Merge pull request #15 from andipabst/fix/elm-format

Show elm-format syntax error notification

Author: ahankinson

src/main/kotlin/org/elm/workspace/commandLineTools/ElmFormatCLI.kt

@@ -45,6 +45,11 @@ class ElmFormatCLI(private val elmFormatExecutablePath: Path) {
         class UnknownFailure(msg: String? = null, cause: Throwable?) : ElmFormatResult(msg ?: "Something went wrong running elm-format", cause)
     }
 
+    private fun isBadSyntaxErrorMessage(msg: String): Boolean {
+        return msg.contains("SYNTAX PROBLEM", ignoreCase = true) // Elm-format 0.8.4 and below
+                || msg.contains("Unable to parse file")  // Elm-format 0.8.5 and above
+    }
+
     fun formatDocumentAndSetText(project: Project, document: Document, version: Version, addToUndoStack: Boolean): ElmFormatResult {
         val processOutput = try {
             ProgressManager.getInstance().runProcessWithProgressSynchronously<ProcessOutput, ExecutionException>({
@@ -59,7 +64,12 @@ class ElmFormatCLI(private val elmFormatExecutablePath: Path) {
             }
         }
 
-        if (processOutput.isNotSuccess) return ElmFormatResult.UnknownFailure("Process output exit code was non-zero", cause = null)
+        if (processOutput.isNotSuccess) {
+            if (isBadSyntaxErrorMessage(processOutput.stderr)) {
+                return ElmFormatResult.BadSyntax()
+            }
+            return ElmFormatResult.UnknownFailure("Process output exit code was non-zero", cause = null)
+        }
 
         val formatted = processOutput.stdout
         val source = document.text

src/test/kotlin/org/elm/ide/actions/ElmExternalFormatActionTest.kt

@@ -1,9 +1,12 @@
 package org.elm.ide.actions
 
+import com.intellij.notification.Notification
+import com.intellij.notification.Notifications
 import com.intellij.openapi.actionSystem.CommonDataKeys
 import com.intellij.openapi.command.undo.UndoManager
 import com.intellij.openapi.fileEditor.FileDocumentManager
 import com.intellij.openapi.fileEditor.FileEditorManager
+import com.intellij.openapi.util.Ref
 import com.intellij.openapi.vfs.VirtualFile
 import com.intellij.testFramework.MapDataContext
 import com.intellij.testFramework.TestActionEvent
@@ -55,6 +58,36 @@ class ElmExternalFormatActionTest : ElmWorkspaceTestBase() {
         TestCase.assertEquals(expected, document.text)
     }
 
+    @Test
+    fun `test elm-format action on a file with syntax errors`() {
+        val originalCode = """
+                    module Main exposing (f)
+
+
+                    f x =
+                """.trimIndent()
+
+
+        buildProject {
+            project("elm.json", manifestElm19)
+            dir("src") {
+                elm("Main.elm", originalCode)
+            }
+        }
+
+        val file = myFixture.configureFromTempProjectFile("src/Main.elm").virtualFile
+        val document = FileDocumentManager.getInstance().getDocument(file)!!
+
+        val ref = connectToBusAndGetNotificationRef()
+        reformat(file)
+        
+        TestCase.assertEquals(originalCode, document.text)
+
+        TestCase.assertEquals("elm-format encountered syntax errors that it could not fix", ref.get().content)
+        TestCase.assertEquals(1, ref.get().actions.size)
+        TestCase.assertEquals("Show Errors", ref.get().actions.first().templatePresentation.text)
+    }
+
     @Test
     fun `test elm-format action shouldn't be active on non-elm files`() {
         buildProject {
@@ -116,6 +149,16 @@ class ElmExternalFormatActionTest : ElmWorkspaceTestBase() {
         return Pair(action, event)
     }
 
+    private fun connectToBusAndGetNotificationRef(): Ref<Notification> {
+        val notificationRef = Ref<Notification>()
+        project.messageBus.connect(testRootDisposable).subscribe(Notifications.TOPIC,
+            object : Notifications {
+                override fun notify(notification: Notification) =
+                    notificationRef.set(notification)
+            })
+        return notificationRef
+    }
+
 }