fix(validators): per-label 63-char check; drop trailing period

Bugbot follow-ups on PR #573.

1. validateHelmReleaseName length error trailed with a period.
   The ValidationResult contract is 'no trailing period — call
   sites compose them into sentences', and InstallWizard does
   exactly that ('Release name {error}.'), producing '...limit..'
   in the UI when a user typed > 53 chars.

2. validateRFC1123Subdomain only checked total length (≤ 253) and
   the 'segments' regex, so a single 200-char label passed
   client-side and was rejected only server-side. K8s'
   IsDNS1123Subdomain enforces ≤ 63 PER label on top of the 253
   total. Add the per-label check and pin it under 'each
   dot-separated label must be at most 63 characters'.

Made-with: Cursor

Author: eliran-mic

packages/k8s-ui/src/utils/validators.test.ts

@@ -81,6 +81,27 @@ describe('validateRFC1123Subdomain', () => {
     expect(r.valid).toBe(false)
     if (!r.valid) expect(r.error).toMatch(/253/)
   })
+
+  it('rejects single labels longer than 63 chars even when total is under 253', () => {
+    // K8s' IsDNS1123Subdomain enforces ≤ 63 chars per dot-
+    // separated label on top of the 253-char total. Without the
+    // per-label check, a single 200-char label slipped through
+    // client-side and was rejected only server-side.
+    const huge = 'a'.repeat(200)
+    const r = validateRFC1123Subdomain(huge)
+    expect(r.valid).toBe(false)
+    if (!r.valid) expect(r.error).toMatch(/63/)
+  })
+
+  it('accepts a 63-char label at the boundary', () => {
+    expect(validateRFC1123Subdomain('a'.repeat(63)).valid).toBe(true)
+  })
+
+  it('rejects only the offending label when other labels are fine', () => {
+    const r = validateRFC1123Subdomain(`ok.${'a'.repeat(64)}.also-ok`)
+    expect(r.valid).toBe(false)
+    if (!r.valid) expect(r.error).toMatch(/63/)
+  })
 })
 
 describe('validateHelmReleaseName', () => {
@@ -103,6 +124,17 @@ describe('validateHelmReleaseName', () => {
   it('accepts a name exactly 53 characters long (boundary)', () => {
     expect(validateHelmReleaseName('a'.repeat(53)).valid).toBe(true)
   })
+
+  it('error string has no trailing period (call-site composition convention)', () => {
+    // ValidationResult contract: error strings have no trailing
+    // period — the caller composes them into sentences and adds
+    // its own. InstallWizard renders `Release name {error}.` so a
+    // trailing period in this error string produced "...limit.." in
+    // the UI when a user exceeded the cap.
+    const r = validateHelmReleaseName('a'.repeat(54))
+    if (r.valid) throw new Error('expected invalid')
+    expect(r.error.endsWith('.')).toBe(false)
+  })
 })
 
 describe('validatePort', () => {

packages/k8s-ui/src/utils/validators.ts

@@ -90,6 +90,18 @@ export function validateRFC1123Subdomain(input: string): ValidationResult {
       error: 'must contain only lowercase letters, numbers, hyphens, and dots, and each segment must start/end with a letter or number',
     }
   }
+  // Per-label cap: K8s' IsDNS1123Subdomain enforces ≤ 63 chars
+  // PER dot-separated label on top of the 253-char total. The
+  // regex above doesn't catch that; without this check a single
+  // 200-char label passes here and only fails server-side.
+  for (const label of input.split('.')) {
+    if (label.length > RFC1123_LABEL_MAX) {
+      return {
+        valid: false,
+        error: `each dot-separated label must be at most ${RFC1123_LABEL_MAX} characters (got ${label.length} for "${label}")`,
+      }
+    }
+  }
   return { valid: true }
 }
 
@@ -105,7 +117,10 @@ export function validateHelmReleaseName(input: string): ValidationResult {
   if (input.length > HELM_RELEASE_NAME_MAX) {
     return {
       valid: false,
-      error: `must be at most ${HELM_RELEASE_NAME_MAX} characters (got ${input.length}). Helm caps release names so derived resource names fit under K8s' 63-char limit.`,
+      // No trailing period — call sites compose this into a
+      // sentence and append their own. Bugbot caught the
+      // double-period UI in InstallWizard.
+      error: `must be at most ${HELM_RELEASE_NAME_MAX} characters (got ${input.length}); Helm caps release names so derived resource names fit under K8s' 63-char limit`,
     }
   }
   return validateRFC1123Subdomain(input)