fix(code-schematics): preserve project-specific gitignore entries

code/code-schematics/src/schematic/project/project.factory.ts

@@ -1,4 +1,6 @@
 import type { Rule }                     from '@angular-devkit/schematics'
+import type { SchematicContext }         from '@angular-devkit/schematics'
+import type { Tree }                     from '@angular-devkit/schematics'
 
 import { MergeStrategy }                 from '@angular-devkit/schematics'
 import { chain }                         from '@angular-devkit/schematics'
@@ -7,10 +9,57 @@ import { mergeWith }                     from '@angular-devkit/schematics'
 import { updateTsConfigRule }            from '../rules/index.js'
 import { generateCommonSource }          from '../sources/index.js'
 import { generateProjectSpecificSource } from '../sources/index.js'
+import { mergeGitIgnoreContent }         from '../utils/index.js'
 
-export const main = (options: Record<string, string>): Rule =>
-  chain([
+const GITIGNORE_PATH = '.gitignore'
+
+const captureGitIgnoreContentRule = (state: { content?: string }): Rule =>
+  (host: Tree): Tree => {
+    const gitIgnoreBuffer = host.read(GITIGNORE_PATH)
+
+    if (!gitIgnoreBuffer) {
+      return host
+    }
+
+    state.content = gitIgnoreBuffer.toString('utf-8')
+
+    return host
+  }
+
+const mergeGitIgnoreContentRule = (state: { content?: string }): Rule =>
+  (host: Tree, context: SchematicContext): Tree => {
+    if (state.content === undefined) {
+      return host
+    }
+
+    const gitIgnoreBuffer = host.read(GITIGNORE_PATH)
+
+    if (!gitIgnoreBuffer) {
+      return host
+    }
+
+    const templateContent = gitIgnoreBuffer.toString('utf-8')
+    const mergedContent = mergeGitIgnoreContent({
+      existingContent: state.content,
+      templateContent,
+    })
+
+    if (mergedContent !== templateContent) {
+      context.logger.info('Merging template .gitignore with project-specific entries')
+      host.overwrite(GITIGNORE_PATH, mergedContent)
+    }
+
+    return host
+  }
+
+export const main = (options: Record<string, string>): Rule => {
+  const state: { content?: string } = {}
+
+  return chain([
+    captureGitIgnoreContentRule(state),
     updateTsConfigRule,
     mergeWith(generateCommonSource(options), MergeStrategy.Overwrite),
     mergeWith(generateProjectSpecificSource(options), MergeStrategy.Overwrite),
+    mergeGitIgnoreContentRule(state),
   ])
+}

code/code-schematics/src/schematic/utils/index.ts

@@ -1,4 +1,5 @@
 export * from './gitignore.utils.js'
+export * from './merge-gitignore-content.utils.js'
 export * from './tsconfig.utils.js'
 export * from './json.utils.js'
 export * from './yaml.utils.js'

code/code-schematics/src/schematic/utils/merge-gitignore-content.utils.test.ts

@@ -0,0 +1,228 @@
+import assert                    from 'node:assert/strict'
+import { test }                  from 'node:test'
+
+import { mergeGitIgnoreContent } from './merge-gitignore-content.utils.js'
+
+test('should preserve project-specific entries while keeping template section deterministic', () => {
+  const templateContent = ['node_modules', '.yarn/install-state.gz', 'dist/'].join('\n')
+  const existingContent = ['node_modules', '.idea/', '.yarn/install-state.gz', 'coverage/'].join(
+    '\n'
+  )
+
+  const actual = mergeGitIgnoreContent({
+    existingContent,
+    templateContent,
+  })
+
+  assert.equal(
+    actual,
+    [
+      'node_modules',
+      '.yarn/install-state.gz',
+      'dist/',
+      '',
+      '# raijin:begin project-specific gitignore',
+      '.idea/',
+      'coverage/',
+      '# raijin:end project-specific gitignore',
+    ].join('\n')
+  )
+})
+
+test('should be idempotent for already merged gitignore content', () => {
+  const templateContent = ['node_modules', '.yarn/install-state.gz', 'dist/'].join('\n')
+  const mergedContent = [
+    'node_modules',
+    '.yarn/install-state.gz',
+    'dist/',
+    '',
+    '# raijin:begin project-specific gitignore',
+    '.idea/',
+    '# raijin:end project-specific gitignore',
+  ].join('\n')
+
+  const actual = mergeGitIgnoreContent({
+    existingContent: mergedContent,
+    templateContent,
+  })
+
+  assert.equal(actual, mergedContent)
+})
+
+test('should not duplicate template entries from project content', () => {
+  const templateContent = ['node_modules', '.yarn/install-state.gz', 'dist/'].join('\n')
+  const existingContent = ['node_modules', '.yarn/install-state.gz', 'dist/'].join('\n')
+
+  const actual = mergeGitIgnoreContent({
+    existingContent,
+    templateContent,
+  })
+
+  assert.equal(actual, templateContent)
+})
+
+test('should not create project-specific block for blank existing content', () => {
+  const templateContent = ['node_modules', '.yarn/install-state.gz', 'dist/'].join('\n')
+
+  const actual = mergeGitIgnoreContent({
+    existingContent: '\n',
+    templateContent,
+  })
+
+  assert.equal(actual, templateContent)
+})
+
+test('should not keep removed template rules when managed block exists', () => {
+  const templateContent = ['node_modules', '.yarn/install-state.gz'].join('\n')
+  const existingContent = [
+    'node_modules',
+    '.yarn/install-state.gz',
+    'dist/',
+    '',
+    '# raijin:begin project-specific gitignore',
+    '.idea/',
+    '# raijin:end project-specific gitignore',
+  ].join('\n')
+
+  const actual = mergeGitIgnoreContent({
+    existingContent,
+    templateContent,
+  })
+
+  assert.equal(
+    actual,
+    [
+      'node_modules',
+      '.yarn/install-state.gz',
+      '',
+      '# raijin:begin project-specific gitignore',
+      'dist/',
+      '.idea/',
+      '# raijin:end project-specific gitignore',
+    ].join('\n')
+  )
+})
+
+test('should normalize CRLF input before comparison', () => {
+  const templateContent = ['node_modules', '.yarn/install-state.gz', 'dist/'].join('\n')
+  const existingContent = ['node_modules', '.yarn/install-state.gz', 'dist/', '.idea/'].join('\r\n')
+
+  const actual = mergeGitIgnoreContent({
+    existingContent,
+    templateContent,
+  })
+
+  assert.equal(
+    actual,
+    [
+      'node_modules',
+      '.yarn/install-state.gz',
+      'dist/',
+      '',
+      '# raijin:begin project-specific gitignore',
+      '.idea/',
+      '# raijin:end project-specific gitignore',
+    ].join('\n')
+  )
+})
+
+test('should preserve project-specific lines added outside managed block', () => {
+  const templateContent = ['node_modules', '.yarn/install-state.gz', 'dist/'].join('\n')
+  const existingContent = [
+    'node_modules',
+    '.yarn/install-state.gz',
+    'dist/',
+    '',
+    '.custom-above-block/',
+    '# raijin:begin project-specific gitignore',
+    '.idea/',
+    '# raijin:end project-specific gitignore',
+    '.custom-below-block/',
+  ].join('\n')
+
+  const actual = mergeGitIgnoreContent({
+    existingContent,
+    templateContent,
+  })
+
+  assert.equal(
+    actual,
+    [
+      'node_modules',
+      '.yarn/install-state.gz',
+      'dist/',
+      '',
+      '# raijin:begin project-specific gitignore',
+      '.custom-above-block/',
+      '.idea/',
+      '.custom-below-block/',
+      '# raijin:end project-specific gitignore',
+    ].join('\n')
+  )
+})
+
+test('should preserve project-specific lines in template area before managed block', () => {
+  const templateContent = ['node_modules', '.yarn/install-state.gz', 'dist/'].join('\n')
+  const existingContent = [
+    '.custom-top-line/',
+    'node_modules',
+    '.yarn/install-state.gz',
+    'dist/',
+    '',
+    '# raijin:begin project-specific gitignore',
+    '.idea/',
+    '# raijin:end project-specific gitignore',
+  ].join('\n')
+
+  const actual = mergeGitIgnoreContent({
+    existingContent,
+    templateContent,
+  })
+
+  assert.equal(
+    actual,
+    [
+      'node_modules',
+      '.yarn/install-state.gz',
+      'dist/',
+      '',
+      '# raijin:begin project-specific gitignore',
+      '.custom-top-line/',
+      '.idea/',
+      '# raijin:end project-specific gitignore',
+    ].join('\n')
+  )
+})
+
+test('should preserve project-specific negation order around managed block', () => {
+  const templateContent = ['node_modules', '.yarn/install-state.gz', 'dist/'].join('\n')
+  const existingContent = [
+    'node_modules',
+    '.yarn/install-state.gz',
+    'dist/',
+    '',
+    '*.log',
+    '# raijin:begin project-specific gitignore',
+    '!important.log',
+    '# raijin:end project-specific gitignore',
+  ].join('\n')
+
+  const actual = mergeGitIgnoreContent({
+    existingContent,
+    templateContent,
+  })
+
+  assert.equal(
+    actual,
+    [
+      'node_modules',
+      '.yarn/install-state.gz',
+      'dist/',
+      '',
+      '# raijin:begin project-specific gitignore',
+      '*.log',
+      '!important.log',
+      '# raijin:end project-specific gitignore',
+    ].join('\n')
+  )
+})

code/code-schematics/src/schematic/utils/merge-gitignore-content.utils.ts

@@ -0,0 +1,72 @@
+type MergeGitIgnoreContentOptions = {
+  existingContent: string
+  templateContent: string
+}
+
+const PROJECT_SPECIFIC_START_MARKER = '# raijin:begin project-specific gitignore'
+const PROJECT_SPECIFIC_END_MARKER = '# raijin:end project-specific gitignore'
+
+const normalizeContent = (content: string): string => content.replace(/\r\n/g, '\n')
+
+const getNormalizedLines = (content: string): Array<string> => normalizeContent(content).split('\n')
+
+const trimTrailingEmptyLines = (lines: Array<string>): Array<string> => {
+  const normalizedLines = [...lines]
+
+  while (normalizedLines.length > 0 && normalizedLines[normalizedLines.length - 1] === '') {
+    normalizedLines.pop()
+  }
+
+  return normalizedLines
+}
+
+const isProjectSpecificLine = (line: string, templateLineSet: Set<string>): boolean =>
+  line !== '' &&
+  !templateLineSet.has(line) &&
+  line !== PROJECT_SPECIFIC_START_MARKER &&
+  line !== PROJECT_SPECIFIC_END_MARKER
+
+const getProjectSpecificLines = (
+  existingLines: Array<string>,
+  templateLineSet: Set<string>
+): Array<string> => {
+  const startIndex = existingLines.indexOf(PROJECT_SPECIFIC_START_MARKER)
+  const endIndex = existingLines.indexOf(PROJECT_SPECIFIC_END_MARKER)
+
+  if (startIndex !== -1 && endIndex > startIndex) {
+    return Array.from(
+      new Set(
+        existingLines.filter((line) => isProjectSpecificLine(line, templateLineSet))
+      )
+    )
+  }
+
+  return existingLines.filter((line) => isProjectSpecificLine(line, templateLineSet))
+}
+
+export const mergeGitIgnoreContent = ({
+  existingContent,
+  templateContent,
+}: MergeGitIgnoreContentOptions): string => {
+  const templateLines = getNormalizedLines(templateContent)
+  const templateLineSet = new Set(templateLines)
+  const existingLines = getNormalizedLines(existingContent)
+
+  const projectSpecificLines = getProjectSpecificLines(existingLines, templateLineSet)
+
+  if (projectSpecificLines.length === 0) {
+    return trimTrailingEmptyLines(templateLines).join('\n')
+  }
+
+  const mergedLines = trimTrailingEmptyLines(templateLines)
+
+  if (mergedLines.length > 0) {
+    mergedLines.push('')
+  }
+
+  mergedLines.push(PROJECT_SPECIFIC_START_MARKER)
+  mergedLines.push(...projectSpecificLines)
+  mergedLines.push(PROJECT_SPECIFIC_END_MARKER)
+
+  return mergedLines.join('\n')
+}