From dd63ac7d446b152fcfe953f28d42f04900e018bd Mon Sep 17 00:00:00 2001
From: Cadence Ember <cadence@disroot.org>
Date: Wed, 12 Mar 2025 16:01:36 +1300
Subject: [PATCH] New error trace stringifier

---
 src/d2m/event-dispatcher.js | 23 ++++++-------
 src/m2d/event-dispatcher.js | 67 ++++++++++++++++++++++++++++++++++---
 test/test.js                | 18 +++++-----
 test/web.js                 |  2 +-
 4 files changed, 85 insertions(+), 25 deletions(-)

diff --git a/src/d2m/event-dispatcher.js b/src/d2m/event-dispatcher.js
index fdb6c93..b98abfc 100644
--- a/src/d2m/event-dispatcher.js
+++ b/src/d2m/event-dispatcher.js
@@ -35,6 +35,8 @@ const speedbump = sync.require("./actions/speedbump")
 const retrigger = sync.require("./actions/retrigger")
 /** @type {import("./actions/set-presence")} */
 const setPresence = sync.require("./actions/set-presence")
+/** @type {import("../m2d/event-dispatcher")} */
+const matrixEventDispatcher = sync.require("../m2d/event-dispatcher")
 
 /** @type {any} */ // @ts-ignore bad types from semaphore
 const Semaphore = require("@chriscdn/promise-semaphore")
@@ -66,22 +68,19 @@ module.exports = {
 		const roomID = select("channel_room", "room_id", {channel_id: channelID}).pluck().get()
 		if (!roomID) return
 
-		let stackLines = null
-		if (e.stack) {
-			stackLines = e.stack.split("\n")
-			let cloudstormLine = stackLines.findIndex(l => l.includes("/node_modules/cloudstorm/"))
-			if (cloudstormLine !== -1) {
-				stackLines = stackLines.slice(0, cloudstormLine - 2)
-			}
-		}
-
 		const builder = new mxUtils.MatrixStringBuilder()
 		builder.addLine("\u26a0 Bridged event from Discord not delivered", "\u26a0 <strong>Bridged event from Discord not delivered</strong>")
 		builder.addLine(`Gateway event: ${gatewayMessage.t}`)
-		builder.addLine(e.toString())
-		if (stackLines) {
-			builder.addLine(`Error trace:\n${stackLines.join("\n")}`, `<details><summary>Error trace</summary><pre>${stackLines.join("\n")}</pre></details>`)
+
+		let errorIntroLine = e.toString()
+		if (e.cause) {
+			errorIntroLine += ` (cause: ${e.cause})`
 		}
+		builder.addLine(errorIntroLine)
+
+		const stack = matrixEventDispatcher.stringifyErrorStack(e)
+		builder.addLine(`Error trace:\n${stack}`, `<details><summary>Error trace</summary><pre>${stack}</pre></details>`)
+
 		builder.addLine("", `<details><summary>Original payload</summary><pre>${util.inspect(gatewayMessage.d, false, 4, false)}</pre></details>`)
 		await api.sendEvent(roomID, "m.room.message", {
 			...builder.get(),
diff --git a/src/m2d/event-dispatcher.js b/src/m2d/event-dispatcher.js
index 5f8cb2b..1bc97de 100644
--- a/src/m2d/event-dispatcher.js
+++ b/src/m2d/event-dispatcher.js
@@ -28,6 +28,58 @@ const {reg} = require("../matrix/read-registration")
 
 let lastReportedEvent = 0
 
+/**
+ * This function is adapted from Evan Kaufman's fantastic work.
+ * The original function and my adapted function are both MIT licensed.
+ * @url https://github.com/EvanK/npm-loggable-error/
+ * @param {number} [depth]
+ * @returns {string}
+*/
+function stringifyErrorStack(err, depth = 0) {
+	let collapsed = " ".repeat(depth);
+	if (!(err instanceof Error)) {
+		return collapsed + err
+	}
+
+	// add full stack trace if one exists, otherwise convert to string
+	let stackLines = ( err?.stack ?? `${err}` ).replace(/^/gm, " ".repeat(depth)).trim().split("\n")
+	let cloudstormLine = stackLines.findIndex(l => l.includes("/node_modules/cloudstorm/"))
+	if (cloudstormLine !== -1) {
+		stackLines = stackLines.slice(0, cloudstormLine - 2)
+	}
+	collapsed += stackLines.join("\n")
+
+	const props = Object.getOwnPropertyNames(err).filter(p => !["message", "stack"].includes(p))
+
+	// only break into object notation if we have addtl props to dump
+	if (props.length) {
+		const dedent = " ".repeat(depth);
+		const indent = " ".repeat(depth + 2);
+
+		collapsed += " {\n";
+
+		// loop and print each (indented) prop name
+		for (let property of props) {
+			collapsed += `${indent}[${property}]: `;
+
+			// if another error object, stringify it too
+			if (err[property] instanceof Error) {
+				collapsed += stringifyErrorStack(err[property], depth + 2).trimStart();
+			}
+			// otherwise stringify as JSON
+			else {
+				collapsed += JSON.stringify(err[property]);
+			}
+
+			collapsed += "\n";
+		}
+
+		collapsed += `${dedent}}\n`;
+	}
+
+	return collapsed;
+}
+
 function guard(type, fn) {
 	return async function(event, ...args) {
 		try {
@@ -39,7 +91,12 @@ function guard(type, fn) {
 			if (Date.now() - lastReportedEvent < 5000) return
 			lastReportedEvent = Date.now()
 
-			const cloudflareErrorTitle = e.toString().match(/<!DOCTYPE html>.*?<title>discord\.com \| ([^<]*)<\/title>/s)?.[1]
+			let errorIntroLine = e.toString()
+			if (e.cause) {
+				errorIntroLine += ` (cause: ${e.cause})`
+			}
+
+			const cloudflareErrorTitle = errorIntroLine.match(/<!DOCTYPE html>.*?<title>discord\.com \| ([^<]*)<\/title>/s)?.[1]
 			if (cloudflareErrorTitle) {
 				return api.sendEvent(event.room_id, "m.room.message", {
 					msgtype: "m.text",
@@ -53,16 +110,16 @@ function guard(type, fn) {
 				})
 			}
 
-			let stackLines = e.stack.split("\n")
+			const stack = stringifyErrorStack(e)
 			api.sendEvent(event.room_id, "m.room.message", {
 				msgtype: "m.text",
 				body: "\u26a0 Matrix event not delivered to Discord. See formatted content for full details.",
 				format: "org.matrix.custom.html",
 				formatted_body: "\u26a0 <strong>Matrix event not delivered to Discord</strong>"
 					+ `<br>Event type: ${type}`
-					+ `<br>${e.toString()}`
+					+ `<br>${errorIntroLine}`
 					+ `<br><details><summary>Error trace</summary>`
-					+ `<pre>${stackLines.join("\n")}</pre></details>`
+					+ `<pre>${stack}</pre></details>`
 					+ `<details><summary>Original payload</summary>`
 					+ `<pre>${util.inspect(event, false, 4, false)}</pre></details>`,
 				"moe.cadence.ooye.error": {
@@ -297,3 +354,5 @@ async event => {
 		db.prepare("UPDATE member_cache SET power_level = ? WHERE room_id = ? AND mxid = ?").run(newPower[mxid] || 0, event.room_id, mxid)
 	}
 }))
+
+module.exports.stringifyErrorStack = stringifyErrorStack
diff --git a/test/test.js b/test/test.js
index 35c12ed..2d02cbb 100644
--- a/test/test.js
+++ b/test/test.js
@@ -29,7 +29,7 @@ reg.ooye.bridge_origin = "https://bridge.example.org"
 const sync = new HeatSync({watchFS: false})
 
 const discord = {
-	// @ts-ignore - only ignore guilds, because my data dump is missing random properties
+	// @ts-ignore - ignore guilds, because my data dump is missing random properties
 	guilds: new Map([
 		[data.guild.general.id, data.guild.general],
 		[data.guild.fna.id, data.guild.fna],
@@ -43,6 +43,7 @@ const discord = {
 	application: {
 		id: "684280192553844747"
 	},
+	// @ts-ignore - ignore channels, because my data dump is missing random properties
 	channels: new Map([
 		[data.channel.general.id, data.channel.general],
 		[data.channel.updates.id, data.channel.updates],
@@ -127,6 +128,13 @@ file._actuallyUploadDiscordFileToMxc = function(url, res) { throw new Error(`Not
 
 	require("./addbot.test")
 	require("../src/db/orm.test")
+	require("../src/web/server.test")
+	require("../src/web/routes/download-discord.test")
+	require("../src/web/routes/download-matrix.test")
+	require("../src/web/routes/guild.test")
+	require("../src/web/routes/guild-settings.test")
+	require("../src/web/routes/link.test")
+	require("../src/web/routes/log-in-with-matrix.test")
 	require("../src/discord/utils.test")
 	require("../src/matrix/kstate.test")
 	require("../src/matrix/api.test")
@@ -147,6 +155,7 @@ file._actuallyUploadDiscordFileToMxc = function(url, res) { throw new Error(`Not
 	require("../src/d2m/converters/remove-reaction.test")
 	require("../src/d2m/converters/thread-to-announcement.test")
 	require("../src/d2m/converters/user-to-mxid.test")
+	require("../src/m2d/event-dispatcher.test")
 	require("../src/m2d/converters/diff-pins.test")
 	require("../src/m2d/converters/event-to-message.test")
 	require("../src/m2d/converters/emoji.test")
@@ -157,11 +166,4 @@ file._actuallyUploadDiscordFileToMxc = function(url, res) { throw new Error(`Not
 	require("../src/discord/interactions/permissions.test")
 	require("../src/discord/interactions/privacy.test")
 	require("../src/discord/interactions/reactions.test")
-	require("../src/web/server.test")
-	require("../src/web/routes/download-discord.test")
-	require("../src/web/routes/download-matrix.test")
-	require("../src/web/routes/guild.test")
-	require("../src/web/routes/guild-settings.test")
-	require("../src/web/routes/link.test")
-	require("../src/web/routes/log-in-with-matrix.test")
 })()
diff --git a/test/web.js b/test/web.js
index 0595a96..eb2b876 100644
--- a/test/web.js
+++ b/test/web.js
@@ -96,7 +96,7 @@ class Router {
 
 const router = new Router()
 
-passthrough.as = {router}
+passthrough.as = {router, on() {}}
 
 module.exports.router = router
 module.exports.test = test