Debugger: Support Kotlin variables for inlined lambdas inside inline functions (KT-31418)

compiler/backend/src/org/jetbrains/kotlin/codegen/inline/MethodInliner.kt

@@ -487,7 +487,12 @@ class MethodInliner(
                 name: String, desc: String, signature: String?, start: Label, end: Label, index: Int
             ) {
                 if (isInliningLambda || GENERATE_DEBUG_INFO) {
-                    val varSuffix = if (inliningContext.isRoot && !isFakeLocalVariableForInline(name)) INLINE_FUN_VAR_SUFFIX else ""
+                    val isInlineFunctionMarker = name.startsWith(JvmAbi.LOCAL_VARIABLE_NAME_PREFIX_INLINE_FUNCTION)
+                    val varSuffix = when {
+                        inliningContext.isRoot && !isInlineFunctionMarker -> INLINE_FUN_VAR_SUFFIX
+                        else -> ""
+                    }
+
                     val varName = if (!varSuffix.isEmpty() && name == AsmUtil.THIS) AsmUtil.INLINE_DECLARATION_SITE_THIS else name
                     super.visitLocalVariable(varName + varSuffix, desc, signature, start, end, getNewIndex(index))
                 }

idea/jvm-debugger/jvm-debugger-core/src/org/jetbrains/kotlin/idea/debugger/debuggerUtil.kt

@@ -58,7 +58,7 @@ fun isInsideInlineArgument(
                 val lambdaClassName = asmTypeForAnonymousClass(bindingContext, inlineArgument)
                     .internalName.substringAfterLast("/")
 
-                variableName == "-$functionName-$lambdaClassName"
+                dropInlineSuffix(variableName) == "-$functionName-$lambdaClassName"
             } else {
                 // For Kotlin up to 1.3.10
                 lambdaOrdinalByLocalVariable(variableName) == lambdaOrdinal
@@ -100,6 +100,7 @@ private fun Location.visibleVariables(debugProcess: DebugProcessImpl): List<Loca
     return stackFrame.visibleVariables()
 }
 
+// For Kotlin up to 1.3.10
 private fun lambdaOrdinalByLocalVariable(name: String): Int {
     try {
         val nameWithoutPrefix = name.removePrefix(JvmAbi.LOCAL_VARIABLE_NAME_PREFIX_INLINE_ARGUMENT)
@@ -110,6 +111,7 @@ private fun lambdaOrdinalByLocalVariable(name: String): Int {
     }
 }
 
+// For Kotlin up to 1.3.10
 private fun functionNameByLocalVariable(name: String): String {
     val nameWithoutPrefix = name.removePrefix(JvmAbi.LOCAL_VARIABLE_NAME_PREFIX_INLINE_ARGUMENT)
     return nameWithoutPrefix.substringAfterLast("$", "unknown")

idea/jvm-debugger/jvm-debugger-core/src/org/jetbrains/kotlin/idea/debugger/stackFrame/KotlinStackFrame.kt

@@ -129,7 +129,7 @@ class KotlinStackFrame(frame: StackFrameProxyImpl) : JavaStackFrame(StackFrameDe
         val inlineDepth = getInlineDepth(variables)
         val declarationSiteThis = variables.firstOrNull { v ->
             val name = v.name()
-            name.endsWith(INLINE_FUN_VAR_SUFFIX) && name.dropInlineSuffix() == AsmUtil.INLINE_DECLARATION_SITE_THIS
+            name.endsWith(INLINE_FUN_VAR_SUFFIX) && dropInlineSuffix(name) == AsmUtil.INLINE_DECLARATION_SITE_THIS
         }
 
         if (inlineDepth > 0 && declarationSiteThis != null) {
@@ -282,7 +282,7 @@ class KotlinStackFrame(frame: StackFrameProxyImpl) : JavaStackFrame(StackFrameDe
     }
 
     private fun LocalVariableProxyImpl.remapThisVariableIfNeeded(customName: String? = null): LocalVariableProxyImpl {
-        val name = this.name().dropInlineSuffix()
+        val name = dropInlineSuffix(this.name())
 
         @Suppress("ConvertToStringTemplate")
         return when {
@@ -326,15 +326,6 @@ class KotlinStackFrame(frame: StackFrameProxyImpl) : JavaStackFrame(StackFrameDe
         return label
     }
 
-    private fun String.dropInlineSuffix(): String {
-        val depth = getInlineDepth(this)
-        if (depth == 0) {
-            return this
-        }
-
-        return dropLast(depth * INLINE_FUN_VAR_SUFFIX.length)
-    }
-
     private fun LocalVariableProxyImpl.clone(name: String, label: String?): LocalVariableProxyImpl {
         return object : LocalVariableProxyImpl(frame, variable), ThisLocalVariable {
             override fun name() = name

idea/jvm-debugger/jvm-debugger-util/src/org/jetbrains/kotlin/idea/debugger/InlineUtils.kt

@@ -22,7 +22,6 @@ fun getInlineDepth(variables: List<LocalVariableProxyImpl>): Int {
         if (depth > 0) {
             return depth
         } else if (name.startsWith(LOCAL_VARIABLE_NAME_PREFIX_INLINE_ARGUMENT)) {
-            // TODO this heuristics doesn't support debugging inlined lambdas inside inline functions.
             return 0
         }
     }
@@ -47,6 +46,15 @@ fun getInlineDepth(variableName: String): Int {
     return depth
 }
 
+fun dropInlineSuffix(name: String): String {
+    val depth = getInlineDepth(name)
+    if (depth == 0) {
+        return name
+    }
+
+    return name.dropLast(depth * INLINE_FUN_VAR_SUFFIX.length)
+}
+
 private fun getLocalVariableNameRegexInlineAware(name: String): Regex {
     val escapedName = Regex.escape(name)
     val escapedSuffix = Regex.escape(INLINE_FUN_VAR_SUFFIX)

idea/testData/debugger/tinyApp/src/evaluate/singleBreakpoint/frame/frameInlineArgumentInsideInlineFun.out

@@ -16,7 +16,7 @@ Compile bytecode for element
    local    = $i$f$inlineFun: int = undefined (sp = null)
    local    = element$iv$iv: double = 1.0 (sp = frameInlineArgumentInsideInlineFun.kt, 13)
    local    = it$iv: int = 1 (sp = null)
-   local    = $i$a$-inlineFun-B$foo$1: int = undefined (sp = null)
+   local    = $i$a$-inlineFun-B$foo$1$iv: int = undefined (sp = null)
 Disconnected from the target VM
 
 Process finished with exit code 0

idea/testData/debugger/tinyApp/src/evaluate/singleBreakpoint/frame/nestedInlineFun2.kt

@@ -0,0 +1,27 @@
+package nestedInlineFun2
+
+fun main() {
+    val a = 1
+    foo {
+        val b = 2
+    }
+}
+
+inline fun foo(block: () -> Unit) {
+    val x = 3
+    bar(1) {
+        val y = 2
+        //Breakpoint!
+        block()
+    }
+}
+
+inline fun bar(count: Int, block: () -> Unit) {
+    var i = count
+    while (i-- > 0) {
+        block()
+    }
+}
+
+// SHOW_KOTLIN_VARIABLES
+// PRINT_FRAME

idea/testData/debugger/tinyApp/src/evaluate/singleBreakpoint/frame/nestedInlineFun2.out

@@ -0,0 +1,10 @@
+LineBreakpoint created at nestedInlineFun2.kt:15
+Run Java
+Connected to the target VM
+nestedInlineFun2.kt:15
+ frame    = main:15, NestedInlineFun2Kt {nestedInlineFun2}
+   local    = x: int = 3 (sp = nestedInlineFun2.kt, 11)
+   local    = y: int = 2 (sp = nestedInlineFun2.kt, 13)
+Disconnected from the target VM
+
+Process finished with exit code 0

idea/tests/org/jetbrains/kotlin/idea/debugger/evaluate/KotlinEvaluateExpressionTestGenerated.java

@@ -905,6 +905,11 @@ public class KotlinEvaluateExpressionTestGenerated extends AbstractKotlinEvaluat
                 runTest("idea/testData/debugger/tinyApp/src/evaluate/singleBreakpoint/frame/nestedInlineFun.kt");
             }
 
+            @TestMetadata("nestedInlineFun2.kt")
+            public void testNestedInlineFun2() throws Exception {
+                runTest("idea/testData/debugger/tinyApp/src/evaluate/singleBreakpoint/frame/nestedInlineFun2.kt");
+            }
+
             @TestMetadata("remapThis.kt")
             public void testRemapThis() throws Exception {
                 runTest("idea/testData/debugger/tinyApp/src/evaluate/singleBreakpoint/frame/remapThis.kt");