bug: graph emits zero edges and an empty Mermaid diagram when import relationships exist only among primary-ranked files

[aryamthecodebreaker]

Summary

fixmap graph promises to "Export imports, reverse dependents, routed tests, and co-change evidence as Mermaid or JSON". For repositories whose import relationships exist only among primary-ranked files — typically repos without test files, i.e. exactly where agents most need dependency hints — it emits zero edges: "edges": [] in JSON and a bare two-classDef Mermaid diagram with no nodes' relationships drawn.

Meanwhile fixmap plan on the same repo explicitly reports those import relationships in its Context Files reasons ("imported by ranked file src/x.js", "imports ranked file src/a.js", "within two import hops"), so the evidence exists and is discarded at export time.

Environment

• fixmap 0.9.0 (npm global)
• Windows (win32), Node v24.13.0

Repro 1 — linear chain, no tests

git init demo && cd demo
Set-Content package.json '{"name":"demo","scripts":{"test":"node --test"}}'
New-Item src | Out-Null
Set-Content src\x.js 'import { y } from "./y.js"; export function loginX(){ return y(); }'
Set-Content src\y.js 'import { z } from "./z.js"; export function y(){ return z(); }'
Set-Content src\z.js 'export function z(){ return 3; }'
git add -A; git commit -m init

fixmap plan --issue "loginX broken"
#   src/y.js ... imported by ranked file src/x.js      <- relationship computed
#   src/z.js ... within two import hops of ranked file src/x.js
#   Impact Graph: None found

fixmap graph --issue "loginX broken" --format json

Actual JSON:

{
  "graphVersion": 1,
  "nodes": [
    { "id": "n1", "path": "src/x.js", "role": "primary", ... },
    { "id": "n2", "path": "src/y.js", "role": "primary", ... },
    { "id": "n3", "path": "src/z.js", "role": "primary", ... }
  ],
  "edges": []
}

Mermaid output is an empty flowchart TD with three nodes and no edges.

Repro 2 — import cycle

Same shape with a.js → b.js → c.js → a.js plus a self-import and an import of a missing file: plan reports "src/c.js … imports ranked file src/a.js" and "src/b.js … imported by ranked file src/a.js", while graph again returns "edges": []. Cycles do not crash anything; the edges simply never appear.

Control case

Adding one test file (test/x.test.js importing ../src/x.js) makes the test land in the Impact Graph, and then its edge is emitted (kind: "imported-by"). So edge emission works only for impact-role endpoints; plain import / reverse-dependent relations between primary-ranked files are never exported.

Expected

Either:

1. Import edges between primary-ranked files are emitted (the plan already computes and prints them), or
2. The report says why no relationships were exported (e.g. a diagnostic like "no impact-role relationships; import edges among context files are not exported"), because right now an all-primary repo silently gets a relationship-free graph that contradicts both the docs and the plan text produced seconds earlier.

The silent empty output matters downstream: consumers (the /fixmap agent flow, the MCP fixmap_graph tool) read "edges": [] as "this code has no relevant dependents", which is false for every chained/cyclic module layout.