Do not generate source links for synthetic elements

Fixes #2544

plugins/base/src/main/kotlin/transformers/pages/sourcelinks/SourceLinksTransformer.kt

@@ -2,6 +2,7 @@ package org.jetbrains.dokka.base.transformers.pages.sourcelinks
 
 import com.intellij.psi.PsiDocumentManager
 import com.intellij.psi.PsiElement
+import com.intellij.psi.SyntheticElement
 import org.jetbrains.dokka.DokkaConfiguration
 import org.jetbrains.dokka.DokkaConfiguration.DokkaSourceSet
 import org.jetbrains.dokka.analysis.DescriptorDocumentableSource
@@ -134,9 +135,13 @@ class SourceLinksTransformer(val context: DokkaContext) : PageTransformer {
         }
 
     private fun PsiElement.lineNumber(): Int? {
-        val doc = PsiDocumentManager.getInstance(project).getDocument(containingFile)
-        // IJ uses 0-based line-numbers; external source browsers use 1-based
-        return doc?.getLineNumber(textRange.startOffset)?.plus(1)
+        return if (this is SyntheticElement) {
+            null // does not actually exist in code, thus no line number
+        } else {
+            val doc = PsiDocumentManager.getInstance(project).getDocument(containingFile)
+            // IJ uses 0-based line-numbers; external source browsers use 1-based
+            return doc?.getLineNumber(textRange.startOffset)?.plus(1)
+        }
     }
 }
 

plugins/base/src/test/kotlin/enums/JavaEnumsTest.kt

@@ -0,0 +1,60 @@
+package enums
+
+import org.jetbrains.dokka.SourceLinkDefinitionImpl
+import org.jetbrains.dokka.base.testApi.testRunner.BaseAbstractTest
+import org.jsoup.Jsoup
+import org.junit.jupiter.api.Test
+import utils.TestOutputWriterPlugin
+import java.net.URL
+import kotlin.test.assertEquals
+
+class JavaEnumsTest : BaseAbstractTest() {
+
+    // Shouldn't try to give source links to synthetic methods (values, valueOf) if any are present
+    // https://github.com/Kotlin/dokka/issues/2544
+    @Test
+    fun `java enum with configured source links should not fail build due to any synthetic methods`() {
+        val configuration = dokkaConfiguration {
+            sourceSets {
+                sourceSet {
+                    sourceRoots = listOf("src/")
+                    sourceLinks = listOf(
+                        SourceLinkDefinitionImpl(
+                            localDirectory = "src/main/java",
+                            remoteUrl = URL("https://github.com/user/repo/tree/master/src/main/java"),
+                            remoteLineSuffix = "#L"
+                        )
+                    )
+                }
+            }
+        }
+
+        val writerPlugin = TestOutputWriterPlugin()
+
+        testInline(
+            """
+            |/src/main/java/basic/JavaEnum.java
+            |package testpackage
+            |
+            |public enum JavaEnum {
+            |    ONE, TWO, THREE
+            |}
+        """.trimMargin(),
+            configuration,
+            pluginOverrides = listOf(writerPlugin)
+        ) {
+            renderingStage = { _, _ ->
+                val enumPage = writerPlugin.writer.contents.getValue("root/testpackage/-java-enum/index.html")
+                val sourceLink = Jsoup.parse(enumPage)
+                    .select("div[data-togglable=Sources]")
+                    .select("a[href]")
+                    .attr("href")
+
+                assertEquals(
+                    "https://github.com/user/repo/tree/master/src/main/java/basic/JavaEnum.java#L3",
+                    sourceLink
+                )
+            }
+        }
+    }
+}

plugins/base/src/test/kotlin/enums/EnumsTest.kt → plugins/base/src/test/kotlin/enums/KotlinEnumsTest.kt

@@ -1,6 +1,7 @@
 package enums
 
 import matchers.content.*
+import org.jetbrains.dokka.SourceLinkDefinitionImpl
 import org.jetbrains.dokka.pages.*
 import org.jetbrains.dokka.base.testApi.testRunner.BaseAbstractTest
 import org.jetbrains.dokka.model.*
@@ -12,8 +13,9 @@ import org.junit.jupiter.api.Test
 import signatures.renderedContent
 import utils.TestOutputWriter
 import utils.TestOutputWriterPlugin
+import java.net.URL
 
-class EnumsTest : BaseAbstractTest() {
+class KotlinEnumsTest : BaseAbstractTest() {
 
     @Test
     fun `should preserve enum source ordering for documentables`() {
@@ -366,4 +368,53 @@ class EnumsTest : BaseAbstractTest() {
             }
         }
     }
+
+    // Shouldn't try to give source links to synthetic methods (values, valueOf) if any are present
+    // Initially reported for Java, making sure it doesn't fail for Kotlin either
+    // https://github.com/Kotlin/dokka/issues/2544
+    @Test
+    fun `kotlin enum with configured source links should not fail the build due to synthetic methods`() {
+        val configuration = dokkaConfiguration {
+            sourceSets {
+                sourceSet {
+                    sourceRoots = listOf("src/")
+                    sourceLinks = listOf(
+                        SourceLinkDefinitionImpl(
+                            localDirectory = "src/main/kotlin",
+                            remoteUrl = URL("https://github.com/user/repo/tree/master/src/main/kotlin"),
+                            remoteLineSuffix = "#L"
+                        )
+                    )
+                }
+            }
+        }
+
+        val writerPlugin = TestOutputWriterPlugin()
+
+        testInline(
+            """
+            |/src/main/kotlin/basic/KotlinEnum.kt
+            |package testpackage
+            |
+            |enum class KotlinEnum {
+            |    ONE, TWO, THREE
+            |}
+        """.trimMargin(),
+            configuration,
+            pluginOverrides = listOf(writerPlugin)
+        ) {
+            renderingStage = { _, _ ->
+                val enumPage = writerPlugin.writer.contents.getValue("root/testpackage/-kotlin-enum/index.html")
+                val sourceLink = Jsoup.parse(enumPage)
+                    .select("div[data-togglable=Sources]")
+                    .select("a[href]")
+                    .attr("href")
+
+                assertEquals(
+                    "https://github.com/user/repo/tree/master/src/main/kotlin/basic/KotlinEnum.kt#L3",
+                    sourceLink
+                )
+            }
+        }
+    }
 }