fix: prevent adding default supportFile on migration (#21985)

* fix: prevent adding default supportFile on migration

* Update unit tests

Co-authored-by: Tim Griesser <tgriesser10@gmail.com>

packages/data-context/src/sources/migration/codegen.ts

@@ -435,6 +435,13 @@ export function reduceConfig (cfg: LegacyCypressConfigJson, options: CreateConfi
           component: { ...acc.component, excludeSpecPattern: val },
         }
       case 'supportFile':
+        // If the supportFile is set, but is the same value as the default one; where
+        // we migrate it, we do not want to put the legacy value in the migrated config.
+        // It can be .ts or .js
+        if (_.isNil(val) || !_.isBoolean(val) && val.match(/^cypress\/support($|\/index($|\.(ts|js)$))/)) {
+          return acc
+        }
+
         return {
           ...acc,
           e2e: { ...acc.e2e, supportFile: val },

packages/data-context/test/unit/sources/migration/codegen.spec.ts

@@ -517,12 +517,20 @@ describe('reduceConfig', () => {
   })
 
   it('should nest supportFile under component and e2e', () => {
-    const config = { supportFile: 'cypress/support/index.js' }
+    const config = { supportFile: 'cypress/support/mySupportFile.js' }
     const newConfig = reduceConfig(config, options)
 
     expect(newConfig.e2e.supportFile).to.eq(config.supportFile)
   })
 
+  it('should not add supportFile if it is the default one', () => {
+    expect(reduceConfig({ supportFile: null }, options).e2e.supportFile).to.not.exist
+    expect(reduceConfig({ supportFile: undefined }, options).e2e.supportFile).to.not.exist
+    expect(reduceConfig({ supportFile: 'cypress/support' }, options).e2e.supportFile).to.not.exist
+    expect(reduceConfig({ supportFile: 'cypress/support/index' }, options).e2e.supportFile).to.not.exist
+    expect(reduceConfig({ supportFile: 'cypress/support/index.js' }, options).e2e.supportFile).to.not.exist
+  })
+
   it('should exclude the pluginsFile', () => {
     const config = { pluginsFile: 'cypress/plugins/index.js' }
     const newConfig = reduceConfig(config, options)

packages/launchpad/cypress/e2e/migration.cy.ts

@@ -503,6 +503,41 @@ describe('Full migration flow for each project', { retries: { openMode: 0, runMo
     checkOutcome()
   })
 
+  it('completes journey for migration-e2e-custom-supportFile-default-value', () => {
+    startMigrationFor('migration-e2e-custom-supportFile-default-value')
+    // default testFiles but custom integration - can rename automatically
+    cy.get(renameAutoStep).should('exist')
+    // no CT
+    cy.get(renameManualStep).should('not.exist')
+    // supportFile is false - cannot migrate
+    cy.get(renameSupportStep).should('exist')
+    cy.get(setupComponentStep).should('not.exist')
+    cy.get(configFileStep).should('exist')
+
+    // Migration workflow
+    // before auto migration
+    cy.contains('cypress/integration/basic.spec.js')
+
+    // after auto migration
+    cy.contains('cypress/e2e/basic.cy.js')
+
+    runAutoRename()
+
+    cy.withRetryableCtx(async (ctx) => {
+      const specs = ['cypress/e2e/basic.cy.js']
+
+      for (const spec of specs) {
+        const stats = await ctx.file.checkIfFileExists(ctx.path.join(spec))
+
+        expect(stats).to.not.be.null
+      }
+    })
+
+    renameSupport()
+    migrateAndVerifyConfig()
+    checkOutcome()
+  })
+
   it('completes journey for migration-e2e-custom-integration-default-value', () => {
     startMigrationFor('migration-e2e-custom-integration-default-value')
     // default testFiles but custom integration - can rename automatically

system-tests/projects/migration-e2e-custom-supportFile-default-value/README.md

@@ -0,0 +1,40 @@
+## Migration E2E Custom SupportFile with default value
+
+An e2e project with a custom `supportFile` named `cypress/support/index.js`. It uses the default `supportFile`. We will not
+update the config file to show the supportFile because it is the same as the default one
+
+The following migration steps will be used during this migration:
+
+- [x] automatic file rename
+- [ ] manual file rename
+- [x] rename support
+- [x] update config file
+- [ ] setup component testing
+
+
+## Automatic Migration
+
+Unless the user skips this step, after this step, the filesystem will be:
+
+| Before | After|
+|---|---|
+| `src/basic.test.js` | `src/basic.cy.js` |
+
+## Manual Files
+
+This step is not used.
+
+## Rename supportFile
+
+The project has a default support file, `cypress/support/index.js`. We can rename it for them to `cypress/support/e2e.js`.
+
+| Before | After|
+|---|---|
+| `cypress/support/index.js` | `cypress/support/e2e.js` |
+
+## Update Config
+
+We can migrate to the new `cypress.config.js`. The expected output is in `expected-cypress.config.js`. The main points are:
+
+
+The expected output is in [`expected-cypress.config.js`](./expected-cypress.config.js).

system-tests/projects/migration-e2e-custom-supportFile-default-value/cypress.json

@@ -0,0 +1,3 @@
+{
+  "supportFile": "cypress/support/index.js"
+}

system-tests/projects/migration-e2e-custom-supportFile-default-value/expected-cypress.config.js

@@ -0,0 +1,11 @@
+const { defineConfig } = require('cypress')
+
+module.exports = defineConfig({
+  e2e: {
+    // We've imported your old cypress plugins here.
+    // You may want to clean this up later by importing these.
+    setupNodeEvents (on, config) {
+      return require('./cypress/plugins/index.js')(on, config)
+    },
+  },
+})