detect version channel (#66)

Author: huozhi

src/_internal/nextjs-channel-detector.ts

@@ -0,0 +1,62 @@
+import { readFileSync, existsSync } from "fs"
+import { join } from "path"
+
+export interface ChannelDetectionResult {
+  isBeta: boolean
+  isCanary: boolean
+  currentVersion: string | null
+}
+
+/**
+ * Detects the Next.js channel (beta/canary/stable) from a project's package.json
+ * @param projectPath - Path to the Next.js project directory
+ * @returns Channel detection result with isBeta, isCanary, and currentVersion
+ */
+export function detectProjectChannel(projectPath: string): ChannelDetectionResult {
+  const packageJsonPath = join(projectPath, "package.json")
+
+  if (!existsSync(packageJsonPath)) {
+    return { isBeta: false, isCanary: false, currentVersion: null }
+  }
+
+  try {
+    const packageJson = JSON.parse(readFileSync(packageJsonPath, "utf-8"))
+    const nextVersion = packageJson.dependencies?.next || packageJson.devDependencies?.next
+
+    if (!nextVersion) {
+      return { isBeta: false, isCanary: false, currentVersion: null }
+    }
+
+    const isBeta = nextVersion.includes("beta") || nextVersion.includes("16.0.0-beta")
+    const isCanary = nextVersion === "canary" || nextVersion.includes("canary")
+
+    return { isBeta, isCanary, currentVersion: nextVersion }
+  } catch (error) {
+    console.warn("Failed to parse package.json, assuming not on beta/canary")
+    return { isBeta: false, isCanary: false, currentVersion: null }
+  }
+}
+
+/**
+ * Processes conditional template blocks based on channel detection
+ * Supports {{IF_BETA_CHANNEL}} blocks
+ * @param template - Template string with conditional blocks
+ * @param isBeta - Whether the project is on beta channel
+ * @returns Processed template with conditional blocks resolved
+ */
+export function processConditionalBlocks(template: string, isBeta: boolean): string {
+  let result = template
+
+  // Process IF_BETA_CHANNEL blocks
+  if (isBeta) {
+    // Keep content, remove markers
+    result = result.replace(/\{\{IF_BETA_CHANNEL\}\}/g, "")
+    result = result.replace(/\{\{\/IF_BETA_CHANNEL\}\}/g, "")
+  } else {
+    // Remove entire block including content
+    result = result.replace(/\{\{IF_BETA_CHANNEL\}\}.*?\{\{\/IF_BETA_CHANNEL\}\}/gs, "")
+  }
+
+  return result
+}
+

src/prompts/upgrade-nextjs-16-prompt.md

@@ -328,9 +328,18 @@ After the codemod runs, check for any remaining issues it might have missed:
    File: next.config.js
    Check: `serverComponentsExternalPackages` in experimental config
    Action: Move out of experimental - this is now a top-level config option
-   
+
    **📖 For code examples, see: `nextjs16://migration/examples` (Config Migration Examples)**
 
+   {{IF_BETA_CHANNEL}}**J. Beta to Stable Migration (REQUIRED for beta channel users)**
+
+   You are currently upgrading to Next.js 16 **beta** channel. When Next.js 16 **stable** is released, you will need to apply additional config migrations:
+
+   {{BETA_TO_STABLE_GUIDE}}
+
+   **Key migration when stable is released**: `experimental.cacheLife` must be moved to top-level `cacheLife`{{/IF_BETA_CHANNEL}}
+   
+
 **K. Edge Cases the Codemod May Miss**
    Review these manually:
 
@@ -535,10 +544,6 @@ Report findings in this format:
 - [ ] Codemod upgraded Next.js, React, and React DOM to stable
 - [ ] Codemod upgraded React type definitions to stable
 - [ ] Codemod applied automatic fixes
-{{IF_REQUIRES_CANARY}}
-- [ ] (Optional) Upgraded to canary: `<pkg-manager> add next@canary`
-- [ ] (Optional) Upgraded eslint-config-next: `<pkg-manager> add -D eslint-config-next@canary`
-{{/IF_REQUIRES_CANARY}}
 - [ ] TypeScript upgraded if needed: `<pkg-manager> add -D typescript@latest`
 - [ ] Reviewed git diff for codemod changes
 - [ ] **Verified build: `<pkg-manager> run build` (if this passes, upgrade is complete!)**

src/prompts/upgrade-nextjs-16.ts

@@ -2,6 +2,10 @@ import { type InferSchema, type PromptMetadata } from "xmcp"
 import { z } from "zod"
 import { readResourceFile } from "../_internal/resource-path"
 import { execSync } from "child_process"
+import {
+  detectProjectChannel,
+  processConditionalBlocks,
+} from "../_internal/nextjs-channel-detector"
 
 export const schema = {
   project_path: z
@@ -37,12 +41,18 @@ export default function getUpgradeNextjs16Prompt(args: InferSchema<typeof schema
   const upgradeChannel = "latest"
   const codemodCommandNote = `**Note**: Next.js 16 stable (version ${version}) is now available.`
 
+  // Detect if project is on beta/canary
+  const { isBeta } = detectProjectChannel(projectPath)
+
   let promptTemplate = readResourceFile("prompts/upgrade-nextjs-16-prompt.md")
 
-  // TODO: load next.js16 knowledge base resources
+  // Replace basic template variables
   promptTemplate = promptTemplate.replace(/{{PROJECT_PATH}}/g, projectPath)
   promptTemplate = promptTemplate.replace(/{{UPGRADE_CHANNEL}}/g, upgradeChannel)
   promptTemplate = promptTemplate.replace(/{{CODEMOD_COMMAND}}/g, codemodCommandNote)
 
+  // Process conditional blocks based on project channel
+  promptTemplate = processConditionalBlocks(promptTemplate, isBeta)
+
   return promptTemplate
 }

test/prompts/prompts.test.ts

@@ -29,5 +29,18 @@ describe('Prompts Token Size', () => {
 
     expect(estimatedTokens).toBeLessThan(10000)
   })
+
+  it('upgrade-nextjs-16 should not contain unprocessed template markers', () => {
+    const result = getUpgradeNextjs16Prompt({ project_path: undefined })
+
+    // Verify all conditional blocks are processed (no leftover markers)
+    expect(result).not.toContain('{{IF_BETA_CHANNEL}}')
+    expect(result).not.toContain('{{/IF_BETA_CHANNEL}}')
+    
+    // Verify basic template variables are replaced
+    expect(result).not.toContain('{{PROJECT_PATH}}')
+    expect(result).not.toContain('{{UPGRADE_CHANNEL}}')
+    expect(result).not.toContain('{{CODEMOD_COMMAND}}')
+  })
 })