feat: support inline diff options and support printBasicPrototype

docs/config/index.md

@@ -2276,9 +2276,26 @@ export default defineConfig({
 ### diff
 
 - **Type:** `string`
-- **CLI:** `--diff=<value>`
+- **CLI:** `--diff=<path>`
 
-Path to a diff config that will be used to generate diff interface. Useful if you want to customize diff display.
+`DiffOptions` object or a path to a module which exports `DiffOptions`. Useful if you want to customize diff display.
+
+:::code-group
+```ts [vitest.config.js]
+import { defineConfig } from 'vitest/config'
+import c from 'tinyrainbow'
+
+export default defineConfig({
+  test: {
+    diff: {
+      aIndicator: c.bold('--'),
+      bIndicator: c.bold('++'),
+      omitAnnotationLines: true,
+    }
+  }
+})
+```
+:::
 
 :::code-group
 ```ts [vitest.diff.ts]
@@ -2303,10 +2320,19 @@ export default defineConfig({
 ```
 :::
 
+#### diff.expand
+
+- **Type**: `boolean`
+- **Default**: `true`
+- **CLI:** `--diff.expand=false`
+
+Expand all common lines.
+
 #### diff.truncateThreshold
 
 - **Type**: `number`
 - **Default**: `0`
+- **CLI:** `--diff.truncateThreshold=<path>`
 
 The maximum length of diff result to be displayed. Diffs above this threshold will be truncated.
 Truncation won't take effect with default value 0.
@@ -2315,6 +2341,7 @@ Truncation won't take effect with default value 0.
 
 - **Type**: `string`
 - **Default**: `'... Diff result is truncated'`
+- **CLI:** `--diff.truncateAnnotation=<annotation>`
 
 Annotation that is output at the end of diff result if it's truncated.
 

packages/browser/src/node/plugin.ts

@@ -209,7 +209,7 @@ export default (browserServer: BrowserServer, base = '/'): Plugin[] => {
           'msw/browser',
         ]
 
-        if (project.config.diff) {
+        if (typeof project.config.diff === 'string') {
           entries.push(project.config.diff)
         }
 

packages/utils/src/diff/index.ts

@@ -23,7 +23,7 @@ import { normalizeDiffOptions } from './normalizeDiffOptions'
 import { diffStringsRaw, diffStringsUnified } from './printDiffs'
 import type { DiffOptions } from './types'
 
-export type { DiffOptions, DiffOptionsColor } from './types'
+export type { DiffOptions, SerializedDiffOptions, DiffOptionsColor } from './types'
 
 export { diffLinesRaw, diffLinesUnified, diffLinesUnified2 }
 export { diffStringsRaw, diffStringsUnified }

packages/utils/src/diff/types.ts

@@ -32,6 +32,21 @@ export interface DiffOptions {
   truncateAnnotationColor?: DiffOptionsColor
 }
 
+export interface SerializedDiffOptions {
+  aAnnotation?: string
+  aIndicator?: string
+  bAnnotation?: string
+  bIndicator?: string
+  commonIndicator?: string
+  contextLines?: number
+  emptyFirstOrLastLinePlaceholder?: string
+  expand?: boolean
+  includeChangeCounts?: boolean
+  omitAnnotationLines?: boolean
+  truncateThreshold?: number
+  truncateAnnotation?: string
+}
+
 export interface DiffOptionsNormalized {
   aAnnotation: string
   aColor: DiffOptionsColor

packages/vitest/src/node/cli/cli-config.ts

@@ -598,9 +598,55 @@ export const cliOptionsConfig: VitestCLIOptions = {
   },
   diff: {
     description:
-      'Path to a diff config that will be used to generate diff interface',
+      'DiffOptions object or a path to a module which exports DiffOptions object',
     argument: '<path>',
-    normalize: true,
+    subcommands: {
+      aAnnotation: {
+        description: 'Annotation for expected lines (default: `Expected`)',
+        argument: '<annotation>',
+      },
+      aIndicator: {
+        description: 'Indicator for expected lines (default: `-`)',
+        argument: '<indicator>',
+      },
+      bAnnotation: {
+        description: 'Annotation for received lines (default: `Received`)',
+        argument: '<annotation>',
+      },
+      bIndicator: {
+        description: 'Indicator for received lines (default: `+`)',
+        argument: '<indicator>',
+      },
+      commonIndicator: {
+        description: 'Indicator for common lines (default: ` `)',
+        argument: '<indicator>',
+      },
+      contextLines: {
+        description: 'Number of lines of context to show around each change (default: `5`)',
+        argument: '<lines>',
+      },
+      emptyFirstOrLastLinePlaceholder: {
+        description: 'Placeholder for an empty first or last line (default: `""`)',
+        argument: '<placeholder>',
+      },
+      expand: {
+        description: 'Expand all common lines (default: `true`)',
+      },
+      includeChangeCounts: {
+        description: 'Include comparison counts in diff output (default: `false`)',
+      },
+      omitAnnotationLines: {
+        description: 'Omit annotation lines from the output (default: `false`)',
+      },
+      truncateThreshold: {
+        description: 'Number of lines to show before and after each change (default: `0`)',
+        argument: '<threshold>',
+      },
+      truncateAnnotation: {
+        description: 'Annotation for truncated lines (default: `... Diff result is truncated`)',
+        argument: '<annotation>',
+      },
+    },
   },
   exclude: {
     description: 'Additional file globs to be excluded from test',

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

@@ -578,7 +578,7 @@ export function resolveConfig(
     }
   }
 
-  if (resolved.diff) {
+  if (typeof resolved.diff === 'string') {
     resolved.diff = resolvePath(resolved.diff, resolved.root)
     resolved.forceRerunTriggers.push(resolved.diff)
   }

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

@@ -37,6 +37,7 @@ export function serializeConfig(
     pool: config.pool,
     expect: config.expect,
     snapshotSerializers: config.snapshotSerializers,
+    // TODO: non serializable function?
     diff: config.diff,
     retry: config.retry,
     disableConsoleIntercept: config.disableConsoleIntercept,

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

@@ -4,6 +4,7 @@ import type { FakeTimerInstallOpts } from '@sinonjs/fake-timers'
 import type { SequenceHooks, SequenceSetupFiles } from '@vitest/runner'
 import type { ViteNodeServerOptions } from 'vite-node'
 import type { SnapshotStateOptions } from '@vitest/snapshot'
+import type { SerializedDiffOptions } from '@vitest/utils/diff'
 import type {
   BuiltinReporterOptions,
   BuiltinReporters,
@@ -563,7 +564,7 @@ export interface InlineConfig {
   /**
    * Path to a module which has a default export of diff config.
    */
-  diff?: string
+  diff?: string | SerializedDiffOptions
 
   /**
    * Paths to snapshot serializer modules.
@@ -979,7 +980,7 @@ export interface ResolvedConfig
   mode: VitestRunMode
 
   base?: string
-  diff?: string
+  diff?: string | SerializedDiffOptions
   bail?: number
 
   setupFiles: string[]

packages/vitest/src/runtime/config.ts

@@ -3,6 +3,7 @@ import type { PrettyFormatOptions } from '@vitest/pretty-format'
 import type { SequenceHooks, SequenceSetupFiles } from '@vitest/runner'
 import type { SnapshotUpdateState } from '@vitest/snapshot'
 import type { SnapshotEnvironment } from '@vitest/snapshot/environment'
+import type { SerializedDiffOptions } from '@vitest/utils/diff'
 
 /**
  * Config that tests have access to.
@@ -98,7 +99,7 @@ export interface SerializedConfig {
     showDiff?: boolean
     truncateThreshold?: number
   } | undefined
-  diff: string | undefined
+  diff: string | SerializedDiffOptions | undefined
   retry: number
   includeTaskLocation: boolean | undefined
   inspect: boolean | string | undefined

packages/vitest/src/runtime/setup-common.ts

@@ -47,6 +47,9 @@ export async function loadDiffConfig(
   config: SerializedConfig,
   executor: VitestExecutor,
 ) {
+  if (typeof config.diff === 'object') {
+    return config.diff
+  }
   if (typeof config.diff !== 'string') {
     return
   }

test/config/fixtures/diff/basic.test.ts

@@ -0,0 +1,10 @@
+import { expect, test } from 'vitest'
+
+test('large diff', () => {
+  const x = [...Array(30)].map((_, i) => i);
+  const y = [...x];
+  y[0] = 1000;
+  y[15] = 2000;
+  y[29] = 3000;
+  expect(x).toEqual(y)
+})

test/config/fixtures/diff/vite.config.ts

@@ -0,0 +1,3 @@
+import {defineConfig} from 'vitest/config'
+
+export default defineConfig({})

test/config/test/__snapshots__/diff.test.ts.snap

@@ -0,0 +1,83 @@
+// Vitest Snapshot v1, https://vitest.dev/guide/snapshot.html
+
+exports[`inline diff options: { expand: false } 1`] = `
+[
+  "- Expected
++ Received
+
+@@ -1,7 +1,7 @@
+  Array [
+-   1000,
++   0,
+    1,
+    2,
+    3,
+    4,
+    5,
+@@ -12,11 +12,11 @@
+    10,
+    11,
+    12,
+    13,
+    14,
+-   2000,
++   15,
+    16,
+    17,
+    18,
+    19,
+    20,
+@@ -26,7 +26,7 @@
+    24,
+    25,
+    26,
+    27,
+    28,
+-   3000,
++   29,
+  ]",
+]
+`;
+
+exports[`inline diff options: undefined 1`] = `
+[
+  "- Expected
++ Received
+
+  Array [
+-   1000,
++   0,
+    1,
+    2,
+    3,
+    4,
+    5,
+    6,
+    7,
+    8,
+    9,
+    10,
+    11,
+    12,
+    13,
+    14,
+-   2000,
++   15,
+    16,
+    17,
+    18,
+    19,
+    20,
+    21,
+    22,
+    23,
+    24,
+    25,
+    26,
+    27,
+    28,
+-   3000,
++   29,
+  ]",
+]
+`;

test/config/test/diff.test.ts

@@ -0,0 +1,21 @@
+import { stripVTControlCharacters } from 'node:util'
+import { expect, test } from 'vitest'
+import { runVitest } from '../../test-utils'
+
+test.for([
+  [undefined],
+  [{ expand: false }],
+])(`inline diff options: %o`, async ([options]) => {
+  const { ctx } = await runVitest({
+    root: './fixtures/diff',
+    diff: options,
+  })
+  const errors = ctx!.state
+    .getFiles()
+    .flatMap(f =>
+      f.tasks.flatMap(t => t.result?.errors ?? []),
+    )
+  expect(
+    errors.map(e => e.diff && stripVTControlCharacters(e.diff)),
+  ).matchSnapshot()
+})