V3 backport: fix: improve error message when the entrypoint is incorrect

.changeset/brave-geckos-juggle.md

@@ -0,0 +1,5 @@
+---
+"wrangler": patch
+---
+
+fix: improve error message when the entrypoint is incorrect

packages/wrangler/src/__tests__/deploy.test.ts

@@ -7122,9 +7122,7 @@ addEventListener('fetch', event => {});`
 
 			await expect(runWrangler("deploy")).rejects
 				.toThrowErrorMatchingInlineSnapshot(`
-				[Error: The expected output file at "." was not found after running custom build: node -e "4+4;".
-				The \`main\` property in your wrangler.toml file should point to the file generated by the custom build.
-				The provided entry-point path, ".", points to a directory, rather than a file.
+				[Error: The provided entry-point path, ".", points to a directory, rather than a file.
 
 				Did you mean to set the main field to one of:
 				\`\`\`
@@ -7137,11 +7135,8 @@ addEventListener('fetch', event => {});`
 				"
 			`);
 			expect(std.err).toMatchInlineSnapshot(`
-				"X [ERROR] The expected output file at \\".\\" was not found after running custom build: node -e \\"4+4;\\".
+				"X [ERROR] The provided entry-point path, \\".\\", points to a directory, rather than a file.
 
-				  The \`main\` property in your wrangler.toml file should point to the file generated by the custom
-				  build.
-				  The provided entry-point path, \\".\\", points to a directory, rather than a file.
 
 				  Did you mean to set the main field to one of:
 				  \`\`\`

packages/wrangler/src/__tests__/startup-profiling.test.ts

@@ -61,7 +61,12 @@ describe("wrangler check startup", () => {
 		await expect(
 			runWrangler("check startup --args 'abc'")
 		).rejects.toThrowErrorMatchingInlineSnapshot(
-			`[Error: The entry-point file at "abc" was not found.]`
+			`
+			[Error: The entry-point file at "abc" was not found.
+
+			This might mean that your entry-point file needs to be generated (which is the general case when a framework is being used).
+			If that's the case please run your project's build command and try again.]
+		`
 		);
 	});
 

packages/wrangler/src/deployment-bundle/run-custom-build.ts

@@ -3,6 +3,7 @@ import path from "node:path";
 import { Writable } from "node:stream";
 import chalk from "chalk";
 import { execaCommand } from "execa";
+import dedent from "ts-dedent";
 import { configFileName } from "../config";
 import { UserError } from "../errors";
 import { logger } from "../logger";
@@ -63,15 +64,11 @@ export async function runCustomBuild(
 		assertEntryPointExists(
 			expectedEntryAbsolute,
 			expectedEntryRelative,
-			`The expected output file at "${expectedEntryRelative}" was not found after running custom build: ${build.command}.\n` +
-				`The \`main\` property in your ${configFileName(configPath)} file should point to the file generated by the custom build.`
+			build.command,
+			configPath
 		);
 	} else {
-		assertEntryPointExists(
-			expectedEntryAbsolute,
-			expectedEntryRelative,
-			`The entry-point file at "${expectedEntryRelative}" was not found.`
-		);
+		assertEntryPointExists(expectedEntryAbsolute, expectedEntryRelative);
 	}
 }
 
@@ -81,14 +78,16 @@ export async function runCustomBuild(
 function assertEntryPointExists(
 	expectedEntryAbsolute: string,
 	expectedEntryRelative: string,
-	errorMessage: string
+	customBuildCommand?: string,
+	configPath?: string
 ) {
 	if (!fileExists(expectedEntryAbsolute)) {
 		throw new UserError(
 			getMissingEntryPointMessage(
-				errorMessage,
 				expectedEntryAbsolute,
-				expectedEntryRelative
+				expectedEntryRelative,
+				customBuildCommand,
+				configPath
 			)
 		);
 	}
@@ -101,16 +100,17 @@ function assertEntryPointExists(
  * nearby to the expected file path.
  */
 function getMissingEntryPointMessage(
-	message: string,
 	absoluteEntryPointPath: string,
-	relativeEntryPointPath: string
+	relativeEntryPointPath: string,
+	customBuildCommand?: string,
+	configPath?: string
 ): string {
 	if (
 		existsSync(absoluteEntryPointPath) &&
 		statSync(absoluteEntryPointPath).isDirectory()
 	) {
 		// The expected entry-point is a directory, so offer further guidance.
-		message += `\nThe provided entry-point path, "${relativeEntryPointPath}", points to a directory, rather than a file.\n`;
+		let message = `The provided entry-point path, "${relativeEntryPointPath}", points to a directory, rather than a file.\n`;
 
 		// Perhaps we can even guess what the correct path should be...
 		const possiblePaths: string[] = [];
@@ -137,8 +137,23 @@ function getMissingEntryPointMessage(
 				possiblePaths.map((filePath) => `main = "./${filePath}"\n`).join("") +
 				"```";
 		}
+
+		return message;
 	}
-	return message;
+
+	if (customBuildCommand) {
+		return dedent`
+			The expected output file at "${relativeEntryPointPath}" was not found after running custom build: ${customBuildCommand}.
+			The \`main\` property in your ${configFileName(configPath)} file should point to the file generated by the custom build.
+		`;
+	}
+
+	return dedent`
+		 		The entry-point file at "${relativeEntryPointPath}" was not found.
+
+		 		This might mean that your entry-point file needs to be generated (which is the general case when a framework is being used).
+		 		If that's the case please run your project's build command and try again.
+		 	`;
 }
 
 /**