fix(amazonq): didOpen emits for files already open on IDE start

plugins/amazonq/shared/jetbrains-community/src/software/aws/toolkits/jetbrains/services/amazonq/lsp/textdocument/TextDocumentServiceHandler.kt

@@ -52,6 +52,27 @@ class TextDocumentServiceHandler(
             FileDocumentManagerListener.TOPIC,
             this
         )
+
+        // open files on startup
+        val fileEditorManager = FileEditorManager.getInstance(project)
+        fileEditorManager.openFiles.forEach { file ->
+            handleFileOpened(file)
+        }
+    }
+
+    private fun handleFileOpened(file: VirtualFile) {
+        AmazonQLspService.executeIfRunning(project) { languageServer ->
+            toUriString(file)?.let { uri ->
+                languageServer.textDocumentService.didOpen(
+                    DidOpenTextDocumentParams().apply {
+                        textDocument = TextDocumentItem().apply {
+                            this.uri = uri
+                            text = file.inputStream.readAllBytes().decodeToString()
+                        }
+                    }
+                )
+            }
+        }
     }
 
     override fun beforeDocumentSaving(document: Document) {
@@ -99,18 +120,7 @@ class TextDocumentServiceHandler(
         source: FileEditorManager,
         file: VirtualFile,
     ) {
-        AmazonQLspService.executeIfRunning(project) { languageServer ->
-            toUriString(file)?.let { uri ->
-                languageServer.textDocumentService.didOpen(
-                    DidOpenTextDocumentParams().apply {
-                        textDocument = TextDocumentItem().apply {
-                            this.uri = uri
-                            text = file.inputStream.readAllBytes().decodeToString()
-                        }
-                    }
-                )
-            }
-        }
+        handleFileOpened(file)
     }
 
     override fun fileClosed(

plugins/amazonq/shared/jetbrains-community/tst/software/aws/toolkits/jetbrains/services/amazonq/lsp/textdocument/TextDocumentServiceHandlerTest.kt

@@ -9,6 +9,7 @@ import com.intellij.openapi.application.ApplicationManager
 import com.intellij.openapi.components.serviceIfCreated
 import com.intellij.openapi.editor.Document
 import com.intellij.openapi.fileEditor.FileDocumentManager
+import com.intellij.openapi.fileEditor.FileEditorManager
 import com.intellij.openapi.project.Project
 import com.intellij.openapi.vfs.VirtualFile
 import com.intellij.openapi.vfs.newvfs.events.VFileContentChangeEvent
@@ -43,6 +44,7 @@ import java.util.concurrent.CompletableFuture
 
 class TextDocumentServiceHandlerTest {
     private lateinit var project: Project
+    private lateinit var mockFileEditorManager: FileEditorManager
     private lateinit var mockLanguageServer: AmazonQLanguageServer
     private lateinit var mockTextDocumentService: TextDocumentService
     private lateinit var sut: TextDocumentServiceHandler
@@ -90,6 +92,11 @@ class TextDocumentServiceHandlerTest {
         every { messageBus.connect(any<Disposable>()) } returns mockConnection
         every { mockConnection.subscribe(any(), any()) } just runs
 
+        // Mock FileEditorManager
+        mockFileEditorManager = mockk<FileEditorManager>()
+        every { mockFileEditorManager.openFiles } returns emptyArray()
+        every { project.getService(FileEditorManager::class.java) } returns mockFileEditorManager
+
         sut = TextDocumentServiceHandler(project, mockk())
     }
 
@@ -126,6 +133,25 @@ class TextDocumentServiceHandlerTest {
         }
     }
 
+    @Test
+    fun `didOpen runs on service init`() = runTest {
+        val uri = URI.create("file:///test/path/file.txt")
+        val content = "test content"
+        val file = createMockVirtualFile(uri, content)
+
+        every { mockFileEditorManager.openFiles } returns arrayOf(file)
+
+        sut = TextDocumentServiceHandler(project, mockk())
+
+        val paramsSlot = slot<DidOpenTextDocumentParams>()
+        verify { mockTextDocumentService.didOpen(capture(paramsSlot)) }
+
+        with(paramsSlot.captured.textDocument) {
+            assertEquals(normalizeFileUri(uri.toString()), this.uri)
+            assertEquals(content, text)
+        }
+    }
+
     @Test
     fun `didOpen runs on fileOpened`() = runTest {
         // Create test file