From 02ddc0782ae16e72c037e488bdafa20165176407 Mon Sep 17 00:00:00 2001
From: nickreid <nickreid@google.com>
Date: Mon, 15 Apr 2024 09:50:50 -0700
Subject: [PATCH] Emit a parsing error for calls with multiple trailing lambdas

---
 .../ktfmt/format/KotlinInputAstVisitor.kt     | 18 +++++++++------
 .../com/facebook/ktfmt/format/ParseError.kt   | 22 +++++++++++++++++--
 .../java/com/facebook/ktfmt/cli/MainTest.kt   | 12 ++++++++++
 3 files changed, 43 insertions(+), 9 deletions(-)

diff --git a/core/src/main/java/com/facebook/ktfmt/format/KotlinInputAstVisitor.kt b/core/src/main/java/com/facebook/ktfmt/format/KotlinInputAstVisitor.kt
index b233074f..da62912e 100644
--- a/core/src/main/java/com/facebook/ktfmt/format/KotlinInputAstVisitor.kt
+++ b/core/src/main/java/com/facebook/ktfmt/format/KotlinInputAstVisitor.kt
@@ -771,13 +771,17 @@ class KotlinInputAstVisitor(
           }
         }
       }
-      if (lambdaArguments.isNotEmpty()) {
-        builder.space()
-        visitArgumentInternal(
-            lambdaArguments.single(),
-            wrapInBlock = false,
-            brokeBeforeBrace = brokeBeforeBrace,
-        )
+      when (lambdaArguments.size) {
+        0 -> {}
+        1 -> {
+          builder.space()
+          visitArgumentInternal(
+              lambdaArguments.single(),
+              wrapInBlock = false,
+              brokeBeforeBrace = brokeBeforeBrace,
+          )
+        }
+        else -> throw ParseError("Maximum one trailing lambda is allowed", lambdaArguments[1])
       }
     }
   }
diff --git a/core/src/main/java/com/facebook/ktfmt/format/ParseError.kt b/core/src/main/java/com/facebook/ktfmt/format/ParseError.kt
index 216dfb6a..b116e210 100644
--- a/core/src/main/java/com/facebook/ktfmt/format/ParseError.kt
+++ b/core/src/main/java/com/facebook/ktfmt/format/ParseError.kt
@@ -17,7 +17,25 @@
 package com.facebook.ktfmt.format
 
 import org.jetbrains.kotlin.com.intellij.openapi.util.text.LineColumn
+import org.jetbrains.kotlin.com.intellij.psi.PsiElement
 
 class ParseError(val errorDescription: String, val lineColumn: LineColumn) :
-    IllegalArgumentException(
-        "${lineColumn.line + 1}:${lineColumn.column + 1}: error: $errorDescription")
+  IllegalArgumentException(
+    "${lineColumn.line + 1}:${lineColumn.column + 1}: error: $errorDescription"
+  ) {
+
+  constructor(
+    errorDescription: String,
+    element: PsiElement,
+  ) : this(errorDescription, positionOf(element))
+
+  companion object {
+    private fun positionOf(element: PsiElement): LineColumn {
+      val doc = element.containingFile.viewProvider.document
+      val offset = element.textOffset
+      val lineZero = doc.getLineNumber(offset)
+      val colZero = offset - doc.getLineStartOffset(lineZero)
+      return LineColumn.of(lineZero, colZero)
+    }
+  }
+}
diff --git a/core/src/test/java/com/facebook/ktfmt/cli/MainTest.kt b/core/src/test/java/com/facebook/ktfmt/cli/MainTest.kt
index 6e207fe7..925ad271 100644
--- a/core/src/test/java/com/facebook/ktfmt/cli/MainTest.kt
+++ b/core/src/test/java/com/facebook/ktfmt/cli/MainTest.kt
@@ -159,6 +159,18 @@ class MainTest {
     assertThat(err.toString(testCharset)).contains("foo.kt:1:14: error: ")
   }
 
+  @Test
+  fun `Parsing error for multiple trailing lambdas`() {
+    val fooBar = root.resolve("foo.kt")
+    fooBar.writeText("val x = foo(bar { } { zap = 2 })")
+    val returnValue =
+        Main(emptyInput, PrintStream(out), PrintStream(err), arrayOf(fooBar.toString())).run()
+
+    assertThat(returnValue).isEqualTo(1)
+    assertThat(err.toString(testCharset))
+        .contains("foo.kt:1:21: error: Maximum one trailing lambda is allowed")
+  }
+
   @Test
   fun `all files in args are processed, even if one of them has an error`() {
     val file1 = root.resolve("file1.kt")