Fix navigation dropdowns

[reakaleek]

Problem

In assembler builds, navigation folders with the same relative path from different documentation sets were generating duplicate HTML id attributes. This breaks the HTML specification and causes accessibility issues with <label for> and <input id> pairings in the navigation template (_TocTreeNav.cshtml).

Example: Two docsets both have a getting-started folder. When assembled, both folders received the same ID, causing invalid HTML.

Root Cause

Navigation node IDs were generated using only the relative path:

• FolderNavigation: ShortId.Create(parentPath)
• VirtualFileNavigation: ShortId.Create(RelativePathToDocumentationSet)
• TableOfContentsNavigation: ShortId.Create(parentPath)

In assembler builds, multiple docsets can have folders with identical relative paths (e.g., both have getting-started), resulting in duplicate IDs.

Solution

Changed ID generation to include both the navigation root identifier and the URL:

• ShortId.Create(NavigationRoot.Id, Index.Url)

This ensures uniqueness because:

• NavigationRoot.Id is unique per docset (based on project name)
• Index.Url is unique within each docset

Testing

Added a test NavigationNodeIdsAreUniqueAcrossDocsets that:

1. Creates two docsets with identical folder structures
2. Assembles them using SiteNavigation (production code)
3. Verifies all node IDs are unique using production YieldAll() traversal

The test follows TDD: it fails with the original code and passes with the fix.