fix(explorer): complete edge label rendering

explorer/src/workspaces/GraphWorkspace/GraphCanvas.tsx

@@ -745,6 +745,12 @@ function buildEffectAvailability(
     ? { enabled: true, available: true, reason: "Panel enabled" }
     : { enabled: false, available: false, reason: "Disabled by toggle" };
 
+  // #1009: edge labels are immediately available once the graph is loaded —
+  // they have no async analytics or zoom-tier dependency.
+  const edgeLabels = effectsState.edgeLabelsEnabled
+    ? { enabled: true, available: true, reason: "Ready" }
+    : { enabled: false, available: false, reason: "Disabled by toggle" };
+
   const diagnostics = !GRAPH_THEME.effects.diagnostics.enabledInDev
     ? { enabled: false, available: false, reason: "Disabled in production" }
     : effectsState.diagnosticsEnabled
@@ -762,6 +768,7 @@ function buildEffectAvailability(
     communities,
     centrality,
     legend,
+    edgeLabels,
     diagnostics,
   };
 }
@@ -1218,7 +1225,9 @@ function applySceneState(
       // #1009: Sigma's edge label renderer draws data.label — the graph
       // stores the relationship type in edgeType, which the renderer never
       // saw, so enabling renderEdgeLabels alone left edges blank.
-      label: resolvedStyle.hidden ? undefined : String(attrs.edgeType ?? data.label ?? ""),
+      // Use || rather than ?? so that an empty-string edgeType (possible
+      // when the API returns type: "") does not produce a blank label.
+      label: resolvedStyle.hidden ? undefined : String(attrs.edgeType || data.label || ""),
     };
   });
 

explorer/src/workspaces/GraphWorkspace/graphSceneState.ts

@@ -2150,7 +2150,7 @@ function aggregateDisplayGraph(graphRef: GraphRef): Graph<NodeAttributes, EdgeAt
     const rawEdgeIds = entries.flatMap(({ edgeId, attrs }) => collectRawEdgeIds(attrs, edgeId));
     const typeCounts = new Map<string, number>();
     entries.forEach(({ attrs }) => {
-      const edgeType = String(attrs.edgeType ?? "related_to");
+      const edgeType = String(attrs.edgeType || "related_to");
       typeCounts.set(edgeType, (typeCounts.get(edgeType) ?? 0) + 1);
     });
     const dominantEdgeType = [...typeCounts.entries()].sort((left, right) => right[1] - left[1])[0]?.[0] ?? representative.attrs.edgeType ?? "related_to";
@@ -2170,7 +2170,7 @@ function aggregateDisplayGraph(graphRef: GraphRef): Graph<NodeAttributes, EdgeAt
       dominantEdgeType: String(dominantEdgeType),
       representativeWeight: Number(representative.attrs.weight ?? 1),
       weight: Number(representative.attrs.weight ?? 1),
-      edgeType: String(representative.attrs.edgeType ?? dominantEdgeType ?? "related_to"),
+      edgeType: String(representative.attrs.edgeType || dominantEdgeType || "related_to"),
       parallelCount: rawEdgeIds.length,
       familySize: rawEdgeIds.length,
       bundleKind: isBidirectionalBundle ? "bidirectional" : "parallel",
@@ -2280,7 +2280,7 @@ function buildCommunityGroupedGraph(): GraphDisplayResult {
     };
     bucket.rawEdgeIds.push(String(edgeId));
     bucket.weight = Math.max(bucket.weight, Number((attrs as EdgeAttributes).weight ?? 1));
-    const edgeType = String((attrs as EdgeAttributes).edgeType ?? "related_to");
+    const edgeType = String((attrs as EdgeAttributes).edgeType || "related_to");
     bucket.typeCounts.set(edgeType, (bucket.typeCounts.get(edgeType) ?? 0) + 1);
     groupedEdges.set(key, bucket);
   });

explorer/src/workspaces/GraphWorkspace/plugins/explorationEffectsPlugin.tsx

@@ -151,7 +151,9 @@ export const explorationEffectsPlugin: GraphPlugin = {
                         ? "pathFlow"
                         : row.key === "lensEnabled"
                           ? "lens"
-                          : "legend"
+                          : row.key === "edgeLabelsEnabled"
+                            ? "edgeLabels"
+                            : "legend"
                   ] ?? {
                     enabled: effectsState[row.key],
                     available: false,

explorer/src/workspaces/GraphWorkspace/plugins/explorationEffectsPluginPhaseC.tsx

@@ -88,7 +88,7 @@ const AVAILABILITY_KEYS: Record<GraphEffectToggle, keyof GraphDiagnosticsSnapsho
   communitiesEnabled: "communities",
   centralityEnabled: "centrality",
   legendEnabled: "legend",
-  edgeLabelsEnabled: "edge-labels",
+  edgeLabelsEnabled: "edgeLabels",
   diagnosticsEnabled: "diagnostics",
 };
 

explorer/src/workspaces/GraphWorkspace/types.ts

@@ -188,6 +188,7 @@ export interface GraphDiagnosticsSnapshot {
     communities: GraphEffectAvailability;
     centrality: GraphEffectAvailability;
     legend: GraphEffectAvailability;
+    edgeLabels: GraphEffectAvailability;
     diagnostics: GraphEffectAvailability;
   };
 }

explorer/tests/graphSceneState.display.test.ts

@@ -1061,3 +1061,155 @@ test("checkGroupedViewAvailability returns available when communities exist", ()
   assert.equal(result.reason, null);
 });
 
+
+// ── #1009: edge label data-path regression tests ─────────────────────────────
+
+test("resolveDisplayGraph parallel-bundle preserves edgeType on aggregated edge", () => {
+  addNode("a");
+  addNode("b");
+  batchMergeEdges([
+    { id: "e1", source: "a", target: "b", attributes: { edgeType: "causes", weight: 1, properties: {} } },
+    { id: "e2", source: "a", target: "b", attributes: { edgeType: "causes", weight: 2, properties: {} } },
+  ]);
+
+  const { graph: displayGraph } = resolveDisplayGraph("", [], [], "full", { aggregationEnabled: true });
+  assert.equal(displayGraph.size, 1);
+
+  const edgeId = displayGraph.edges()[0];
+  const attrs = displayGraph.getEdgeAttributes(edgeId) as { edgeType?: string; isAggregated?: boolean };
+  assert.equal(attrs.isAggregated, true);
+  // The aggregated representative must carry the relationship text through to
+  // the edgeReducer's label assignment.
+  assert.equal(typeof attrs.edgeType, "string");
+  assert.ok((attrs.edgeType ?? "").length > 0, "aggregated edge must have a non-empty edgeType");
+});
+
+test("resolveDisplayGraph parallel-bundle picks dominant edgeType across mixed types", () => {
+  addNode("a");
+  addNode("b");
+  batchMergeEdges([
+    { id: "e1", source: "a", target: "b", attributes: { edgeType: "inhibits", weight: 1, properties: {} } },
+    { id: "e2", source: "a", target: "b", attributes: { edgeType: "inhibits", weight: 1, properties: {} } },
+    { id: "e3", source: "a", target: "b", attributes: { edgeType: "activates", weight: 1, properties: {} } },
+  ]);
+
+  const { graph: displayGraph } = resolveDisplayGraph("", [], [], "full", { aggregationEnabled: true });
+  const edgeId = displayGraph.edges()[0];
+  const attrs = displayGraph.getEdgeAttributes(edgeId) as { edgeType?: string; dominantEdgeType?: string };
+  // "inhibits" appears twice so it must be the dominant type.
+  assert.equal(attrs.edgeType, "inhibits");
+  assert.equal(attrs.dominantEdgeType, "inhibits");
+});
+
+test("resolveDisplayGraph grouped view community edges carry non-empty edgeType", () => {
+  const left = ["g1", "g2", "g3", "g4"];
+  const right = ["h1", "h2", "h3", "h4"];
+  [...left, ...right].forEach((nodeId, index) => addNode(nodeId, index < left.length ? "left" : "right"));
+
+  let edgeIndex = 0;
+  for (let i = 0; i < left.length; i += 1) {
+    for (let j = 0; j < left.length; j += 1) {
+      if (i !== j) {
+        batchMergeEdges([{
+          id: `lg-${edgeIndex++}`,
+          source: left[i],
+          target: left[j],
+          attributes: { edgeType: "co_occurs", weight: 3, properties: {} },
+        }]);
+      }
+    }
+  }
+  for (let i = 0; i < right.length; i += 1) {
+    for (let j = 0; j < right.length; j += 1) {
+      if (i !== j) {
+        batchMergeEdges([{
+          id: `rg-${edgeIndex++}`,
+          source: right[i],
+          target: right[j],
+          attributes: { edgeType: "co_occurs", weight: 3, properties: {} },
+        }]);
+      }
+    }
+  }
+  batchMergeEdges([{ id: "bridge-g", source: "g1", target: "h1", attributes: { edgeType: "interacts_with", weight: 0.1, properties: {} } }]);
+
+  const { graph: displayGraph, state } = resolveDisplayGraph("", [], [], "grouped", { aggregationEnabled: true });
+  assert.equal(state.groupedViewAvailable, true);
+
+  const communityEdges = displayGraph.edges().filter((edgeId) => {
+    const attrs = displayGraph.getEdgeAttributes(edgeId) as { bundleKind?: string };
+    return attrs.bundleKind === "community";
+  });
+  assert.ok(communityEdges.length > 0, "expected at least one community bundle edge");
+
+  for (const edgeId of communityEdges) {
+    const attrs = displayGraph.getEdgeAttributes(edgeId) as { edgeType?: string };
+    assert.equal(typeof attrs.edgeType, "string");
+    assert.ok((attrs.edgeType ?? "").length > 0, `community edge ${edgeId} must have a non-empty edgeType`);
+  }
+});
+
+test("resolveDisplayGraph raw edge preserves exact edgeType string for label rendering", () => {
+  addNode("src");
+  addNode("tgt");
+  batchMergeEdges([{
+    id: "raw-1",
+    source: "src",
+    target: "tgt",
+    attributes: { edgeType: "works_for", weight: 1, properties: {} },
+  }]);
+
+  // In full view without aggregation the edge passes through unchanged.
+  const { graph: displayGraph } = resolveDisplayGraph("", [], [], "full", { aggregationEnabled: false });
+  assert.equal(displayGraph.size, 1);
+
+  const edgeId = displayGraph.edges()[0];
+  const attrs = displayGraph.getEdgeAttributes(edgeId) as { edgeType?: string };
+  assert.equal(attrs.edgeType, "works_for");
+});
+
+test("resolveDisplayGraph does not produce empty-string edgeType on aggregated edges when source has empty type", () => {
+  addNode("a");
+  addNode("b");
+  // Simulate an API response where type is empty string — the aggregation
+  // path must not propagate a blank label.
+  batchMergeEdges([
+    { id: "e-empty-1", source: "a", target: "b", attributes: { edgeType: "", weight: 1, properties: {} } },
+    { id: "e-empty-2", source: "a", target: "b", attributes: { edgeType: "", weight: 1, properties: {} } },
+  ]);
+
+  const { graph: displayGraph } = resolveDisplayGraph("", [], [], "full", { aggregationEnabled: true });
+  const edgeId = displayGraph.edges()[0];
+  const attrs = displayGraph.getEdgeAttributes(edgeId) as {
+    edgeType?: string;
+    isAggregated?: boolean;
+  };
+  assert.equal(attrs.isAggregated, true);
+  // The aggregation falls back to "related_to" when all source edgeTypes are
+  // empty, so the rendered label should never be an empty string.
+  assert.equal(attrs.edgeType, "related_to");
+});
+
+test("resolveEdgeElementStyle hidden class produces hidden:true for suppressed edges", () => {
+  // Verify the data condition the edgeReducer relies on: hidden-classified
+  // edges must have hidden:true so that the label assignment sets undefined.
+  const style = resolveEdgeElementStyle(
+    GRAPH_THEME,
+    "overview",
+    "inactive",
+    {
+      edgeType: "causes",
+      weight: 1,
+      properties: {},
+      edgeVariant: "line",
+      visualPriority: 0.05,
+      baseSize: 0.3,
+    },
+    "source",
+    "target",
+    "full",
+    "inactive-edge",
+    "hidden",
+  );
+  assert.equal(style.hidden, true);
+});