fix: handle case rules for numerics correctly

* fix(ensure): return true for values starting with numeric character

* fix(rules): ignore values starting with non-alphabetic character

@commitlint/ensure/src/case.js

@@ -14,7 +14,7 @@ function ensureCase(raw = '', target = 'lowercase') {
 		.trim();
 	const transformed = toCase(input, target);
 
-	if (transformed === '') {
+	if (transformed === '' || transformed.match(/^\d/)) {
 		return true;
 	}
 
@@ -38,7 +38,7 @@ function toCase(input, target) {
 			return input.toUpperCase();
 		case 'sentence-case':
 		case 'sentencecase': {
-			const word = input.split(' ')[0];
+			const [word] = input.split(' ');
 			return `${toCase(word.charAt(0), 'upper-case')}${toCase(
 				word.slice(1),
 				'lower-case'

@commitlint/ensure/src/case.test.js

@@ -291,3 +291,31 @@ test('false for `LOWERCASE on lowercase', t => {
 	const actual = ensure('`LOWERCASE', 'lowercase');
 	t.is(actual, false);
 });
+
+test('true for numeric on camel-case', t => {
+	t.true(ensure('1.0.0', 'camel-case'));
+});
+
+test('true for numeric on kebab-case', t => {
+	t.true(ensure('1.0.0', 'kebab-case'));
+});
+
+test('true for numeric on snake-case', t => {
+	t.true(ensure('1.0.0', 'snake-case'));
+});
+
+test('true for numeric on pascal-case', t => {
+	t.true(ensure('1.0.0', 'pascal-case'));
+});
+
+test('true for numeric on uppercase', t => {
+	t.true(ensure('1.0.0', 'uppercase'));
+});
+
+test('true for numeric on sentencecase', t => {
+	t.true(ensure('1.0.0', 'sentencecase'));
+});
+
+test('true for numeric on lowercase', t => {
+	t.true(ensure('1.0.0', 'lowercase'));
+});

@commitlint/rules/src/subject-case.js

@@ -6,7 +6,7 @@ const negated = when => when === 'never';
 export default (parsed, when, value) => {
 	const {subject} = parsed;
 
-	if (typeof subject !== 'string') {
+	if (typeof subject !== 'string' || !subject.match(/^[a-z]/i)) {
 		return [true];
 	}
 

@commitlint/rules/src/subject-case.test.js

@@ -4,6 +4,7 @@ import subjectCase from './subject-case';
 
 const messages = {
 	empty: 'test:\n',
+	numeric: 'test: 1.0.0',
 	lowercase: 'test: subject',
 	mixedcase: 'test: sUbJeCt',
 	uppercase: 'test: SUBJECT',
@@ -16,6 +17,7 @@ const messages = {
 
 const parsed = {
 	empty: parse(messages.empty),
+	numeric: parse(messages.numeric),
 	lowercase: parse(messages.lowercase),
 	mixedcase: parse(messages.mixedcase),
 	uppercase: parse(messages.uppercase),
@@ -324,3 +326,27 @@ test('with uppercase scope should fail for "never [uppercase, lowercase]"', asyn
 	const expected = false;
 	t.is(actual, expected);
 });
+
+test('with numeric subject should succeed for "never lowercase"', async t => {
+	const [actual] = subjectCase(await parsed.numeric, 'never', 'lowercase');
+	const expected = true;
+	t.is(actual, expected);
+});
+
+test('with numeric subject should succeed for "always lowercase"', async t => {
+	const [actual] = subjectCase(await parsed.numeric, 'always', 'lowercase');
+	const expected = true;
+	t.is(actual, expected);
+});
+
+test('with numeric subject should succeed for "never uppercase"', async t => {
+	const [actual] = subjectCase(await parsed.numeric, 'never', 'uppercase');
+	const expected = true;
+	t.is(actual, expected);
+});
+
+test('with numeric subject should succeed for "always uppercase"', async t => {
+	const [actual] = subjectCase(await parsed.numeric, 'always', 'uppercase');
+	const expected = true;
+	t.is(actual, expected);
+});