Fix version parser for versions without status "1.4-M1-42-IJ2020.1-1".

idea/src/org/jetbrains/kotlin/idea/KotlinPluginCompatibilityVerifier.kt

@@ -9,7 +9,6 @@ import com.intellij.openapi.application.ApplicationInfo
 import com.intellij.openapi.ui.Messages
 import com.intellij.util.PlatformUtils
 import com.intellij.util.text.nullize
-import org.intellij.lang.annotations.RegExp
 
 object KotlinPluginCompatibilityVerifier {
     @JvmStatic
@@ -29,7 +28,7 @@ object KotlinPluginCompatibilityVerifier {
 data class KotlinPluginVersion(
     val kotlinVersion: String, // 1.2.3
     val milestone: String?, // M1
-    val status: String, // release, eap, rc
+    val status: String?, // release, eap, rc
     val buildNumber: String?, // 53
     val platformVersion: PlatformVersion,
     val patchNumber: String // usually '1'
@@ -38,7 +37,7 @@ data class KotlinPluginVersion(
         private const val KOTLIN_VERSION_REGEX_STRING =
             "^([\\d.]+)" +                // Version number, like 1.3.50
                     "(?:-(M\\d+))?" +     // (Optional) M-release, like M2
-                    "-([A-Za-z]+)" +      // status, like 'eap/dev/release'
+                    "(?:-([A-Za-z]+))?" + // (Optional) status, like 'eap/dev/release'
                     "(?:-(\\d+))?" +      // (Optional) buildNumber (absent for 'release')
                     "-([A-Za-z0-9.]+)" +  // Platform version, like Studio4.0.1
                     "-(\\d+)$"            // Tooling update, like '-1'

idea/tests/org/jetbrains/kotlin/test/CompatibilityVerifierVersionComparisonTest.kt

@@ -43,6 +43,23 @@ class CompatibilityVerifierVersionComparisonTest : LightPlatformTestCase() {
         assertEquals("1", version.patchNumber)
     }
 
+    fun testMilestoneVersionWithoutStatus() {
+        val version = KotlinPluginVersion.parse("1.4-M1-42-IJ2020.1-1") ?: throw AssertionError("Version should not be null")
+
+        assertEquals("1.4", version.kotlinVersion)
+        assertEquals("M1", version.milestone)
+        assertEquals("42", version.buildNumber)
+        assertEquals(PlatformVersion.Platform.IDEA, version.platformVersion.platform)
+        assertEquals("2020.1", version.platformVersion.version)
+        assertEquals("1", version.patchNumber)
+    }
+
+    fun testInvalidVersion() {
+        val version = KotlinPluginVersion.parse("1.4-release-M5-IJ2020.1-1")
+
+        assertNull(version)
+    }
+
     fun testPlatformVersionParsing() {
         PlatformVersion.getCurrent() ?: throw AssertionError("Version should not be null")
     }