refactor(log): extract shared displayTraceLogs helper (#329)

Extract duplicated trace-log display logic into a shared
displayTraceLogs() function in src/lib/formatters/log.ts.

Both 'sentry log list --trace' and 'sentry trace logs' now use
the same helper for JSON output, empty state, and table formatting.

This also normalizes JSON output for trace/logs.ts to use
chronological order (oldest-first), consistent with all other
JSON outputs in the CLI.

Author: BYK

AGENTS.md

@@ -677,7 +677,7 @@ mock.module("./some-module", () => ({
 * **PR review workflow: reply, resolve, amend, force-push**: PR review workflow: (1) Read unresolved threads via GraphQL, (2) make code changes, (3) run lint+typecheck+tests, (4) create a SEPARATE commit per review round (not amend) for incremental review, (5) push normally, (6) reply to comments via REST API, (7) resolve threads via GraphQL \`resolveReviewThread\`. Only amend+force-push when user explicitly asks or pre-commit hook modified files.
 
 <!-- lore:019cb858-e780-7945-a0ee-a01f85be5585 -->
-* **Testing infinite loops (while-true) in streaming functions via AuthError escape hatch**: Follow-mode streaming in \`sentry log list\` uses \`setTimeout\`-based recursive scheduling. \`scheduleNextPoll()\` sets a timer; SIGINT handler calls \`clearTimeout()\` + \`resolve()\`. No \`process.exit(0)\` needed — clearing the timer drains the event loop naturally. A \`stopped\` boolean guard prevents orphaned poll loops when SIGINT fires during an in-flight fetch. Both \`scheduleNextPoll()\` and \`poll()\` check \`stopped\` before doing work. \`Bun.sleep()\` cannot be cancelled (no AbortSignal support), so \`setTimeout\`/\`clearTimeout\` is required. The Promise constructor uses an async IIFE for the initial fetch (async/await inside \`new Promise\` with external \`resolve\`/\`reject\` for SIGINT). Tests use \`interceptSigint()\` helper that captures \`process.once('SIGINT', handler)\` via spy, then \`trigger()\` invokes it directly. \`executeFollowMode\<T>(config: FollowConfig\<T>)\` is generic — parameterized by a single \`fetch(statsPeriod, afterTimestamp?)\` callback plus \`extractNew\`.
+* **Testing infinite loops (while-true) in streaming functions via AuthError escape hatch**: Follow-mode streaming in \`sentry log list\` uses \`setTimeout\`-based recursive scheduling. \`scheduleNextPoll()\` sets a timer; SIGINT handler calls \`clearTimeout()\` + \`resolve()\`. No \`process.exit(0)\` needed — clearing the timer drains the event loop naturally. A \`stopped\` boolean guard prevents orphaned poll loops when SIGINT fires during an in-flight fetch. Both \`scheduleNextPoll()\` and \`poll()\` check \`stopped\` before doing work. \`Bun.sleep()\` cannot be cancelled (no AbortSignal support), so \`setTimeout\`/\`clearTimeout\` is required. The Promise constructor uses fire-and-forget \`.then()/.catch()\` for the initial fetch — cannot use async IIFE because \`resolve\` must remain callable by the SIGINT handler (\`stop\`) at any time; awaiting would block the executor. Tests use \`interceptSigint()\` helper that captures \`process.once('SIGINT', handler)\` via spy, then \`trigger()\` invokes it directly. \`executeFollowMode\<T>(config: FollowConfig\<T>)\` is generic — parameterized by a single \`fetch(statsPeriod, afterTimestamp?)\` callback plus \`extractNew\`.
 
 ### Preference
 

src/commands/log/list.ts

@@ -15,6 +15,7 @@ import { AuthError, ContextError, stringifyUnknown } from "../../lib/errors.js";
 import {
   buildLogRowCells,
   createLogStreamingTable,
+  displayTraceLogs,
   formatLogRow,
   formatLogsHeader,
   formatLogTable,
@@ -341,26 +342,16 @@ async function executeTraceSingleFetch(
     statsPeriod: DEFAULT_TRACE_PERIOD,
   });
 
-  if (flags.json) {
-    writeJson(stdout, [...logs].reverse());
-    return;
-  }
-
-  if (logs.length === 0) {
-    stdout.write(
+  displayTraceLogs({
+    stdout,
+    logs,
+    traceId,
+    limit: flags.limit,
+    asJson: flags.json,
+    emptyMessage:
       `No logs found for trace ${traceId} in the last ${DEFAULT_TRACE_PERIOD}.\n\n` +
-        "Try 'sentry trace logs' for more options (e.g., --period 30d).\n"
-    );
-    return;
-  }
-
-  const chronological = [...logs].reverse();
-  stdout.write(formatLogTable(chronological, false));
-
-  const hasMore = logs.length >= flags.limit;
-  const countText = `Showing ${logs.length} log${logs.length === 1 ? "" : "s"} for trace ${traceId}.`;
-  const tip = hasMore ? " Use --limit to show more." : "";
-  writeFooter(stdout, `${countText}${tip}`);
+      "Try 'sentry trace logs' for more options (e.g., --period 30d).\n",
+  });
 }
 
 export const listCommand = buildListCommand("log", {

src/commands/trace/logs.ts

@@ -10,11 +10,7 @@ import { validateLimit } from "../../lib/arg-parsing.js";
 import { openInBrowser } from "../../lib/browser.js";
 import { buildCommand } from "../../lib/command.js";
 import { ContextError } from "../../lib/errors.js";
-import {
-  formatLogTable,
-  writeFooter,
-  writeJson,
-} from "../../lib/formatters/index.js";
+import { displayTraceLogs } from "../../lib/formatters/index.js";
 import { resolveOrg } from "../../lib/resolve-target.js";
 import { buildTraceUrl } from "../../lib/sentry-urls.js";
 import { validateTraceId } from "../../lib/trace-id.js";
@@ -205,27 +201,15 @@ export const logsCommand = buildCommand({
       query: flags.query,
     });
 
-    if (flags.json) {
-      writeJson(stdout, logs);
-      return;
-    }
-
-    if (logs.length === 0) {
-      stdout.write(
+    displayTraceLogs({
+      stdout,
+      logs,
+      traceId,
+      limit: flags.limit,
+      asJson: flags.json,
+      emptyMessage:
         `No logs found for trace ${traceId} in the last ${flags.period}.\n\n` +
-          `Try a longer period: sentry trace logs --period 30d ${traceId}\n`
-      );
-      return;
-    }
-
-    // API returns newest-first; reverse for chronological display
-    const chronological = [...logs].reverse();
-
-    stdout.write(formatLogTable(chronological, false));
-
-    const hasMore = logs.length >= flags.limit;
-    const countText = `Showing ${logs.length} log${logs.length === 1 ? "" : "s"} for trace ${traceId}.`;
-    const tip = hasMore ? " Use --limit to show more." : "";
-    writeFooter(stdout, `${countText}${tip}`);
+        `Try a longer period: sentry trace logs --period 30d ${traceId}\n`,
+    });
   },
 });

src/lib/formatters/log.ts

@@ -4,8 +4,13 @@
  * Provides formatting utilities for displaying Sentry logs in the CLI.
  */
 
-import type { DetailedSentryLog, SentryLog } from "../../types/index.js";
+import type {
+  DetailedSentryLog,
+  SentryLog,
+  Writer,
+} from "../../types/index.js";
 import { buildTraceUrl } from "../sentry-urls.js";
+import { writeJson } from "./json.js";
 import {
   colorTag,
   escapeMarkdownCell,
@@ -18,6 +23,7 @@ import {
   renderMarkdown,
   stripColorTags,
 } from "./markdown.js";
+import { writeFooter } from "./output.js";
 import {
   renderTextTable,
   StreamingTable,
@@ -317,3 +323,49 @@ export function formatLogDetails(
 
   return renderMarkdown(lines.join("\n"));
 }
+
+/**
+ * Options for {@link displayTraceLogs}.
+ */
+type DisplayTraceLogsOptions = {
+  /** Writer for output */
+  stdout: Writer;
+  /** Already-fetched logs (API order: newest-first) */
+  logs: LogLike[];
+  /** The trace ID being queried */
+  traceId: string;
+  /** The --limit value (used for "has more" hint) */
+  limit: number;
+  /** Output as JSON instead of human-readable table */
+  asJson: boolean;
+  /** Message to show when no logs are found */
+  emptyMessage: string;
+};
+
+/**
+ * Shared display logic for trace-filtered log results.
+ *
+ * Handles JSON output, empty state, and human-readable table formatting.
+ * Used by both `sentry log list --trace` and `sentry trace logs`.
+ */
+export function displayTraceLogs(options: DisplayTraceLogsOptions): void {
+  const { stdout, logs, traceId, limit, asJson, emptyMessage } = options;
+
+  if (asJson) {
+    writeJson(stdout, [...logs].reverse());
+    return;
+  }
+
+  if (logs.length === 0) {
+    stdout.write(emptyMessage);
+    return;
+  }
+
+  const chronological = [...logs].reverse();
+  stdout.write(formatLogTable(chronological, false));
+
+  const hasMore = logs.length >= limit;
+  const countText = `Showing ${logs.length} log${logs.length === 1 ? "" : "s"} for trace ${traceId}.`;
+  const tip = hasMore ? " Use --limit to show more." : "";
+  writeFooter(stdout, `${countText}${tip}`);
+}

test/commands/trace/logs.test.ts

@@ -230,7 +230,8 @@ describe("logsCommand.func", () => {
       const parsed = JSON.parse(output);
       expect(Array.isArray(parsed)).toBe(true);
       expect(parsed).toHaveLength(3);
-      expect(parsed[0].id).toBe("log001");
+      // displayTraceLogs reverses to chronological order for JSON output
+      expect(parsed[0].id).toBe("log003");
     });
 
     test("outputs empty JSON array when no logs found with --json", async () => {