
 
     @Setting(key: "retain_codable_properties", defaultValue: false)
@@ -163,7 +163,7 @@ public final class Configuration {
         if $retainObjcAnnotated.hasNonDefaultValue {
             config[$retainObjcAnnotated.key] = retainObjcAnnotated
         }
-        
+
         if $retainPublic.hasNonDefaultValue {
             config[$retainPublic.key] = retainPublic
         }