fix: replace inIfStatement boolean with depth counter in getLiquidIfVersionTokens (#62299)

Co-authored-by: docs-engineering-bot[bot] <285023527+docs-engineering-bot[bot]@users.noreply.github.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>

Author: 3 people

src/content-linter/lib/helpers/liquid-utils.ts

@@ -123,20 +123,26 @@ export function getLiquidIfVersionTokens(content: string): TagToken[] {
     .filter((token): token is TagToken => token.kind === TokenKind.Tag)
     .filter((token) => IFVERSION_TAG_NAMES.includes(token.name))
 
-  let inIfStatement = false
+  let ifDepth = 0
   let inCaseStatement = false
   const ifVersionTokens: TagToken[] = []
   for (const token of tokens) {
-    // Filter out `if` statements and their related tags
+    // Filter out `if` statements and their related tags (supports nesting)
     if (token.name === 'if') {
-      inIfStatement = true
+      ifDepth++
       continue
     }
-    if (inIfStatement && token.name !== 'endif') continue
-    if (inIfStatement && token.name === 'endif') {
-      inIfStatement = false
+    // While we're inside a regular if subtree, `endif` can close either
+    // `if` or `ifversion`, so count nested `ifversion` tags too.
+    if (ifDepth > 0 && token.name === 'ifversion') {
+      ifDepth++
       continue
     }
+    if (ifDepth > 0 && token.name === 'endif') {
+      ifDepth--
+      continue
+    }
+    if (ifDepth > 0) continue
     // Filter out `case` statements and their related tags (including `else`)
     if (token.name === 'case') {
       inCaseStatement = true

src/content-linter/tests/unit/liquid-ifversion-versions.ts

@@ -139,6 +139,76 @@ describe(liquidIfversionVersions.names.join(' - '), () => {
     const errors = result.markdown
     expect(errors.length).toBe(0)
   })
+
+  test('does not crash with nested if blocks inside ifversion', async () => {
+    const markdown = [
+      ...placeholderAllVersionsFm,
+      '{% ifversion ghec %}',
+      '  {% if "foo" %}',
+      '    {% if "bar" %}nested{% endif %}',
+      '  {% endif %}',
+      '{% endif %}',
+    ].join('\n')
+
+    const result = await runRule(liquidIfversionVersions, {
+      strings: { markdown },
+    })
+    // No crash; zero errors expected for valid ifversion usage
+    const errors = result.markdown
+    expect(errors.length).toBe(0)
+  })
+
+  test('does not crash with nested if blocks at top level', async () => {
+    const markdown = [
+      ...placeholderAllVersionsFm,
+      '{% if "foo" %}',
+      '  {% if "bar" %}...{% endif %}',
+      '{% endif %}',
+    ].join('\n')
+
+    const result = await runRule(liquidIfversionVersions, {
+      strings: { markdown },
+    })
+    const errors = result.markdown
+    expect(errors.length).toBe(0)
+  })
+
+  test('does not crash with ifversion nested inside if blocks', async () => {
+    const markdown = [
+      ...placeholderAllVersionsFm,
+      '{% if "foo" %}',
+      '  {% ifversion ghec %}',
+      '  {% endif %}',
+      '{% endif %}',
+    ].join('\n')
+
+    const result = await runRule(liquidIfversionVersions, {
+      strings: { markdown },
+    })
+    const errors = result.markdown
+    expect(errors.length).toBe(0)
+  })
+
+  test('does not crash with mixed if/ifversion nesting and else branches', async () => {
+    const markdown = [
+      ...placeholderAllVersionsFm,
+      '{% if "foo" %}',
+      '  {% ifversion ghec %}',
+      '    {% if "bar" %}nested{% endif %}',
+      '  {% else %}',
+      '    text',
+      '  {% endif %}',
+      '{% else %}',
+      '  top-level else',
+      '{% endif %}',
+    ].join('\n')
+
+    const result = await runRule(liquidIfversionVersions, {
+      strings: { markdown },
+    })
+    const errors = result.markdown
+    expect(errors.length).toBe(0)
+  })
 })
 
 describe.skip('test validateIfversionConditionalsVersions function', () => {