Fix problems with outgoing messages

1. Don't set the "own message" promise to null on resolve, as other
   places may still be awaiting on it afterwards
2. Retry pressing "Enter" to send a message if it doesn't work on the
   first try, which can happen for some reason

puppet/src/contentscript.js

@@ -95,6 +95,7 @@ class MautrixController {
 		this.pinAppearObserver = null
 		this.ownID = null
 
+		this.ownMsgPromise = Promise.resolve(-1)
 		this._promiseOwnMsgReset()
 	}
 
@@ -474,13 +475,20 @@ class MautrixController {
 		}, timeoutLimitMillis)
 	}
 
+	/**
+	 * Check if we're waiting for a Matrix-sent message to resolve.
+	 */
+	_isWaitingForOwnMessage() {
+		return !!this.promiseOwnMsgResolve
+	}
+
 	/**
 	 * Wait for a user-sent message to finish getting sent.
 	 *
 	 * @return {Promise<number>} - The ID of the sent message.
 	 */
 	async waitForOwnMessage() {
-		return this.ownMsgPromise ? await this.ownMsgPromise : -1
+		return await this.ownMsgPromise
 	}
 
 	/**
@@ -867,7 +875,7 @@ class MautrixController {
 	addChatListObserver() {
 		this.removeChatListObserver()
 		this.chatListObserver = new MutationObserver(async (mutations) => {
-			if (this.ownMsgPromise) {
+			if (this._isWaitingForOwnMessage()) {
 				// Wait for pending sent messages to be resolved before responding to mutations
 				try {
 					await this.ownMsgPromise
@@ -1213,8 +1221,7 @@ class MautrixController {
 	}
 
 	_observeOwnMessage(ownMsg) {
-		if (!this.ownMsgPromise) {
+		if (!this._isWaitingForOwnMessage()) {
-			// Not waiting for a pending sent message
 			return null
 		}
 
@@ -1299,7 +1306,6 @@ class MautrixController {
 	}
 
 	_promiseOwnMsgReset() {
-		this.ownMsgPromise = null
 		this.promiseOwnMsgSuccessSelector = null
 		this.promiseOwnMsgFailureSelector = null
 		this.promiseOwnMsgResolve = null

puppet/src/puppet.js

@@ -790,7 +790,18 @@ export default class MessagesPuppeteer {
 			// Setting its innerText directly works fine though...
 			await input.click()
 			await input.evaluate((e, text) => e.innerText = text, text)
+			while (true) {
 				await input.press("Enter")
+				try {
+					await this.page.waitForFunction(
+						e => e.innerText == "",
+						{timeout: 500},
+						input)
+					break
+				} catch (e) {
+					this.error(`Failed to press Enter when sending message, try again (${e})`)
+				}
+			}
 		})
 
 		return await this._waitForSentMessage(chatID)