From d2148c730e8523df85d43168d7c17feb694151bf Mon Sep 17 00:00:00 2001
From: Nick Lockwood <nick@charcoaldesign.co.uk>
Date: Tue, 23 Jan 2024 22:45:48 +0000
Subject: [PATCH] Preserve internal import

---
 Sources/Rules.swift               | 10 ++++++----
 Tests/RulesTests+Redundancy.swift |  5 +++++
 2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/Sources/Rules.swift b/Sources/Rules.swift
index e23a272a..493ea903 100644
--- a/Sources/Rules.swift
+++ b/Sources/Rules.swift
@@ -7310,17 +7310,19 @@ public struct _FormatRules {
         help: "Remove redundant internal access control."
     ) { formatter in
         formatter.forEach(.keyword("internal")) { internalKeywordIndex, _ in
-            let accessControlLevels = ["public", "package", "internal", "private", "fileprivate"]
+            // Don't remove import acl
+            if formatter.next(.nonSpaceOrComment, after: internalKeywordIndex) == .keyword("import") {
+                return
+            }
 
-            // If we're inside an extension, than `internal` is only redundant
-            // if the extension itself is `internal`.
+            // If we're inside an extension, then `internal` is only redundant if the extension itself is `internal`.
             if let startOfScope = formatter.startOfScope(at: internalKeywordIndex),
                let typeKeywordIndex = formatter.indexOfLastSignificantKeyword(at: startOfScope),
                formatter.tokens[typeKeywordIndex] == .keyword("extension"),
                // In the language grammar, the ACL level always directly precedes the
                // `extension` keyword if present.
                let previousToken = formatter.last(.nonSpaceOrCommentOrLinebreak, before: typeKeywordIndex),
-               accessControlLevels.contains(previousToken.string),
+               ["public", "package", "internal", "private", "fileprivate"].contains(previousToken.string),
                previousToken.string != "internal"
             {
                 // The extension has an explicit ACL other than `internal`, so is not internal.
diff --git a/Tests/RulesTests+Redundancy.swift b/Tests/RulesTests+Redundancy.swift
index a89eef33..76f8ff3a 100644
--- a/Tests/RulesTests+Redundancy.swift
+++ b/Tests/RulesTests+Redundancy.swift
@@ -9165,6 +9165,11 @@ class RedundancyTests: RulesTests {
         testFormatting(for: input, output, rule: FormatRules.redundantInternal, exclude: ["redundantExtensionACL"])
     }
 
+    func testPreserveInternalImport() {
+        let input = "internal import MyPackage"
+        testFormatting(for: input, rule: FormatRules.redundantInternal)
+    }
+
     // MARK: - noExplicitOwnership
 
     func testRemovesOwnershipKeywordsFromFunc() {