refactor(transformer): rename short variable names to descriptive identifiers

Replace resp/cand/p/b with responseRecord/candidateRecord/partRecord/blockRecord
for clarity. Add unit tests covering the renamed code paths.

Co-Authored-By: Giulio Vaccari <io@giuliovaccari.it>

src/plugin/core/streaming/transformer.test.ts

@@ -0,0 +1,136 @@
+import { describe, expect, it, vi } from "vitest";
+import {
+  transformStreamingPayload,
+  deduplicateThinkingText,
+  cacheThinkingSignaturesFromResponse,
+  createThoughtBuffer,
+} from "./transformer";
+import { createSignatureStore } from "../../stores/signature-store";
+
+// ─── Helpers ──────────────────────────────────────────────────────────────────
+
+function geminiResponse(parts: unknown[]) {
+  return { candidates: [{ content: { role: "model", parts } }] };
+}
+
+function thinkingPart(text: string) {
+  return { thought: true, text };
+}
+
+function textPart(text: string) {
+  return { text };
+}
+
+// ─── transformStreamingPayload ────────────────────────────────────────────────
+
+describe("transformStreamingPayload", () => {
+  it("passes non-data lines through unchanged", () => {
+    const line = "event: message";
+    expect(transformStreamingPayload(line)).toBe(line);
+  });
+
+  it("passes empty data line unchanged", () => {
+    expect(transformStreamingPayload("data: ")).toBe("data: ");
+  });
+
+  it("passes invalid JSON data line unchanged", () => {
+    expect(transformStreamingPayload("data: {not json}")).toBe("data: {not json}");
+  });
+
+  it("passes data without response field unchanged", () => {
+    const line = `data: ${JSON.stringify({ candidates: [] })}`;
+    expect(transformStreamingPayload(line)).toBe(line);
+  });
+
+  it("applies transformThinkingParts to response field", () => {
+    const inner = { type: "thinking", text: "reasoning" };
+    const payload = { response: inner };
+    const transform = vi.fn().mockReturnValue({ type: "redacted_thinking" });
+    const result = transformStreamingPayload(`data: ${JSON.stringify(payload)}`, transform);
+    expect(transform).toHaveBeenCalledWith(inner);
+    expect(result).toContain("redacted_thinking");
+  });
+});
+
+// ─── deduplicateThinkingText — Gemini candidates ──────────────────────────────
+
+describe("deduplicateThinkingText", () => {
+  it("returns null input unchanged", () => {
+    expect(deduplicateThinkingText(null, createThoughtBuffer())).toBeNull();
+  });
+
+  it("passes non-thinking parts through", () => {
+    const buf = createThoughtBuffer();
+    const resp = geminiResponse([textPart("hello")]);
+    const result = deduplicateThinkingText(resp, buf) as typeof resp;
+    expect(result.candidates[0].content.parts).toEqual([textPart("hello")]);
+  });
+
+  it("emits full thinking text on first call", () => {
+    const buf = createThoughtBuffer();
+    const result = deduplicateThinkingText(geminiResponse([thinkingPart("hello")]), buf) as any;
+    expect(result.candidates[0].content.parts[0].text).toBe("hello");
+  });
+
+  it("emits only the new delta on subsequent call with extended text", () => {
+    const buf = createThoughtBuffer();
+    deduplicateThinkingText(geminiResponse([thinkingPart("alpha")]), buf);
+    const result = deduplicateThinkingText(geminiResponse([thinkingPart("alphabeta")]), buf) as any;
+    expect(result.candidates[0].content.parts[0].text).toBe("beta");
+  });
+
+  it("filters out duplicate thinking when hash set is provided", () => {
+    const buf = createThoughtBuffer();
+    const seen = new Set<string>();
+    const resp = geminiResponse([thinkingPart("same")]);
+    deduplicateThinkingText(resp, buf, seen);
+    const result2 = deduplicateThinkingText(resp, buf, seen) as any;
+    const parts = result2.candidates[0].content.parts;
+    expect(parts.some((p: any) => p.thought === true)).toBe(false);
+  });
+});
+
+// ─── cacheThinkingSignaturesFromResponse ──────────────────────────────────────
+
+describe("cacheThinkingSignaturesFromResponse", () => {
+  it("accumulates thinking text in the thought buffer", () => {
+    const store = createSignatureStore();
+    const buf = createThoughtBuffer();
+    cacheThinkingSignaturesFromResponse(geminiResponse([thinkingPart("my thoughts")]), "k", store, buf);
+    expect(buf.get(0)).toBe("my thoughts");
+  });
+
+  it("fires onCacheSignature with session key, text, and signature", () => {
+    const store = createSignatureStore();
+    const buf = createThoughtBuffer();
+    const onSig = vi.fn();
+    cacheThinkingSignaturesFromResponse(
+      geminiResponse([thinkingPart("reasoning"), { thoughtSignature: "sig-1" }]),
+      "sess",
+      store,
+      buf,
+      onSig,
+    );
+    expect(onSig).toHaveBeenCalledWith("sess", "reasoning", "sig-1");
+  });
+
+  it("stores result in signatureStore keyed by session key", () => {
+    const store = createSignatureStore();
+    const buf = createThoughtBuffer();
+    cacheThinkingSignaturesFromResponse(
+      geminiResponse([thinkingPart("t"), { thoughtSignature: "sig-2" }]),
+      "session-a",
+      store,
+      buf,
+    );
+    expect(store.get("session-a")).toEqual({ text: "t", signature: "sig-2" });
+  });
+
+  it("skips firing onCacheSignature when no thinking text was accumulated", () => {
+    const store = createSignatureStore();
+    const buf = createThoughtBuffer();
+    const onSig = vi.fn();
+    cacheThinkingSignaturesFromResponse(geminiResponse([{ thoughtSignature: "sig" }]), "k", store, buf, onSig);
+    expect(onSig).not.toHaveBeenCalled();
+  });
+});

src/plugin/core/streaming/transformer.ts

@@ -62,22 +62,22 @@ export function deduplicateThinkingText(
 ): unknown {
   if (!response || typeof response !== 'object') return response;
 
-  const resp = response as Record<string, unknown>;
+  const responseRecord = response as Record<string, unknown>;
 
-  if (Array.isArray(resp.candidates)) {
-    const newCandidates = resp.candidates.map((candidate: unknown, index: number) => {
-      const cand = candidate as Record<string, unknown> | null;
-      if (!cand?.content) return candidate;
+  if (Array.isArray(responseRecord.candidates)) {
+    const newCandidates = responseRecord.candidates.map((candidate: unknown, index: number) => {
+      const candidateRecord = candidate as Record<string, unknown> | null;
+      if (!candidateRecord?.content) return candidate;
 
-      const content = cand.content as Record<string, unknown>;
+      const content = candidateRecord.content as Record<string, unknown>;
       if (!Array.isArray(content.parts)) return candidate;
 
       const newParts = content.parts.map((part: unknown) => {
-        const p = part as Record<string, unknown>;
-        
+        const partRecord = part as Record<string, unknown>;
+
         // Handle image data - save to disk and return file path
-        if (p.inlineData) {
-          const inlineData = p.inlineData as Record<string, unknown>;
+        if (partRecord.inlineData) {
+          const inlineData = partRecord.inlineData as Record<string, unknown>;
           const result = processImageData({
             mimeType: inlineData.mimeType as string | undefined,
             data: inlineData.data as string | undefined,
@@ -86,10 +86,10 @@ export function deduplicateThinkingText(
             return { text: result };
           }
         }
-        
-        if (p.thought === true || p.type === 'thinking') {
-          const fullText = (p.text || p.thinking || '') as string;
-          
+
+        if (partRecord.thought === true || partRecord.type === 'thinking') {
+          const fullText = (partRecord.text || partRecord.thinking || '') as string;
+
           if (displayedThinkingHashes) {
             const hash = hashString(fullText);
             if (displayedThinkingHashes.has(hash)) {
@@ -106,7 +106,7 @@ export function deduplicateThinkingText(
             sentBuffer.set(index, fullText);
 
             if (delta) {
-              return { ...p, text: delta, thinking: delta };
+              return { ...partRecord, text: delta, thinking: delta };
             }
             return null;
           }
@@ -117,24 +117,24 @@ export function deduplicateThinkingText(
         return part;
       });
 
-      const filteredParts = newParts.filter((p) => p !== null);
+      const filteredParts = newParts.filter((item) => item !== null);
 
       return {
-        ...cand,
+        ...candidateRecord,
         content: { ...content, parts: filteredParts },
       };
     });
 
-    return { ...resp, candidates: newCandidates };
+    return { ...responseRecord, candidates: newCandidates };
   }
 
-  if (Array.isArray(resp.content)) {
+  if (Array.isArray(responseRecord.content)) {
     let thinkingIndex = 0;
-    const newContent = resp.content.map((block: unknown) => {
-      const b = block as Record<string, unknown> | null;
-      if (b?.type === 'thinking') {
-        const fullText = (b.thinking || b.text || '') as string;
-        
+    const newContent = responseRecord.content.map((block: unknown) => {
+      const blockRecord = block as Record<string, unknown> | null;
+      if (blockRecord?.type === 'thinking') {
+        const fullText = (blockRecord.thinking || blockRecord.text || '') as string;
+
         if (displayedThinkingHashes) {
           const hash = hashString(fullText);
           if (displayedThinkingHashes.has(hash)) {
@@ -153,7 +153,7 @@ export function deduplicateThinkingText(
           thinkingIndex++;
 
           if (delta) {
-            return { ...b, thinking: delta, text: delta };
+            return { ...blockRecord, thinking: delta, text: delta };
           }
           return null;
         }
@@ -165,8 +165,8 @@ export function deduplicateThinkingText(
       return block;
     });
 
-    const filteredContent = newContent.filter((b) => b !== null);
-    return { ...resp, content: filteredContent };
+    const filteredContent = newContent.filter((item) => item !== null);
+    return { ...responseRecord, content: filteredContent };
   }
 
   return response;
@@ -232,29 +232,29 @@ export function cacheThinkingSignaturesFromResponse(
 ): void {
   if (!response || typeof response !== 'object') return;
 
-  const resp = response as Record<string, unknown>;
+  const responseRecord = response as Record<string, unknown>;
 
-  if (Array.isArray(resp.candidates)) {
-    resp.candidates.forEach((candidate: unknown, index: number) => {
-      const cand = candidate as Record<string, unknown> | null;
-      if (!cand?.content) return;
-      const content = cand.content as Record<string, unknown>;
+  if (Array.isArray(responseRecord.candidates)) {
+    responseRecord.candidates.forEach((candidate: unknown, index: number) => {
+      const candidateRecord = candidate as Record<string, unknown> | null;
+      if (!candidateRecord?.content) return;
+      const content = candidateRecord.content as Record<string, unknown>;
       if (!Array.isArray(content.parts)) return;
 
       content.parts.forEach((part: unknown) => {
-        const p = part as Record<string, unknown>;
-        if (p.thought === true || p.type === 'thinking') {
-          const text = (p.text || p.thinking || '') as string;
+        const partRecord = part as Record<string, unknown>;
+        if (partRecord.thought === true || partRecord.type === 'thinking') {
+          const text = (partRecord.text || partRecord.thinking || '') as string;
           if (text) {
             const current = thoughtBuffer.get(index) ?? '';
             thoughtBuffer.set(index, current + text);
           }
         }
 
-        if (p.thoughtSignature) {
+        if (partRecord.thoughtSignature) {
           const fullText = thoughtBuffer.get(index) ?? '';
           if (fullText) {
-            const signature = p.thoughtSignature as string;
+            const signature = partRecord.thoughtSignature as string;
             onCacheSignature?.(signatureSessionKey, fullText, signature);
             signatureStore.set(signatureSessionKey, { text: fullText, signature });
           }
@@ -263,23 +263,23 @@ export function cacheThinkingSignaturesFromResponse(
     });
   }
 
-  if (Array.isArray(resp.content)) {
+  if (Array.isArray(responseRecord.content)) {
     // Use thoughtBuffer to accumulate thinking text across SSE events
     // Claude streams thinking content and signature in separate events
     const CLAUDE_BUFFER_KEY = 0; // Use index 0 for Claude's single-stream content
-    resp.content.forEach((block: unknown) => {
-      const b = block as Record<string, unknown> | null;
-      if (b?.type === 'thinking') {
-        const text = (b.thinking || b.text || '') as string;
+    responseRecord.content.forEach((block: unknown) => {
+      const blockRecord = block as Record<string, unknown> | null;
+      if (blockRecord?.type === 'thinking') {
+        const text = (blockRecord.thinking || blockRecord.text || '') as string;
         if (text) {
           const current = thoughtBuffer.get(CLAUDE_BUFFER_KEY) ?? '';
           thoughtBuffer.set(CLAUDE_BUFFER_KEY, current + text);
         }
       }
-      if (b?.signature) {
+      if (blockRecord?.signature) {
         const fullText = thoughtBuffer.get(CLAUDE_BUFFER_KEY) ?? '';
         if (fullText) {
-          const signature = b.signature as string;
+          const signature = blockRecord.signature as string;
           onCacheSignature?.(signatureSessionKey, fullText, signature);
           signatureStore.set(signatureSessionKey, { text: fullText, signature });
         }