feat(cli): commit hash validation

Fixes conventional-changelog#3376

Author: Mersho

@commitlint/cli/package.json

@@ -56,6 +56,7 @@
     "lodash.isfunction": "^3.0.9",
     "resolve-from": "5.0.0",
     "resolve-global": "1.0.0",
+    "simple-git": "^3.22.0",
     "yargs": "^17.0.0"
   },
   "gitHead": "70f7f4688b51774e7ac5e40e896cdaa3f132b2bc"

@commitlint/cli/src/cli.ts

@@ -2,6 +2,7 @@ import execa, {ExecaError} from 'execa';
 import load from '@commitlint/load';
 import lint from '@commitlint/lint';
 import read from '@commitlint/read';
+import {simpleGit} from 'simple-git';
 import isFunction from 'lodash.isfunction';
 import resolveFrom from 'resolve-from';
 import resolveGlobal from 'resolve-global';
@@ -213,16 +214,39 @@ async function main(args: MainArgs): Promise<void> {
 		throw err;
 	}
 
-	const input = await (fromStdin
-		? stdin()
-		: read({
-				to: flags.to,
-				from: flags.from,
-				edit: flags.edit,
-				cwd: flags.cwd,
-				gitLogArgs: flags['git-log-args'],
-		  }));
+	if (flags.from != null && flags.to != null && flags.from === flags.to) {
+		const err = new CliError(
+			'Please use a different commit hash for --from and --to, not the same. (Or use the --last flag for analyzing just the last commit.)',
+			pkg.name
+		);
+		yargs.showHelp('log');
+		console.log(err.message);
+		throw err;
+	}
+
+	let input;
 
+	if (flags.last != null) {
+		const log = await simpleGit({baseDir: flags.cwd}).log({
+			maxCount: 1,
+		});
+		input = '';
+		if (log.latest) {
+			input = log.latest.message;
+		} else {
+			throw new CliError('No commits found in the repository.', pkg.name);
+		}
+	} else {
+		input = await (fromStdin
+			? stdin()
+			: read({
+					to: flags.to,
+					from: flags.from,
+					edit: flags.edit,
+					cwd: flags.cwd,
+					gitLogArgs: flags['git-log-args'],
+			  }));
+	}
 	const messages = (Array.isArray(input) ? input : [input])
 		.filter((message) => typeof message === 'string')
 		.filter((message) => message.trim() !== '')

yarn.lock

@@ -628,6 +628,18 @@
     "@jridgewell/resolve-uri" "^3.1.0"
     "@jridgewell/sourcemap-codec" "^1.4.14"
 
+"@kwsites/file-exists@^1.1.1":
+  version "1.1.1"
+  resolved "https://registry.npmjs.org/@kwsites/file-exists/-/file-exists-1.1.1.tgz#ad1efcac13e1987d8dbaf235ef3be5b0d96faa99"
+  integrity sha512-m9/5YGR18lIwxSFDwfE3oA7bWuq9kdau6ugN4H2rJeyhFQZcG9AgSHkQtSD15a8WvTgfz9aikZMrKPHvbpqFiw==
+  dependencies:
+    debug "^4.1.1"
+
+"@kwsites/promise-deferred@^1.1.1":
+  version "1.1.1"
+  resolved "https://registry.npmjs.org/@kwsites/promise-deferred/-/promise-deferred-1.1.1.tgz#8ace5259254426ccef57f3175bc64ed7095ed919"
+  integrity sha512-GaHYm+c0O9MjZRu0ongGBRbinu8gVAMd2UZjji6jVmqKtZluZnptXGWhz1E8j8D2HJ3f/yMxKAUC0b+57wncIw==
+
 "@lerna/[email protected]":
   version "6.4.1"
   resolved "https://registry.npmjs.org/@lerna/add/-/add-6.4.1.tgz#fa20fe9ff875dc5758141262c8cde0d9a6481ec4"
@@ -8007,6 +8019,15 @@ signal-exit@^4.1.0:
   resolved "https://registry.npmjs.org/signal-exit/-/signal-exit-4.1.0.tgz#952188c1cbd546070e2dd20d0f41c0ae0530cb04"
   integrity sha512-bzyZ1e88w9O1iNJbKnOlvYTrWPDl46O1bG0D3XInv+9tkPrxrN8jUUTiFlDkkmKWgn1M6CfIA13SuGqOa9Korw==
 
+simple-git@^3.22.0:
+  version "3.22.0"
+  resolved "https://registry.npmjs.org/simple-git/-/simple-git-3.22.0.tgz#616d41c661e30f9c65778956317d422b1729a242"
+  integrity sha512-6JujwSs0ac82jkGjMHiCnTifvf1crOiY/+tfs/Pqih6iow7VrpNKRRNdWm6RtaXpvvv/JGNYhlUtLhGFqHF+Yw==
+  dependencies:
+    "@kwsites/file-exists" "^1.1.1"
+    "@kwsites/promise-deferred" "^1.1.1"
+    debug "^4.3.4"
+
 sisteransi@^1.0.5:
   version "1.0.5"
   resolved "https://registry.npmjs.org/sisteransi/-/sisteransi-1.0.5.tgz#134d681297756437cc05ca01370d3a7a571075ed"