Require generated aliases to meet stricter naming requirements (#9821)

Test alias names with a regex to ensure it meets requirements prior
to version upload. When we enable this for WCI we want to ensure that
we aren't failing builds because the name is invalid.

Author: WillTaylorDev

.changeset/heavy-wasps-switch.md

@@ -0,0 +1,7 @@
+---
+"wrangler": patch
+---
+
+Preview Aliases: Force alias generation to meet stricter naming requirements.
+
+For cases where CI is requesting Wrangler to generate the alias based on the branch name, we want a stricter check around the generated alias name in order to avoid version upload failures. If a valid alias name was not able to be generated, we warn and do not provide an alias (avoiding a version upload failure).

packages/wrangler/src/__tests__/versions/versions.upload.test.ts

@@ -420,4 +420,25 @@ describe("generatePreviewAlias", () => {
 		const result = generatePreviewAlias("testscript");
 		expect(result).toBeUndefined();
 	});
+
+	it("Strips leading dashes from branch name", () => {
+		vi.stubEnv("WORKERS_CI_BRANCH", "-some-branch-name");
+
+		const result = generatePreviewAlias("testscript");
+		expect(result).toBe("some-branch-name");
+	});
+
+	it("Removes concurrent dashes from branch name", () => {
+		vi.stubEnv("WORKERS_CI_BRANCH", "some----branch-----name");
+
+		const result = generatePreviewAlias("testscript");
+		expect(result).toBe("some-branch-name");
+	});
+
+	it("Does not produce an alias with leading numbers", () => {
+		vi.stubEnv("WORKERS_CI_BRANCH", "0AF0ED");
+
+		const result = generatePreviewAlias("testscript");
+		expect(result).toBeUndefined();
+	});
 });

packages/wrangler/src/versions/upload.ts

@@ -902,6 +902,13 @@ function formatTime(duration: number) {
  * Returns undefined if not in a git directory or requirements cannot be met.
  */
 export function generatePreviewAlias(scriptName: string): string | undefined {
+	const warnAndExit = () => {
+		logger.warn(
+			`Preview alias generation requested, but could not be autogenerated.`
+		);
+		return undefined;
+	};
+
 	let branchName = getWorkersCIBranchName();
 	if (!branchName) {
 		try {
@@ -910,18 +917,12 @@ export function generatePreviewAlias(scriptName: string): string | undefined {
 				.toString()
 				.trim();
 		} catch (err) {
-			logger.warn(
-				`Preview alias generation requested, but could not be autogenerated.`
-			);
-			return undefined;
+			return warnAndExit();
 		}
 	}
 
 	if (!branchName) {
-		logger.warn(
-			`Preview alias generation requested, but could not be autogenerated.`
-		);
-		return undefined;
+		return warnAndExit();
 	}
 
 	const sanitizedAlias = branchName
@@ -930,15 +931,24 @@ export function generatePreviewAlias(scriptName: string): string | undefined {
 		.replace(/^-+|-+$/g, "") // trim dashes
 		.toLowerCase(); // lowercase the name
 
+	// Ensure the alias name meets requirements:
+	// - only alphanumeric or hyphen characters
+	// - no trailing slashes
+	// - begins with letter
+	// - no longer than 63 total characters
+	const isValidAlias = /^[a-z](?:[a-z0-9-]{0,61}[a-z0-9])?$/.test(
+		sanitizedAlias
+	);
+	if (!isValidAlias) {
+		return warnAndExit();
+	}
+
 	// Dns labels can only have a max of 63 chars. We use preview urls in the form of <alias>-<workerName>
 	// which means our alias must be shorter than 63-scriptNameLen-1
 	const maxDnsLabelLength = 63;
 	const available = maxDnsLabelLength - scriptName.length - 1;
 	if (sanitizedAlias.length > available) {
-		logger.warn(
-			`Preview alias generation requested, but could not be autogenerated.`
-		);
-		return undefined;
+		return warnAndExit();
 	}
 
 	return sanitizedAlias;