feat: check for forms workaround before checking for forms

Author: orinokai

Diff for: src/build/content/prerendered.ts

@@ -18,7 +18,7 @@ import type {
   NetlifyIncrementalCacheValue,
 } from '../../shared/cache-types.cjs'
 import type { PluginContext } from '../plugin-context.js'
-import { verifyNoNetlifyForms } from '../verification.js'
+import { verifyNetlifyForms } from '../verification.js'
 
 const tracer = wrapTracer(trace.getTracer('Next runtime'))
 
@@ -172,7 +172,7 @@ export const copyPrerenderedContent = async (ctx: PluginContext): Promise<void>
 
               // Netlify Forms are not support and require a workaround
               if (value.kind === 'PAGE' || value.kind === 'APP_PAGE') {
-                verifyNoNetlifyForms(ctx, value.html)
+                verifyNetlifyForms(ctx, value.html)
               }
 
               await writeCacheEntry(key, value, lastModified, ctx)

Diff for: src/build/content/static.ts

@@ -8,7 +8,7 @@ import glob from 'fast-glob'
 
 import { encodeBlobKey } from '../../shared/blobkey.js'
 import { PluginContext } from '../plugin-context.js'
-import { verifyNoNetlifyForms } from '../verification.js'
+import { verifyNetlifyForms } from '../verification.js'
 
 const tracer = wrapTracer(trace.getTracer('Next runtime'))
 
@@ -32,7 +32,7 @@ export const copyStaticContent = async (ctx: PluginContext): Promise<void> => {
           .filter((path) => !paths.includes(`${path.slice(0, -5)}.json`))
           .map(async (path): Promise<void> => {
             const html = await readFile(join(srcDir, path), 'utf-8')
-            verifyNoNetlifyForms(ctx, html)
+            verifyNetlifyForms(ctx, html)
             await writeFile(join(destDir, await encodeBlobKey(path)), html, 'utf-8')
           }),
       )

Diff for: src/build/verification.ts

@@ -1,14 +1,16 @@
 import { existsSync } from 'node:fs'
+import { readFile } from 'node:fs/promises'
 import { join } from 'node:path'
 
+import { glob } from 'fast-glob'
 import { satisfies } from 'semver'
 
 import { ApiRouteType, getAPIRoutesConfigs } from './advanced-api-routes.js'
 import type { PluginContext } from './plugin-context.js'
 
 const SUPPORTED_NEXT_VERSIONS = '>=13.5.0'
 
-const warnings = new Set<string>()
+const verifications = new Set<string>()
 
 export function verifyPublishDir(ctx: PluginContext) {
   if (!existsSync(ctx.publishDir)) {
@@ -71,7 +73,7 @@ export function verifyPublishDir(ctx: PluginContext) {
   }
 }
 
-export async function verifyNoAdvancedAPIRoutes(ctx: PluginContext) {
+export async function verifyAdvancedAPIRoutes(ctx: PluginContext) {
   const apiRoutesConfigs = await getAPIRoutesConfigs(ctx)
 
   const unsupportedAPIRoutes = apiRoutesConfigs.filter((apiRouteConfig) => {
@@ -88,11 +90,33 @@ export async function verifyNoAdvancedAPIRoutes(ctx: PluginContext) {
   }
 }
 
-export function verifyNoNetlifyForms(ctx: PluginContext, html: string) {
-  if (!warnings.has('netlifyForms') && /<form[^>]*?\s(netlify|data-netlify)[=>\s]/.test(html)) {
+const formDetectionRegex = /<form[^>]*?\s(netlify|data-netlify)[=>\s]/
+
+export async function verifyNetlifyFormsWorkaround(ctx: PluginContext) {
+  const srcDir = ctx.resolveFromSiteDir('public')
+  const paths = await glob(join(srcDir, '**/*.html'))
+  try {
+    const hasWorkaround = await paths.some(async (path): Promise<boolean> => {
+      const html = await readFile(path, 'utf-8')
+      return formDetectionRegex.test(html)
+    })
+    if (hasWorkaround) {
+      verifications.add('netlifyFormsWorkaround')
+    }
+  } catch (error) {
+    ctx.failBuild('Failed verifying public files', error)
+  }
+}
+
+export function verifyNetlifyForms(ctx: PluginContext, html: string) {
+  if (
+    !verifications.has('netlifyForms') &&
+    !verifications.has('netlifyFormsWorkaround') &&
+    formDetectionRegex.test(html)
+  ) {
     console.warn(
       '@netlify/plugin-next@5 does not support Netlify Forms. Refer to https://ntl.fyi/next-runtime-forms-migration for migration example.',
     )
-    warnings.add('netlifyForms')
+    verifications.add('netlifyForms')
   }
 }

Diff for: src/index.ts

@@ -17,7 +17,11 @@ import { createEdgeHandlers } from './build/functions/edge.js'
 import { createServerHandler } from './build/functions/server.js'
 import { setImageConfig } from './build/image-cdn.js'
 import { PluginContext } from './build/plugin-context.js'
-import { verifyNoAdvancedAPIRoutes, verifyPublishDir } from './build/verification.js'
+import {
+  verifyAdvancedAPIRoutes,
+  verifyNetlifyFormsWorkaround,
+  verifyPublishDir,
+} from './build/verification.js'
 
 const tracer = wrapTracer(trace.getTracer('Next.js runtime'))
 
@@ -58,7 +62,8 @@ export const onBuild = async (options: NetlifyPluginOptions) => {
       return copyStaticExport(ctx)
     }
 
-    await verifyNoAdvancedAPIRoutes(ctx)
+    await verifyAdvancedAPIRoutes(ctx)
+    await verifyNetlifyFormsWorkaround(ctx)
 
     await Promise.all([
       copyStaticAssets(ctx),