Add strict mode for the wrangler deploy command

.changeset/calm-camels-return.md

@@ -0,0 +1,7 @@
+---
+"wrangler": minor
+---
+
+Add strict mode for the `wrangler deploy` command
+
+Add a new flag: `--strict` that makes the `wrangler deploy` command be more strict/prudent and not deploy workers when such deployments can be potentially problematic. This "strict mode" currently only affects non-interactive sessions where conflicts with the remote settings for the worker (for example when the worker has been re-deployed via the dashboard) will cause the deployment to fail instead of automatically overriding the remote settings.

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

@@ -14021,6 +14021,99 @@ export default{
 			return normalizedLog;
 		}
 	});
+
+	describe("with strict mode enabled", () => {
+		it("should error if there are remote config difference (with --x-remote-diff-check) in non-interactive mode", async () => {
+			setIsTTY(false);
+
+			writeWorkerSource();
+			mockGetServiceByName("test-name", "production", "dash");
+			writeWranglerConfig(
+				{
+					compatibility_date: "2024-04-24",
+					main: "./index.js",
+				},
+				"./wrangler.json"
+			);
+			mockSubDomainRequest();
+			mockUploadWorkerRequest();
+			mockGetServiceBindings("test-name", []);
+			mockGetServiceRoutes("test-name", []);
+			mockGetServiceCustomDomainRecords([]);
+			mockGetServiceSubDomainData("test-name", {
+				enabled: true,
+				previews_enabled: false,
+			});
+			mockGetServiceSchedules("test-name", { schedules: [] });
+			mockGetServiceMetadata("test-name", {
+				created_on: "2025-08-07T09:34:47.846308Z",
+				modified_on: "2025-08-08T10:48:12.688997Z",
+				script: {
+					created_on: "2025-08-07T09:34:47.846308Z",
+					modified_on: "2025-08-08T10:48:12.688997Z",
+					id: "silent-firefly-dbe3",
+					observability: { enabled: true, head_sampling_rate: 1 },
+					compatibility_date: "2024-04-24",
+				},
+			} as unknown as ServiceMetadataRes["default_environment"]);
+
+			await runWrangler("deploy --x-remote-diff-check --strict");
+
+			expect(std.warn).toMatchInlineSnapshot(`
+				"▲ [WARNING] The local configuration being used (generated from your local configuration file) differs from the remote configuration of your Worker set via the Cloudflare Dashboard:
+
+				        \\"bindings\\": []
+				      },
+				      \\"observability\\": {
+				  -     \\"enabled\\": true,
+				  +     \\"enabled\\": false,
+				        \\"head_sampling_rate\\": 1,
+				        \\"logs\\": {
+				          \\"enabled\\": false,
+
+				  Deploying the Worker will override the remote configuration with your local one.
+
+				"
+			`);
+
+			expect(std.err).toMatchInlineSnapshot(`
+				"X [ERROR] Aborting the deployment operation (due to strict mode, to prevent this failure either remove the \`--strict\` flag)
+
+				"
+			`);
+			// note: the test and the wrangler run share the same process, and we expect the deploy command (which fails)
+			//       to set a non-zero exit code
+			expect(process.exitCode).not.toBe(0);
+		});
+
+		it("should error when worker was last deployed from api", async () => {
+			setIsTTY(false);
+
+			msw.use(...mswSuccessDeploymentScriptAPI);
+			writeWranglerConfig();
+			writeWorkerSource();
+			mockSubDomainRequest();
+			mockUploadWorkerRequest();
+
+			await runWrangler("deploy ./index --strict");
+
+			expect(std.warn).toMatchInlineSnapshot(`
+			"▲ [WARNING] You are about to publish a Workers Service that was last updated via the script API.
+
+			  Edits that have been made via the script API will be overridden by your local code and config.
+
+			"
+			`);
+			expect(std.err).toMatchInlineSnapshot(`
+				"X [ERROR] Aborting the deployment operation (due to strict mode, to prevent this failure either remove the \`--strict\` flag)
+
+				"
+			`);
+			// note: the test and the wrangler run share the same process, and we expect the deploy command (which fails)
+			//       to set a non-zero exit code
+			expect(process.exitCode).not.toBe(0);
+		});
+	});
 });
 
 /** Write mock assets to the file system so they can be uploaded. */

packages/wrangler/src/deploy/deploy.ts

@@ -33,6 +33,7 @@ import {
 } from "../environments";
 import { UserError } from "../errors";
 import { getFlag } from "../experimental-flags";
+import { isNonInteractiveOrCI } from "../is-interactive";
 import { logger } from "../logger";
 import { getMetricsUsageHeaders } from "../metrics";
 import { isNavigatorDefined } from "../navigator-user-agent";
@@ -120,6 +121,7 @@ type Props = {
 	experimentalAutoCreate: boolean;
 	metafile: string | boolean | undefined;
 	containersRollout: "immediate" | "gradual" | undefined;
+	strict: boolean | undefined;
 };
 
 export type RouteObject = ZoneIdRoute | ZoneNameRoute | CustomDomainRoute;
@@ -357,6 +359,8 @@ export default async function deploy(props: Props): Promise<{
 	workerTag: string | null;
 	targets?: string[];
 }> {
+	const deployConfirm = getDeployConfirmFunction(props.strict);
+
 	// TODO: warn if git/hg has uncommitted changes
 	const { config, accountId, name, entry } = props;
 	let workerTag: string | null = null;
@@ -417,23 +421,23 @@ export default async function deploy(props: Props): Promise<{
 								`\n${configDiff.diff}\n\n` +
 								"Deploying the Worker will override the remote configuration with your local one."
 						);
-						if (!(await confirm("Would you like to continue?"))) {
+						if (!(await deployConfirm("Would you like to continue?"))) {
 							return { versionId, workerTag };
 						}
 					}
 				} else {
 					logger.warn(
 						`You are about to publish a Workers Service that was last published via the Cloudflare Dashboard.\nEdits that have been made via the dashboard will be overridden by your local code and config.`
 					);
-					if (!(await confirm("Would you like to continue?"))) {
+					if (!(await deployConfirm("Would you like to continue?"))) {
 						return { versionId, workerTag };
 					}
 				}
 			} else if (script.last_deployed_from === "api") {
 				logger.warn(
 					`You are about to publish a Workers Service that was last updated via the script API.\nEdits that have been made via the script API will be overridden by your local code and config.`
 				);
-				if (!(await confirm("Would you like to continue?"))) {
+				if (!(await deployConfirm("Would you like to continue?"))) {
 					return { versionId, workerTag };
 				}
 			}
@@ -1430,3 +1434,21 @@ export async function updateQueueConsumers(
 
 	return updateConsumers;
 }
+
+function getDeployConfirmFunction(
+	strictMode = false
+): (text: string) => Promise<boolean> {
+	const nonInteractive = isNonInteractiveOrCI();
+
+	if (nonInteractive && strictMode) {
+		return async () => {
+			logger.error(
+				"Aborting the deployment operation (due to strict mode, to prevent this failure either remove the `--strict` flag)"
+			);
+			process.exitCode = 1;
+			return false;
+		};
+	}
+
+	return confirm;
+}

packages/wrangler/src/deploy/index.ts

@@ -232,11 +232,17 @@ export const deployCommand = createCommand({
 			choices: ["immediate", "gradual"] as const,
 		},
 		"experimental-deploy-remote-diff-check": {
-			describe: `Experimental: Enable The Deployment Remote Diff check`,
+			describe: "Experimental: Enable The Deployment Remote Diff check",
 			type: "boolean",
 			hidden: true,
 			alias: ["x-remote-diff-check"],
 		},
+		strict: {
+			describe:
+				"Enables strict mode for the deploy command, this prevents deployments to occur when there are even small potential risks.",
+			type: "boolean",
+			default: false,
+		},
 	},
 	behaviour: {
 		useConfigRedirectIfAvailable: true,
@@ -251,7 +257,7 @@ export const deployCommand = createCommand({
 	validateArgs(args) {
 		if (args.nodeCompat) {
 			throw new UserError(
-				`The --node-compat flag is no longer supported as of Wrangler v4. Instead, use the \`nodejs_compat\` compatibility flag. This includes the functionality from legacy \`node_compat\` polyfills and natively implemented Node.js APIs. See https://developers.cloudflare.com/workers/runtime-apis/nodejs for more information.`,
+				"The --node-compat flag is no longer supported as of Wrangler v4. Instead, use the `nodejs_compat` compatibility flag. This includes the functionality from legacy `node_compat` polyfills and natively implemented Node.js APIs. See https://developers.cloudflare.com/workers/runtime-apis/nodejs for more information.",
 				{ telemetryMessage: true }
 			);
 		}
@@ -382,6 +388,7 @@ export const deployCommand = createCommand({
 			dispatchNamespace: args.dispatchNamespace,
 			experimentalAutoCreate: args.experimentalAutoCreate,
 			containersRollout: args.containersRollout,
+			strict: args.strict,
 		});
 
 		writeOutput({