# nav-golden-hierarchy — hierarchical navigation golden

Fixture class **nav-golden** (commons-owned, per the D4 step-0 split): `bundle/` in,
`expected-read-context.md` out. Unlike the ingest-golden class (ingest-spec §11,
extraction-shaped: `manifest.json` → `expected-bundle/`), a nav-golden case is
**bundle → read-context** — the only shape that can express the load-bearing property
"two conformant implementations MUST produce an identical read-context from the same
bundle" (method-spec §3 Step 1).

This **positive** case exercises every decision the Q3 navigation contract pins:

| Decision (method-spec §3 Step 1) | How this bundle exercises it |
|---|---|
| Hierarchy allowed; escape, not depth, forbidden | `a/`, `a/b/` are navigated; nothing escapes |
| Link syntax: leading `/` = bundle root, else relative | `index.md`: relative `overview.md` + root-relative `/a/index.md`; `a/index.md`: relative `b/index.md` + root-relative `/overview.md` |
| Depth-first, first-seen order | render order is `overview` → `doc-a` → `doc-b` |
| Dedup on resolved path | `/overview.md` (from `a/`) resolves to the already-seen `overview.md` → one entry |
| Cycle termination | `a/b/index.md` links back to `/a/index.md` (already seen) → stops |
| One segment per level | each index links only its immediate children |
| Missing `index.md` binds the root alone | `c/` has no `index.md` and nothing links `c/orphan.md`; it is simply unreachable, not an error |
| Verdict exclusion = type check per reached file, recursive | `a/verdict-nested.md` is reached but excluded |
| Flat render regardless of depth | nested concepts render as the same `## {type}: {title}` sections; no level heading; nested index bodies are navigation, not content, and are not rendered |

**Traversal trace:** `index.md` (its body is the leading summary) → `overview.md` →
`/a/index.md` → `a/doc-a.md` → `a/verdict-nested.md` (reached, excluded) → `a/b/index.md`
→ `a/b/doc-b.md` → `/a/index.md` (seen, deduped) → `/overview.md` (seen, deduped).
Unreachable: `c/orphan.md`.

**Serialization** the gate compares against: the root index body verbatim, then each
**non-index** concept as `## {type}: {title}` + blank line + the file body, sections
separated by one blank line, file ending in exactly one trailing newline. The spec does
not pin whitespace beyond this shape; a gate MAY compare byte-exact or after
trailing-whitespace normalization. **Only the root index body is the summary** — nested
index bodies (`a/index.md`, `a/b/index.md`) are navigation and do not appear.