Reduce spurious change tracking

Sources/Formatter.swift

@@ -235,10 +235,10 @@ public extension Formatter {
 
     /// Replaces the token at the specified index with a new token
     func replaceToken(at index: Int, with token: Token) {
-        if token != tokens[index] {
+        if trackChanges, token.string != tokens[index].string {
             trackChange(at: index)
-            tokens[index] = token
         }
+        tokens[index] = token
     }
 
     /// Replaces the tokens in the specified range with new tokens

Sources/Rules.swift

@@ -752,7 +752,8 @@ public struct _FormatRules {
 
     /// Remove blank lines immediately after an opening brace, bracket, paren or chevron
     public let blankLinesAtStartOfScope = FormatRule(
-        help: "Remove leading blank line at the start of a scope."
+        help: "Remove leading blank line at the start of a scope.",
+        orderAfter: ["organizeDeclarations"]
     ) { formatter in
         formatter.forEach(.startOfScope) { i, token in
             guard ["{", "(", "[", "<"].contains(token.string),
@@ -784,7 +785,8 @@ public struct _FormatRules {
     /// Remove blank lines immediately before a closing brace, bracket, paren or chevron
     /// unless it's followed by more code on the same line (e.g. } else { )
     public let blankLinesAtEndOfScope = FormatRule(
-        help: "Remove trailing blank line at the end of a scope."
+        help: "Remove trailing blank line at the end of a scope.",
+        orderAfter: ["organizeDeclarations"]
     ) { formatter in
         formatter.forEach(.endOfScope) { i, token in
             guard ["}", ")", "]", ">"].contains(token.string),

Tests/FormatterTests.swift

@@ -441,4 +441,15 @@ class FormatterTests: XCTestCase {
         """))
         XCTAssertEqual(formatter.endOfScope(at: 4), 13)
     }
+
+    // MARK: change tracking
+
+    func testTrackChangesIgnoresLinebreakIndex() {
+        let formatter = Formatter(tokenize("\n\n"), trackChanges: true)
+        var tokens = formatter.tokens
+        tokens.insert(tokens.removeLast(), at: 0)
+        XCTAssertNotEqual(formatter.tokens, tokens)
+        formatter.replaceTokens(in: 0 ..< 2, with: tokens)
+        XCTAssert(formatter.changes.isEmpty)
+    }
 }

Tests/XCTestManifests.swift

@@ -154,6 +154,7 @@ extension FormatterTests {
         ("testRemoveNextTokenWhileEnumerating", testRemoveNextTokenWhileEnumerating),
         ("testRemovePreviousTokenWhileEnumerating", testRemovePreviousTokenWhileEnumerating),
         ("testSwiftVersionNext", testSwiftVersionNext),
+        ("testTrackChangesIgnoresLinebreakIndex", testTrackChangesIgnoresLinebreakIndex),
     ]
 }