fix(browser): don't fail when running --browser.headless if the browser projest is part of the workspace

packages/vitest/src/node/config/resolveConfig.ts

@@ -235,20 +235,24 @@ export function resolveConfig(
 
   if (browser.enabled) {
     if (!browser.name && !browser.instances) {
-      throw new Error(`Vitest Browser Mode requires "browser.name" (deprecated) or "browser.instances" options, none were set.`)
-    }
-
-    const configs = browser.instances
-    if (browser.name && browser.instances) {
-      // --browser=chromium filters configs to a single one
-      browser.instances = browser.instances.filter(instance => instance.browser === browser.name)
+      // CLI can enable `--browser.*` flag to change config of workspace projects
+      // the same flag will be applied to the root config that doesn't have to have "name" or "instances"
+      // in this case we just disable the browser mode
+      browser.enabled = false
     }
+    else {
+      const instances = browser.instances
+      if (browser.name && browser.instances) {
+        // --browser=chromium filters configs to a single one
+        browser.instances = browser.instances.filter(instance => instance.browser === browser.name)
+      }
 
-    if (browser.instances && !browser.instances.length) {
-      throw new Error([
-        `"browser.instances" was set in the config, but the array is empty. Define at least one browser config.`,
-        browser.name && configs?.length ? ` The "browser.name" was set to "${browser.name}" which filtered all configs (${configs.map(c => c.browser).join(', ')}). Did you mean to use another name?` : '',
-      ].join(''))
+      if (browser.instances && !browser.instances.length) {
+        throw new Error([
+          `"browser.instances" was set in the config, but the array is empty. Define at least one browser config.`,
+          browser.name && instances?.length ? ` The "browser.name" was set to "${browser.name}" which filtered all configs (${instances.map(c => c.browser).join(', ')}). Did you mean to use another name?` : '',
+        ].join(''))
+      }
     }
   }
 

test/config/test/browser-configs.test.ts

@@ -197,3 +197,45 @@ test('coverage provider v8 works correctly in browser mode if instances are filt
     'chromium',
   ])
 })
+
+test('can enable browser-cli options for multi-project workspace', async () => {
+  const { projects } = await vitest(
+    {
+      browser: {
+        enabled: true,
+        headless: true,
+      },
+    },
+    {
+      workspace: [
+        {
+          test: {
+            name: 'unit',
+          },
+        },
+        {
+          test: {
+            browser: {
+              enabled: true,
+              provider: 'playwright',
+              instances: [
+                { browser: 'chromium', name: 'browser' },
+              ],
+            },
+          },
+        },
+      ],
+    },
+  )
+  expect(projects.map(p => p.name)).toEqual([
+    'unit',
+    'browser',
+  ])
+
+  // unit config
+  expect(projects[0].config.browser.enabled).toBe(false)
+
+  // browser config
+  expect(projects[1].config.browser.enabled).toBe(true)
+  expect(projects[1].config.browser.headless).toBe(true)
+})

test/config/test/failures.test.ts

@@ -411,12 +411,6 @@ test('maxConcurrency 0 prints a warning', async () => {
   expect(stderr).toMatch('The option "maxConcurrency" cannot be set to 0. Using default value 5 instead.')
 })
 
-test('browser.name or browser.instances are required', async () => {
-  const { stderr, exitCode } = await runVitestCli('--browser.enabled')
-  expect(exitCode).toBe(1)
-  expect(stderr).toMatch('Vitest Browser Mode requires "browser.name" (deprecated) or "browser.instances" options, none were set.')
-})
-
 test('browser.instances is empty', async () => {
   const { stderr } = await runVitest({
     browser: {