fix: conflicts and strip-dashed

lib/utils/camel-case.ts

@@ -0,0 +1,19 @@
+export function camelCase(s: string) {
+  if (!s) return '';
+  // split camel case, then match ascii words
+  const words = asciiWords(s.replace(/([a-z0-9])([A-Z])/g, '$1 $2'));
+  return words.length > 1
+    ? words[0].toLowerCase() + words.slice(1).map(capitalizeFirst).join('')
+    : words[0].toLowerCase();
+}
+
+function capitalizeFirst(word: string): string {
+  return word ? word[0].toUpperCase() + word.slice(1).toLowerCase() : '';
+}
+
+// eslint-disable-next-line no-control-regex
+const reAsciiWord = /[^\x00-\x2f\x3a-\x40\x5b-\x60\x7b-\x7f]+/g;
+
+function asciiWords(s: string) {
+  return s.match(reAsciiWord) || [];
+}

lib/validation.ts

@@ -6,6 +6,7 @@ import {
 } from './typings/common-types.js';
 import {levenshtein as distance} from './utils/levenshtein.js';
 import {objFilter} from './utils/obj-filter.js';
+import {camelCase} from './utils/camel-case.js';
 import {UsageInstance} from './usage.js';
 import {YargsInstance, Arguments} from './yargs-factory.js';
 import {DetailedArguments} from './typings/yargs-parser-types.js';
@@ -411,6 +412,24 @@ export function validation(
         });
       }
     });
+
+    // When strip-dashed is true, match conflicts (kebab) with argv (camel)
+    // Addresses: https://github.com/yargs/yargs/issues/1952
+    if (yargs.getInternalMethods().getParserConfiguration()['strip-dashed']) {
+      Object.keys(conflicting).forEach(key => {
+        conflicting[key].forEach(value => {
+          if (
+            value &&
+            argv[camelCase(key)] !== undefined &&
+            argv[camelCase(value)] !== undefined
+          ) {
+            usage.fail(
+              __('Arguments %s and %s are mutually exclusive', key, value)
+            );
+          }
+        });
+      });
+    }
   };
 
   self.recommendCommands = function recommendCommands(cmd, potentialCommands) {

test/validation.cjs

@@ -204,6 +204,27 @@ describe('validation tests', () => {
         .parse();
     });
 
+    // Addresses: https://github.com/yargs/yargs/issues/1952
+    it('fails if conflicting arguments are provided, and strip-dashed is enabled', () => {
+      yargs()
+        .option('foo-foo', {
+          description: 'a foo-foo',
+          type: 'string',
+        })
+        .option('bar-bar', {
+          description: 'a bar-bar',
+          type: 'string',
+        })
+        .conflicts({'foo-foo': 'bar-bar'})
+        .parserConfiguration({'strip-dashed': true})
+        .parse('--foo-foo a --bar-bar b', (error, argv, output) => {
+          expect(error).to.not.equal(null);
+          error.message.should.match(
+            /Arguments foo-foo and bar-bar are mutually exclusive/
+          );
+        });
+    });
+
     it('should not fail if no conflicting arguments are provided', () => {
       yargs(['-b', '-c'])
         .conflicts('f', ['b', 'c'])