fix(core): detect kmscon terminal as supporting true color (#25282)

Co-authored-by: Adib234 <30782825+Adib234@users.noreply.github.com>
Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

packages/core/src/utils/compatibility.test.ts

@@ -195,6 +195,7 @@ describe('compatibility', () => {
         desc: '256 colors are not supported',
       },
     ])('should return $expected when $desc', ({ depth, term, expected }) => {
+      vi.stubEnv('COLORTERM', '');
       process.stdout.getColorDepth = vi.fn().mockReturnValue(depth);
       if (term !== undefined) {
         vi.stubEnv('TERM', term);
@@ -203,6 +204,13 @@ describe('compatibility', () => {
       }
       expect(supports256Colors()).toBe(expected);
     });
+
+    it('should return true when COLORTERM is kmscon', () => {
+      process.stdout.getColorDepth = vi.fn().mockReturnValue(4);
+      vi.stubEnv('TERM', 'linux');
+      vi.stubEnv('COLORTERM', 'kmscon');
+      expect(supports256Colors()).toBe(true);
+    });
   });
 
   describe('supportsTrueColor', () => {
@@ -230,6 +238,12 @@ describe('compatibility', () => {
         expected: true,
         desc: 'getColorDepth returns >= 24',
       },
+      {
+        colorterm: 'kmscon',
+        depth: 4,
+        expected: true,
+        desc: 'COLORTERM is kmscon',
+      },
       {
         colorterm: '',
         depth: 8,
@@ -409,6 +423,18 @@ describe('compatibility', () => {
       );
     });
 
+    it('should return no color warnings for kmscon terminal', () => {
+      vi.mocked(os.platform).mockReturnValue('linux');
+      vi.stubEnv('TERMINAL_EMULATOR', '');
+      vi.stubEnv('TERM', 'linux');
+      vi.stubEnv('COLORTERM', 'kmscon');
+      process.stdout.getColorDepth = vi.fn().mockReturnValue(4);
+
+      const warnings = getCompatibilityWarnings();
+      expect(warnings.find((w) => w.id === '256-color')).toBeUndefined();
+      expect(warnings.find((w) => w.id === 'true-color')).toBeUndefined();
+    });
+
     it('should return no warnings in a standard environment with true color', () => {
       vi.mocked(os.platform).mockReturnValue('darwin');
       vi.stubEnv('TERMINAL_EMULATOR', '');

packages/core/src/utils/compatibility.ts

@@ -85,6 +85,11 @@ export function supports256Colors(): boolean {
     return true;
   }
 
+  // Terminals supporting true color (like kmscon) also support 256 colors
+  if (supportsTrueColor()) {
+    return true;
+  }
+
   return false;
 }
 
@@ -95,7 +100,8 @@ export function supportsTrueColor(): boolean {
   // Check COLORTERM environment variable
   if (
     process.env['COLORTERM'] === 'truecolor' ||
-    process.env['COLORTERM'] === '24bit'
+    process.env['COLORTERM'] === '24bit' ||
+    process.env['COLORTERM'] === 'kmscon'
   ) {
     return true;
   }