feat: get last release with git tags

- Remove the `getLastRelease` plugin type
- Retrieve the last release based on Git tags
- Create the next release Git tag before calling the `publish` plugins

BREAKING CHANGE: Remove the `getLastRelease` plugin type

The `getLastRelease` plugins will not be called anymore.

BREAKING CHANGE: Git repository authentication is now mandatory

The Git authentication is now mandatory and must be set via `GH_TOKEN`, `GITHUB_TOKEN`,  `GL_TOKEN`, `GITLAB_TOKEN` or `GIT_CREDENTIALS` as described in [CI configuration](https://github.com/semantic-release/semantic-release/blob/caribou/docs/usage/ci-configuration.md#authentication).

lib/git.js

@@ -1,6 +1,5 @@
 const execa = require('execa');
 const debug = require('debug')('semantic-release:get-version-head');
-const {debugShell} = require('./debug');
 
 /**
  * Get the commit sha for a given tag.
@@ -10,45 +9,29 @@ const {debugShell} = require('./debug');
  * @return {string} The commit sha of the tag in parameter or `null`.
  */
 async function gitTagHead(tagName) {
-  try {
-    const shell = await execa('git', ['rev-list', '-1', tagName]);
-    debugShell('Get git tag head', shell, debug);
-    return shell.stdout;
-  } catch (err) {
-    debug(err);
-    return null;
-  }
+  return execa.stdout('git', ['rev-list', '-1', tagName], {reject: false});
 }
 
 /**
- * Get the tag associated with a commit sha.
- *
- * @param {string} gitHead The commit sha for which to retrieve the associated tag.
- *
- * @return {string} The tag associatedwith the sha in parameter or `undefined`.
+ * @return {Array<String>} List of git tags.
+ * @throws {Error} If the `git` command fails.
  */
-async function gitCommitTag(gitHead) {
-  try {
-    const shell = await execa('git', ['describe', '--tags', '--exact-match', gitHead]);
-    debugShell('Get git commit tag', shell, debug);
-    return shell.stdout;
-  } catch (err) {
-    debug(err);
-    return undefined;
-  }
+async function gitTags() {
+  return (await execa.stdout('git', ['tag']))
+    .split('\n')
+    .map(tag => tag.trim())
+    .filter(tag => Boolean(tag));
 }
 
 /**
- * Verify if the commit `sha` is in the direct history of the current branch.
+ * Verify if the `ref` is in the direct history of the current branch.
  *
- * @param {string} sha The sha of the commit to look for.
+ * @param {string} ref The reference to look for.
  *
- * @return {boolean} `true` if the commit `sha` is in the history of the current branch, `false` otherwise.
+ * @return {boolean} `true` if the reference is in the history of the current branch, `false` otherwise.
  */
-async function isCommitInHistory(sha) {
-  const shell = await execa('git', ['merge-base', '--is-ancestor', sha, 'HEAD'], {reject: false});
-  debugShell('Check if commit is in history', shell, debug);
-  return shell.code === 0;
+async function isRefInHistory(ref) {
+  return (await execa('git', ['merge-base', '--is-ancestor', ref, 'HEAD'], {reject: false})).code === 0;
 }
 
 /**
@@ -62,30 +45,83 @@ async function unshallow() {
  * @return {string} the sha of the HEAD commit.
  */
 async function gitHead() {
-  try {
-    const shell = await execa('git', ['rev-parse', 'HEAD']);
-    debugShell('Get git head', shell, debug);
-    return shell.stdout;
-  } catch (err) {
-    debug(err);
-    throw new Error(err.stderr);
-  }
+  return execa.stdout('git', ['rev-parse', 'HEAD']);
 }
 
 /**
- * @return {string|undefined} The value of the remote git URL.
+ * @return {string} The value of the remote git URL.
  */
 async function repoUrl() {
-  return (await execa.stdout('git', ['remote', 'get-url', 'origin'], {reject: false})) || undefined;
+  return execa.stdout('git', ['remote', 'get-url', 'origin'], {reject: false});
 }
 
 /**
  * @return {Boolean} `true` if the current working directory is in a git repository, `false` otherwise.
  */
 async function isGitRepo() {
-  const shell = await execa('git', ['rev-parse', '--git-dir'], {reject: false});
-  debugShell('Check if the current working directory is a git repository', shell, debug);
-  return shell.code === 0;
+  return (await execa('git', ['rev-parse', '--git-dir'], {reject: false})).code === 0;
 }
 
-module.exports = {gitTagHead, gitCommitTag, isCommitInHistory, unshallow, gitHead, repoUrl, isGitRepo};
+/**
+ * Verify the write access authorization to remote repository with push dry-run.
+ *
+ * @param {String} origin The remote repository URL.
+ * @param {String} branch The repositoru branch for which to verify write access.
+ *
+ * @return {Boolean} `true` is authorized to push, `false` otherwise.
+ */
+async function verifyAuth(origin, branch) {
+  return (await execa('git', ['push', '--dry-run', origin, `HEAD:${branch}`], {reject: false})).code === 0;
+}
+
+/**
+ * Tag the commit head on the local repository.
+ *
+ * @param {String} tagName The name of the tag.
+ * @throws {Error} if the tag creation failed.
+ */
+async function tag(tagName) {
+  await execa('git', ['tag', tagName]);
+}
+
+/**
+ * Push to the remote repository.
+ *
+ * @param {String} origin The remote repository URL.
+ * @param {String} branch The branch to push.
+ * @throws {Error} if the push failed.
+ */
+async function push(origin, branch) {
+  await execa('git', ['push', '--tags', origin, `HEAD:${branch}`]);
+}
+
+/**
+ * Delete a tag locally and remotely.
+ *
+ * @param {String} origin The remote repository URL.
+ * @param {String} tagName The tag name to delete.
+ * @throws {SemanticReleaseError} if the remote tag exists and references a commit that is not the local head commit.
+ */
+async function deleteTag(origin, tagName) {
+  // Delete the local tag
+  let shell = await execa('git', ['tag', '-d', tagName], {reject: false});
+  debug('delete local tag', shell);
+
+  // Delete the tag remotely
+  shell = await execa('git', ['push', '-d', origin, tagName], {reject: false});
+  debug('delete remote tag', shell);
+}
+
+module.exports = {
+  gitTagHead,
+  gitTags,
+  isRefInHistory,
+  unshallow,
+  gitHead,
+  repoUrl,
+  isGitRepo,
+  verifyAuth,
+  tag,
+  push,
+  deleteTag,
+};