Fix build reports when no kotlin task is executed

#KT-58313: Fixed

compiler/build-tools/kotlin-build-statistics/src/org/jetbrains/kotlin/build/report/statistics/file/FileReportService.kt

@@ -78,7 +78,7 @@ class FileReportService(
         // a bit unfamiliar.
         // TODO: If it is confusing, consider renaming "tasks" to "build operations" in this class.
         printBuildInfo(startParameters, failureMessages)
-        if (printMetrics) {
+        if (printMetrics && statisticsData.isNotEmpty()) {
             printMetrics(
                 statisticsData.map { it.buildTimesMetrics }.reduce { agg, value ->
                     (agg.keys + value.keys).associateWith { (agg[it] ?: 0) + (value[it] ?: 0) }

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/kotlin/org/jetbrains/kotlin/gradle/BuildReportsIT.kt

@@ -12,9 +12,8 @@ import org.jetbrains.kotlin.gradle.report.BuildReportType
 import org.jetbrains.kotlin.gradle.testbase.*
 import org.junit.jupiter.api.DisplayName
 import java.io.ObjectInputStream
+import java.nio.file.Path
 import kotlin.io.path.*
-import kotlin.test.assertEquals
-import kotlin.test.assertNotNull
 import kotlin.test.assertTrue
 
 @DisplayName("Build reports")
@@ -25,6 +24,9 @@ class BuildReportsIT : KGPBaseTest() {
             buildReport = listOf(BuildReportType.FILE)
         )
 
+    private val GradleProject.reportFile: Path
+        get() = projectPath.getSingleFileInDir("build/reports/kotlin-build")
+
     @DisplayName("Build report is created")
     @GradleTest
     fun testBuildReportSmokeTest(gradleVersion: GradleVersion) {
@@ -56,26 +58,23 @@ class BuildReportsIT : KGPBaseTest() {
             build("assemble") {
                 assertBuildReportPathIsPrinted()
             }
-            val reportFolder = projectPath.resolve("build/reports/kotlin-build").toFile()
-            val reports = reportFolder.listFiles()
-            assertNotNull(reports)
-            assertEquals(1, reports.size)
-            val report = reports[0].readText()
-
             //Should contains build metrics for all compile kotlin tasks
-            assertTrue { report.contains("Time metrics:") }
-            assertTrue { report.contains("Run compilation:") }
-            assertTrue { report.contains("Incremental compilation in daemon:") }
-            assertTrue { report.contains("Size metrics:") }
-            assertTrue { report.contains("Total size of the cache directory:") }
-            assertTrue { report.contains("Total compiler iteration:") }
-            assertTrue { report.contains("ABI snapshot size:") }
-            //for non-incremental builds
-            assertTrue { report.contains("Build attributes:") }
-            assertTrue { report.contains("REBUILD_REASON:") }
-            //gc metrics
-            assertTrue {report.contains("GC count:")}
-            assertTrue {report.contains("GC time:")}
+            assertFileContains(
+                reportFile,
+                "Time metrics:",
+                "Run compilation:",
+                "Incremental compilation in daemon:",
+                "Size metrics:",
+                "Total size of the cache directory:",
+                "Total compiler iteration:",
+                "ABI snapshot size:",
+                //for non-incremental builds
+                "Build attributes:",
+                "REBUILD_REASON:",
+                //gc metrics
+                "GC count:",
+                "GC time:",
+            )
         }
     }
 
@@ -86,14 +85,26 @@ class BuildReportsIT : KGPBaseTest() {
             build("assemble") {
                 assertBuildReportPathIsPrinted()
             }
-            val reportFolder = projectPath.resolve("build/reports/kotlin-build").toFile()
-            val reports = reportFolder.listFiles()
-            assertNotNull(reports)
-            assertEquals(1, reports.size)
-            val report = reports[0].readText()
-            assertTrue { report.contains("Compiler code analysis:") }
-            assertTrue { report.contains("Compiler code generation:") }
-            assertTrue { report.contains("Compiler initialization time:") }
+            assertFileContains(
+                reportFile,
+                "Compiler code analysis:",
+                "Compiler code generation:",
+                "Compiler initialization time:",
+            )
+        }
+    }
+
+    @DisplayName("with no kotlin task executed")
+    @GradleTest
+    fun testFileReportWithoutKotlinTask(gradleVersion: GradleVersion) {
+        project("simpleProject", gradleVersion) {
+            build("assemble", "--dry-run") {
+                assertBuildReportPathIsPrinted()
+            }
+            assertFileContains(
+                reportFile,
+                "No Kotlin task was run",
+            )
         }
     }
 
@@ -180,18 +191,20 @@ class BuildReportsIT : KGPBaseTest() {
         project("simpleProject", gradleVersion) {
 
             val lookupsTab = projectPath.resolve("build/kotlin/compileKotlin/cacheable/caches-jvm/lookups/lookups.tab")
-            buildGradle.appendText("""
-                tasks.named("compileKotlin") {
-                    doLast {
-                        new File("${lookupsTab.toUri().path}").write("Invalid contents")
+            buildGradle.appendText(
+                """
+                    tasks.named("compileKotlin") {
+                        doLast {
+                            new File("${lookupsTab.toUri().path}").write("Invalid contents")
+                        }
                     }
-                }
-            """.trimIndent())
+                """.trimIndent()
+            )
             build("compileKotlin") {
                 assertTrue { projectPath.resolve(kotlinErrorPath).listDirectoryEntries().isEmpty() }
             }
             val kotlinFile = kotlinSourcesDir().resolve("helloWorld.kt")
-            kotlinFile.modify { it.replace("ArrayList","skjfghsjk") }
+            kotlinFile.modify { it.replace("ArrayList", "skjfghsjk") }
             buildAndFail("compileKotlin") {
                 val buildErrorDir = projectPath.resolve(kotlinErrorPath).toFile()
                 val files = buildErrorDir.listFiles()
@@ -219,7 +232,7 @@ class BuildReportsIT : KGPBaseTest() {
                 assertTrue { projectPath.resolve(kotlinErrorPath).listDirectoryEntries().isEmpty() }
             }
             val kotlinFile = kotlinSourcesDir().resolve("helloWorld.kt")
-            kotlinFile.modify { it.replace("ArrayList","skjfghsjk") }
+            kotlinFile.modify { it.replace("ArrayList", "skjfghsjk") }
             buildAndFail("compileKotlin") {
                 assertTrue { projectPath.resolve(kotlinErrorPath).listDirectoryEntries().isEmpty() }
             }

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/kotlin/org/jetbrains/kotlin/gradle/FusStatisticsIT.kt

@@ -10,10 +10,7 @@ import org.jetbrains.kotlin.gradle.testbase.GradleTest
 import org.junit.jupiter.api.DisplayName
 import org.jetbrains.kotlin.gradle.testbase.*
 import org.jetbrains.kotlin.gradle.util.replaceText
-import org.jetbrains.kotlin.test.KtAssert.fail
-import java.nio.file.Files
 import java.nio.file.Path
-import kotlin.streams.asSequence
 
 @DisplayName("FUS statistic")
 class FusStatisticsIT : KGPBaseTest() {
@@ -62,13 +59,7 @@ class FusStatisticsIT : KGPBaseTest() {
     }
 
     private val GradleProject.fusStatisticsPath: Path
-        get() {
-            val statisticsDir = projectPath.resolve("kotlin-profile")
-            return Files.list(statisticsDir).use {
-                val files = it.asSequence().toList()
-                files.singleOrNull() ?: fail("The directory must contain a single statistics file, but got: $files")
-            }
-        }
+        get() = projectPath.getSingleFileInDir("kotlin-profile")
 
     @DisplayName("general fields")
     @GradleTest

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/kotlin/org/jetbrains/kotlin/gradle/testbase/pathHelpers.kt

@@ -11,6 +11,7 @@ import java.nio.file.attribute.BasicFileAttributes
 import kotlin.io.path.*
 import kotlin.streams.asSequence
 import kotlin.streams.toList
+import kotlin.test.fail
 
 /**
  * Find the file with given [name] in current [Path].
@@ -128,3 +129,15 @@ fun TestProject.sourceFilesRelativeToProject(
             it.relativeTo(projectPath)
         }
 }
+
+/**
+ * Returns a single file located in the [relativePath] subdirectory. If no file or more than one file is found an assertion error will be thrown.
+ */
+fun Path.getSingleFileInDir(relativePath: String): Path {
+    val path = resolve(relativePath)
+    return Files.list(path).use {
+        val files = it.asSequence().toList()
+        files.singleOrNull() ?: fail("The directory must contain a single file, but got: $files")
+    }
+}
+