Create IDE diff modules

This module parses the IDE state, and creates a diff object that can
be sent to the runner.

This module parses a single IDE file into a patch.

ee/app/assets/javascripts/ide/lib/create_diff.js

+import { commitActionForFile } from '~/ide/stores/utils';
+import { commitActionTypes } from '~/ide/constants';
+import createFileDiff from './create_file_diff';
+
+const filesWithChanges = ({ stagedFiles = [], changedFiles = [] }) => {
+  // We need changed files to overwrite staged, so put them at the end.
+  const changes = stagedFiles.concat(changedFiles).reduce((acc, file) => {
+    const key = file.path;
+    const action = commitActionForFile(file);
+    const prev = acc[key];
+
+    // If a file was deleted, which was previously added, then we should do nothing.
+    if (action === commitActionTypes.delete && prev && prev.action === commitActionTypes.create) {
+      delete acc[key];
+    } else {
+      acc[key] = { action, file };
+    }
+
+    return acc;
+  }, {});
+
+  // We need to clean "move" actions, because we can only support 100% similarity moves at the moment.
+  // This is because the previous file's content might not be loaded.
+  Object.values(changes)
+    .filter(change => change.action === commitActionTypes.move)
+    .forEach(change => {
+      const prev = changes[change.file.prevPath];
+
+      if (!prev) {
+        return;
+      }
+
+      if (change.file.content === prev.file.content) {
+        // If content is the same, continue with the move but don't do the prevPath's delete.
+        delete changes[change.file.prevPath];
+      } else {
+        // Otherwise, treat the move as a delete / create.
+        Object.assign(change, { action: commitActionTypes.create });
+      }
+    });
+
+  return Object.values(changes);
+};
+
+const createDiff = state => {
+  const changes = filesWithChanges(state);
+
+  const toDelete = changes.filter(x => x.action === commitActionTypes.delete).map(x => x.file.path);
+
+  const patch = changes
+    .filter(x => x.action !== commitActionTypes.delete)
+    .map(({ file, action }) => createFileDiff(file, action))
+    .join('');
+
+  return {
+    patch,
+    toDelete,
+  };
+};
+
+export default createDiff;

ee/app/assets/javascripts/ide/lib/create_file_diff.js

+import { createTwoFilesPatch } from 'diff';
+import { commitActionTypes } from '~/ide/constants';
+
+const DEV_NULL = '/dev/null';
+const DEFAULT_MODE = '100644';
+const NO_NEW_LINE = '\\ No newline at end of file';
+const NEW_LINE = '\n';
+
+/**
+ * Cleans patch generated by `diff` package.
+ *
+ * - Removes "=======" separator added at the beginning
+ */
+const cleanTwoFilesPatch = text => text.replace(/^(=+\s*)/, '');
+
+const endsWithNewLine = val => !val || val[val.length - 1] === NEW_LINE;
+
+const addEndingNewLine = val => (endsWithNewLine(val) ? val : val + NEW_LINE);
+
+const removeEndingNewLine = val => (endsWithNewLine(val) ? val.substr(0, val.length - 1) : val);
+
+const diffHead = (prevPath, newPath = '') =>
+  `diff --git "a/${prevPath}" "b/${newPath || prevPath}"`;
+
+const createDiffBody = (path, content, isCreate) => {
+  if (!content) {
+    return '';
+  }
+
+  const prefix = isCreate ? '+' : '-';
+  const fromPath = isCreate ? DEV_NULL : `a/${path}`;
+  const toPath = isCreate ? `b/${path}` : DEV_NULL;
+
+  const hasNewLine = endsWithNewLine(content);
+  const lines = removeEndingNewLine(content).split(NEW_LINE);
+
+  const chunkHead = isCreate ? `@@ -0,0 +1,${lines.length} @@` : `@@ -1,${lines.length} +0,0 @@`;
+  const chunk = lines
+    .map(line => `${prefix}${line}`)
+    .concat(!hasNewLine ? [NO_NEW_LINE] : [])
+    .join(NEW_LINE);
+
+  return `--- ${fromPath}
++++ ${toPath}
+${chunkHead}
+${chunk}`;
+};
+
+const createMoveFileDiff = (prevPath, newPath) => `${diffHead(prevPath, newPath)}
+rename from ${prevPath}
+rename to ${newPath}`;
+
+const createNewFileDiff = (path, content) => {
+  const diff = createDiffBody(path, content, true);
+
+  return `${diffHead(path)}
+new file mode ${DEFAULT_MODE}
+${diff}`;
+};
+
+const createDeleteFileDiff = (path, content) => {
+  const diff = createDiffBody(path, content, false);
+
+  return `${diffHead(path)}
+deleted file mode ${DEFAULT_MODE}
+${diff}`;
+};
+
+const createUpdateFileDiff = (path, oldContent, newContent) => {
+  const patch = createTwoFilesPatch(`a/${path}`, `b/${path}`, oldContent, newContent);
+
+  return `${diffHead(path)}
+${cleanTwoFilesPatch(patch)}`;
+};
+
+const createFileDiffRaw = (file, action) => {
+  switch (action) {
+    case commitActionTypes.move:
+      return createMoveFileDiff(file.prevPath, file.path);
+    case commitActionTypes.create:
+      return createNewFileDiff(file.path, file.content);
+    case commitActionTypes.delete:
+      return createDeleteFileDiff(file.path, file.content);
+    case commitActionTypes.update:
+      return createUpdateFileDiff(file.path, file.raw || '', file.content);
+    default:
+      return '';
+  }
+};
+
+/**
+ * Create a git diff for a single IDE file.
+ *
+ * ## Notes:
+ * When called with `commitActionType.move`, it assumes that the move
+ * is a 100% similarity move. No diff will be generated. This is because
+ * generating a move with changes is not support by the current IDE, since
+ * the source file might not have it's content loaded yet.
+ *
+ * When called with `commitActionType.delete`, it does not support
+ * deleting files with a mode different than 100644. For the IDE mirror, this
+ * isn't needed because deleting is handled outside the unified patch.
+ *
+ * ## References:
+ * - https://git-scm.com/docs/git-diff#_generating_patches_with_p
+ */
+const createFileDiff = (file, action) =>
+  // It's important that the file diff ends in a new line - git expects this.
+  addEndingNewLine(createFileDiffRaw(file, action));
+
+export default createFileDiff;

ee/spec/frontend/ide/file_helpers.js

+export const createFile = (path, content = '') => ({
+  id: path,
+  path,
+  content,
+  raw: content,
+});
+
+export const createNewFile = (path, content) =>
+  Object.assign(createFile(path, content), {
+    tempFile: true,
+    raw: '',
+  });
+
+export const createDeletedFile = (path, content) =>
+  Object.assign(createFile(path, content), {
+    deleted: true,
+  });
+
+export const createUpdatedFile = (path, oldContent, content) =>
+  Object.assign(createFile(path, content), {
+    raw: oldContent,
+  });
+
+export const createMovedFile = (path, prevPath, content) =>
+  Object.assign(createNewFile(path, content), {
+    prevPath,
+  });

ee/spec/frontend/ide/lib/create_diff_spec.js

+import { commitActionTypes } from '~/ide/constants';
+import createDiff from 'ee/ide/lib/create_diff';
+import createFileDiff from 'ee/ide/lib/create_file_diff';
+import {
+  createNewFile,
+  createUpdatedFile,
+  createDeletedFile,
+  createMovedFile,
+} from '../file_helpers';
+
+const PATH_FOO = 'test/foo.md';
+const PATH_BAR = 'test/bar.md';
+const PATH_ZED = 'test/zed.md';
+const PATH_LOREM = 'test/lipsum/nested/lorem.md';
+const PATH_IPSUM = 'test/lipsum/ipsum.md';
+const TEXT = `Lorem ipsum dolor sit amet,
+consectetur adipiscing elit.
+Morbi ex dolor, euismod nec rutrum nec, egestas at ligula.
+Praesent scelerisque ut nisi eu eleifend.
+Suspendisse potenti.
+`;
+const LINES = TEXT.trim().split('\n');
+
+const joinDiffs = (...patches) => patches.join('');
+
+describe('EE IDE lib/create_diff', () => {
+  it('with created files, generates patch', () => {
+    const changedFiles = [createNewFile(PATH_FOO, TEXT), createNewFile(PATH_BAR, '')];
+    const result = createDiff({ changedFiles });
+
+    expect(result).toEqual({
+      patch: joinDiffs(
+        createFileDiff(changedFiles[0], commitActionTypes.create),
+        createFileDiff(changedFiles[1], commitActionTypes.create),
+      ),
+      toDelete: [],
+    });
+  });
+
+  it('with deleted files, adds to delete', () => {
+    const changedFiles = [createDeletedFile(PATH_FOO, TEXT), createDeletedFile(PATH_BAR, '')];
+
+    const result = createDiff({ changedFiles });
+
+    expect(result).toEqual({
+      patch: '',
+      toDelete: [PATH_FOO, PATH_BAR],
+    });
+  });
+
+  it('with updated files, generates patch', () => {
+    const changedFiles = [createUpdatedFile(PATH_FOO, TEXT, 'A change approaches!')];
+
+    const result = createDiff({ changedFiles });
+
+    expect(result).toEqual({
+      patch: createFileDiff(changedFiles[0], commitActionTypes.update),
+      toDelete: [],
+    });
+  });
+
+  it('with files in both staged and changed, prefer changed', () => {
+    const changedFiles = [
+      createUpdatedFile(PATH_FOO, TEXT, 'Do a change!'),
+      createDeletedFile(PATH_LOREM),
+    ];
+
+    const result = createDiff({
+      changedFiles,
+      stagedFiles: [createUpdatedFile(PATH_LOREM, TEXT, ''), createDeletedFile(PATH_FOO, TEXT)],
+    });
+
+    expect(result).toEqual({
+      patch: createFileDiff(changedFiles[0], commitActionTypes.update),
+      toDelete: [PATH_LOREM],
+    });
+  });
+
+  it('with file created in staging and deleted in changed, do nothing', () => {
+    const result = createDiff({
+      changedFiles: [createDeletedFile(PATH_FOO)],
+      stagedFiles: [createNewFile(PATH_FOO, TEXT)],
+    });
+
+    expect(result).toEqual({
+      patch: '',
+      toDelete: [],
+    });
+  });
+
+  it('with file deleted in both staged and changed, delete', () => {
+    const result = createDiff({
+      changedFiles: [createDeletedFile(PATH_LOREM)],
+      stagedFiles: [createDeletedFile(PATH_LOREM)],
+    });
+
+    expect(result).toEqual({
+      patch: '',
+      toDelete: [PATH_LOREM],
+    });
+  });
+
+  it('with file moved, create and delete', () => {
+    const changedFiles = [createMovedFile(PATH_BAR, PATH_FOO, TEXT)];
+
+    const result = createDiff({
+      changedFiles,
+      stagedFiles: [createDeletedFile(PATH_FOO)],
+    });
+
+    expect(result).toEqual({
+      patch: createFileDiff(changedFiles[0], commitActionTypes.create),
+      toDelete: [PATH_FOO],
+    });
+  });
+
+  it('with file moved and no content, move', () => {
+    const changedFiles = [createMovedFile(PATH_BAR, PATH_FOO)];
+
+    const result = createDiff({
+      changedFiles,
+      stagedFiles: [createDeletedFile(PATH_FOO)],
+    });
+
+    expect(result).toEqual({
+      patch: createFileDiff(changedFiles[0], commitActionTypes.move),
+      toDelete: [],
+    });
+  });
+
+  it('creates a well formatted patch', () => {
+    const changedFiles = [
+      createMovedFile(PATH_BAR, PATH_FOO),
+      createDeletedFile(PATH_ZED),
+      createNewFile(PATH_LOREM, TEXT),
+      createUpdatedFile(PATH_IPSUM, TEXT, "That's all folks!"),
+    ];
+
+    const expectedPatch = `diff --git "a/${PATH_FOO}" "b/${PATH_BAR}"
+rename from ${PATH_FOO}
+rename to ${PATH_BAR}
+diff --git "a/${PATH_LOREM}" "b/${PATH_LOREM}"
+new file mode 100644
+--- /dev/null
++++ b/${PATH_LOREM}
+@@ -0,0 +1,${LINES.length} @@
+${LINES.map(line => `+${line}`).join('\n')}
+diff --git "a/${PATH_IPSUM}" "b/${PATH_IPSUM}"
+--- a/${PATH_IPSUM}
++++ b/${PATH_IPSUM}
+@@ -1,${LINES.length} +1,1 @@
+${LINES.map(line => `-${line}`).join('\n')}
++That's all folks!
+\\ No newline at end of file
+`;
+
+    const result = createDiff({ changedFiles });
+
+    expect(result).toEqual({
+      patch: expectedPatch,
+      toDelete: [PATH_ZED],
+    });
+  });
+});

ee/spec/frontend/ide/lib/create_file_diff_spec.js

+import { commitActionTypes } from '~/ide/constants';
+import createFileDiff from 'ee/ide/lib/create_file_diff';
+import {
+  createUpdatedFile,
+  createNewFile,
+  createMovedFile,
+  createDeletedFile,
+} from '../file_helpers';
+
+const PATH = 'test/numbers.md';
+const PATH_FOO = 'test/foo.md';
+const TEXT_LINE_COUNT = 100;
+const TEXT = Array(TEXT_LINE_COUNT)
+  .fill(0)
+  .map((_, idx) => `${idx + 1}`)
+  .join('\n');
+
+const spliceLines = (content, lineNumber, deleteCount = 0, newLines = []) => {
+  const lines = content.split('\n');
+  lines.splice(lineNumber, deleteCount, ...newLines);
+  return lines.join('\n');
+};
+
+const mapLines = (content, mapFn) =>
+  content
+    .split('\n')
+    .map(mapFn)
+    .join('\n');
+
+describe('EE IDE lib/create_file_diff', () => {
+  it('returns empty string with "garbage" action', () => {
+    const result = createFileDiff(createNewFile(PATH, ''), 'garbage');
+
+    expect(result).toBe('');
+  });
+
+  it('preserves ending whitespace in file', () => {
+    const oldContent = spliceLines(TEXT, 99, 1, ['100 ']);
+    const newContent = spliceLines(oldContent, 99, 0, ['Lorem', 'Ipsum']);
+    const expected = `
+ 99
++Lorem
++Ipsum
+ 100 `;
+
+    const result = createFileDiff(
+      createUpdatedFile(PATH, oldContent, newContent),
+      commitActionTypes.update,
+    );
+
+    expect(result).toContain(expected);
+  });
+
+  describe('with "create" action', () => {
+    const expectedHead = `diff --git "a/${PATH}" "b/${PATH}"
+new file mode 100644`;
+
+    const expectedChunkHead = lineCount => `--- /dev/null
++++ b/${PATH}
+@@ -0,0 +1,${lineCount} @@`;
+
+    it('with empty file, does not include diff body', () => {
+      const result = createFileDiff(createNewFile(PATH, ''), commitActionTypes.create);
+
+      expect(result).toBe(`${expectedHead}\n`);
+    });
+
+    it('with single line, includes diff body', () => {
+      const result = createFileDiff(createNewFile(PATH, '\n'), commitActionTypes.create);
+
+      expect(result).toBe(`${expectedHead}
+${expectedChunkHead(1)}
++
+`);
+    });
+
+    it('without newline, includes no newline comment', () => {
+      const result = createFileDiff(createNewFile(PATH, 'Lorem ipsum'), commitActionTypes.create);
+
+      expect(result).toBe(`${expectedHead}
+${expectedChunkHead(1)}
++Lorem ipsum
+\\ No newline at end of file
+`);
+    });
+
+    it('with content, includes diff body', () => {
+      const content = `${TEXT}\n`;
+      const result = createFileDiff(createNewFile(PATH, content), commitActionTypes.create);
+
+      expect(result).toBe(`${expectedHead}
+${expectedChunkHead(TEXT_LINE_COUNT)}
+${mapLines(TEXT, line => `+${line}`)}
+`);
+    });
+  });
+
+  describe('with "delete" action', () => {
+    const expectedHead = `diff --git "a/${PATH}" "b/${PATH}"
+deleted file mode 100644`;
+
+    const expectedChunkHead = lineCount => `--- a/${PATH}
++++ /dev/null
+@@ -1,${lineCount} +0,0 @@`;
+
+    it('with empty file, does not include diff body', () => {
+      const result = createFileDiff(createDeletedFile(PATH, ''), commitActionTypes.delete);
+
+      expect(result).toBe(`${expectedHead}\n`);
+    });
+
+    it('with content, includes diff body', () => {
+      const content = `${TEXT}\n`;
+      const result = createFileDiff(createDeletedFile(PATH, content), commitActionTypes.delete);
+
+      expect(result).toBe(`${expectedHead}
+${expectedChunkHead(TEXT_LINE_COUNT)}
+${mapLines(TEXT, line => `-${line}`)}
+`);
+    });
+  });
+
+  describe('with "update" action', () => {
+    it('includes diff body', () => {
+      const oldContent = `${TEXT}\n`;
+      const newContent = `${spliceLines(TEXT, 50, 3, ['Lorem'])}\n`;
+
+      const result = createFileDiff(
+        createUpdatedFile(PATH, oldContent, newContent),
+        commitActionTypes.update,
+      );
+
+      expect(result).toBe(`diff --git "a/${PATH}" "b/${PATH}"
+--- a/${PATH}
++++ b/${PATH}
+@@ -47,11 +47,9 @@
+ 47
+ 48
+ 49
+ 50
+-51
+-52
+-53
++Lorem
+ 54
+ 55
+ 56
+ 57
+`);
+    });
+  });
+
+  describe('with "move" action', () => {
+    it('returns rename head', () => {
+      const result = createFileDiff(createMovedFile(PATH, PATH_FOO), commitActionTypes.move);
+
+      expect(result).toBe(`diff --git "a/${PATH_FOO}" "b/${PATH}"
+rename from ${PATH_FOO}
+rename to ${PATH}
+`);
+    });
+  });
+});