Fix loss of changes when multiple target the same start point

While one might at first think that multiple changes should conflict if they
target that same start point, that is not necessarily true as long as no more
than one of them includes deletions: There may be an arbitrary number of
insertions at the same position (regular remapping never just inserts but
patterns can).

5 files changed, 55 insertions, 3 deletions

diff --git a/src/main/kotlin/com/replaymod/gradle/remap/PsiMapper.kt b/src/main/kotlin/com/replaymod/gradle/remap/PsiMapper.kt
index a8d9f2a..c620c4c 100644
--- a/src/main/kotlin/com/replaymod/gradle/remap/PsiMapper.kt
+++ b/src/main/kotlin/com/replaymod/gradle/remap/PsiMapper.kt
@@ -31,7 +31,7 @@ internal class PsiMapper(
 ) {
     private val mixinMappings = mutableMapOf<String, ClassMapping<*, *>>()
     private val errors = mutableListOf<Pair<Int, String>>()
-    private val changes = TreeMap<TextRange, String>(Comparator.comparing<TextRange, Int> { it.startOffset })
+    private val changes = TreeMap<TextRange, String>(compareBy<TextRange> { it.startOffset }.thenBy { it.endOffset })
 
     private fun error(at: PsiElement, message: String) {
         val line = StringUtil.offsetToLineNumber(file.text, at.textOffset)
@@ -40,7 +40,13 @@ internal class PsiMapper(
 
     private fun replace(e: PsiElement, with: String) = replace(e.textRange, with)
     private fun replace(textRange: TextRange, with: String) {
-        changes[textRange] = with
+        changes.compute(textRange) { _, replacement ->
+            if (replacement != null) {
+                replacement + with
+            } else {
+                with
+            }
+        }
     }
 
     private fun replaceIdentifier(parent: PsiElement, with: String) {
diff --git a/src/test/java/a/pkg/A.java b/src/test/java/a/pkg/A.java
index b5480d4..32fa2a9 100644
--- a/src/test/java/a/pkg/A.java
+++ b/src/test/java/a/pkg/A.java
@@ -10,6 +10,8 @@ public class A extends AParent implements AInterface {
     public A(A arg) {
     }
 
+    public static A create() { return new A(); }
+
     public void aMethod() {
         aInterfaceMethod();
     }
diff --git a/src/test/java/b/pkg/B.java b/src/test/java/b/pkg/B.java
index 88f46cf..3af7381 100644
--- a/src/test/java/b/pkg/B.java
+++ b/src/test/java/b/pkg/B.java
@@ -10,6 +10,8 @@ public class B extends BParent implements BInterface {
     public B(B arg) {
     }
 
+    public static B create() { return new B(); }
+
     public void bMethod() {
         bInterfaceMethod();
     }
diff --git a/src/test/kotlin/com/replaymod/gradle/remap/pattern/TestChangeMerging.kt b/src/test/kotlin/com/replaymod/gradle/remap/pattern/TestChangeMerging.kt
new file mode 100644
index 0000000..e8b86d2
--- /dev/null
+++ b/src/test/kotlin/com/replaymod/gradle/remap/pattern/TestChangeMerging.kt
@@ -0,0 +1,36 @@
+package com.replaymod.gradle.remap.pattern
+
+import com.replaymod.gradle.remap.util.TestData
+import io.kotest.matchers.collections.shouldHaveSize
+import io.kotest.matchers.shouldBe
+import io.kotest.matchers.string.shouldContain
+import org.junit.jupiter.api.Test
+
+class TestChangeMerging {
+    @Test
+    fun `should work when mixed with remapping`() {
+        TestData.remap("""
+            class Test {
+                private void test() {
+                    a.pkg.A.create().aMethod();
+                }
+            }
+        """.trimIndent(), """
+            @remap.Pattern
+            private void addWrapping(a.pkg.A a) {
+                a.aMethod();
+            }
+        """.trimIndent(), """
+            @remap.Pattern
+            private void addWrapping(a.pkg.A a) {
+                (((a.bMethod())));
+            }
+        """.trimIndent()) shouldBe """
+            class Test {
+                private void test() {
+                    (((b.pkg.B.create().bMethod())));
+                }
+            }
+        """.trimIndent()
+    }
+}
\ No newline at end of file
diff --git a/src/test/kotlin/com/replaymod/gradle/remap/util/TestData.kt b/src/test/kotlin/com/replaymod/gradle/remap/util/TestData.kt
index 0f83373..adb6f52 100644
--- a/src/test/kotlin/com/replaymod/gradle/remap/util/TestData.kt
+++ b/src/test/kotlin/com/replaymod/gradle/remap/util/TestData.kt
@@ -41,9 +41,15 @@ object TestData {
             findClasspathEntry("org.spongepowered.asm.mixin.Mixin"),
             findClasspathEntry("a.pkg.A"),
         )
+        patternAnnotation = "remap.Pattern"
     }
 
-    fun remap(content: String): String = transformer.remap(mapOf("test.java" to content))["test.java"]!!.first
+    fun remap(content: String, patternsBefore: String = "", patternsAfter: String = ""): String = transformer.remap(mapOf(
+        "test.java" to content,
+        "pattern.java" to "class Patterns {\n$patternsBefore\n}",
+    ), mapOf(
+        "pattern.java" to "class Patterns {\n$patternsAfter\n}",
+    ))["test.java"]!!.first
     fun remapWithErrors(content: String) = transformer.remap(mapOf("test.java" to content))["test.java"]!!
 
     fun remapKt(content: String): String = transformer.remap(mapOf("test.kt" to content))["test.kt"]!!.first