add updater for python readme

src/strategies/python.ts

@@ -26,6 +26,7 @@ import {
 import {PythonFileWithVersion} from '../updaters/python/python-file-with-version';
 import {FileNotFoundError} from '../errors';
 import {filterCommits} from '../util/filter-commits';
+import {PythonReadme} from '../updaters/python/python-readme';
 
 const CHANGELOG_SECTIONS = [
   {type: 'feat', section: 'Features'},
@@ -79,6 +80,14 @@ export class Python extends BaseStrategy {
       }),
     });
 
+    updates.push({
+      path: this.addPath('README.md'),
+      createIfMissing: false,
+      updater: new PythonReadme({
+        version,
+      }),
+    });
+
     const parsedPyProject = await this.getPyProject(
       this.addPath('pyproject.toml')
     );

src/updaters/python/python-readme.ts

@@ -0,0 +1,27 @@
+import {DefaultUpdater} from '../default';
+
+/**
+ * Updates a README.md file
+ */
+export class PythonReadme extends DefaultUpdater {
+  /**
+   * Given initial file contents, return updated contents.
+   * @param {string} content The initial content
+   * @returns {string} The updated content
+   */
+  updateContent(content: string): string {
+    if (this.version.preRelease) {
+      // it's a pre-release, so add the pre-release flag if it's missing
+      return content.replace(
+        /^# install from PyPI\n^pip install (\S+)$/gm,
+        '# install from PyPI\npip install --pre $1'
+      );
+    } else {
+      // it's not a pre-release, so remove the pre-release flag if it's present
+      return content.replace(
+        /^# install from PyPI\n^pip install --pre (\S+)$/gm,
+        '# install from PyPI\npip install $1'
+      );
+    }
+  }
+}

test/strategies/python.ts

@@ -28,6 +28,8 @@ import {SetupPy} from '../../src/updaters/python/setup-py';
 import {Changelog} from '../../src/updaters/changelog';
 import {ChangelogJson} from '../../src/updaters/changelog-json';
 import snapshot = require('snap-shot-it');
+import {PullRequestBody} from '../../src/util/pull-request-body';
+import {PythonReadme} from '../../src/updaters/python/python-readme';
 
 const sandbox = sinon.createSandbox();
 const fixturesPath = './test/fixtures/strategies/python';
@@ -164,6 +166,39 @@ describe('Python', () => {
       assertHasUpdate(updates, 'pyproject.toml', PyProjectToml);
     });
 
+    it('finds and updates a README.md', async () => {
+      const strategy = new Python({
+        targetBranch: 'main',
+        github,
+        component: 'google-cloud-automl',
+      });
+      sandbox
+        .stub(github, 'getFileContentsOnBranch')
+        .resolves(
+          buildGitHubFileContent(
+            './test/updaters/fixtures',
+            'README-python-pre.md'
+          )
+        );
+      sandbox.stub(github, 'findFilesByFilenameAndRef').resolves([]);
+      const release = await strategy.buildReleasePullRequest({
+        commits: COMMITS,
+        latestRelease: await strategy.buildRelease({
+          title: 'chore(main): release v1.2.3',
+          headBranchName: 'release-please/branches/main',
+          baseBranchName: 'main',
+          number: 1234,
+          body: new PullRequestBody([]).toString(),
+          labels: [],
+          files: [],
+          sha: 'abc123',
+        }),
+      });
+      const updates = release!.updates;
+
+      assertHasUpdate(updates, 'README.md', PythonReadme);
+    });
+
     it('finds and updates a version.py file', async () => {
       const strategy = new Python({
         targetBranch: 'main',

test/updaters/fixtures/README-python-no-pre.md

@@ -0,0 +1,6 @@
+## Installation
+
+```sh
+# install from PyPI
+pip install test-repo
+```

test/updaters/fixtures/README-python-pre.md

@@ -0,0 +1,6 @@
+## Installation
+
+```sh
+# install from PyPI
+pip install --pre test-repo
+```

test/updaters/python-readme.ts

@@ -0,0 +1,50 @@
+import {readFileSync} from 'fs';
+import {resolve} from 'path';
+import {describe, it} from 'mocha';
+import {expect} from 'chai';
+import {Version} from '../../src/version';
+import {PythonReadme} from '../../src/updaters/python/python-readme';
+
+const fixturesPath = './test/updaters/fixtures';
+
+describe('PythonReadme', () => {
+  const withPreFlag = readFileSync(
+    resolve(fixturesPath, 'README-python-pre.md'),
+    'utf8'
+  );
+
+  const withoutPreFlag = readFileSync(
+    resolve(fixturesPath, 'README-python-no-pre.md'),
+    'utf8'
+  );
+
+  it('makes no changes if there is a --pre on the install instructions in a README for a prerelease version', async () => {
+    const readmeUpdater = new PythonReadme({
+      version: Version.parse('0.6.0-alpha.1'),
+    });
+    expect(readmeUpdater.updateContent(withPreFlag)).to.equal(withPreFlag);
+  });
+
+  it('makes no changes if there is no --pre on the install instructions in a README for a non-prerelease version', async () => {
+    const readmeUpdater = new PythonReadme({
+      version: Version.parse('0.6.0'),
+    });
+    expect(readmeUpdater.updateContent(withoutPreFlag)).to.equal(
+      withoutPreFlag
+    );
+  });
+
+  it('adds --pre if there is no --pre on the install instructions in a README for a prerelease version', async () => {
+    const readmeUpdater = new PythonReadme({
+      version: Version.parse('0.6.0-alpha.1'),
+    });
+    expect(readmeUpdater.updateContent(withoutPreFlag)).to.equal(withPreFlag);
+  });
+
+  it('removes --pre if there is a --pre on the install instructions in a README for a non-prerelease version', async () => {
+    const readmeUpdater = new PythonReadme({
+      version: Version.parse('0.6.0'),
+    });
+    expect(readmeUpdater.updateContent(withPreFlag)).to.equal(withoutPreFlag);
+  });
+});