Preserve zero relevance threshold in settings

Author: chengtan9907

deployments/desktop/static/desktop.js

@@ -2223,7 +2223,9 @@
     parts.push(ui().papers.recommendations(papers.length));
     if (metadata.daily_limit) parts.push(ui().papers.dailyLimit(metadata.daily_limit));
     if (metadata.limit_per_source) parts.push(ui().papers.perSourceLimit(metadata.limit_per_source));
-    if (metadata.relevance_threshold) parts.push(ui().papers.threshold(metadata.relevance_threshold));
+    if (metadata.relevance_threshold !== undefined && metadata.relevance_threshold !== null && metadata.relevance_threshold !== "") {
+      parts.push(ui().papers.threshold(metadata.relevance_threshold));
+    }
     const sourceParts = [
       metadata.arxiv_categories?.length ? `arXiv ${metadata.arxiv_categories.length}` : "",
       metadata.conferences?.length ? ui().papers.conferenceCount(metadata.conferences.length) : "",
@@ -5274,8 +5276,8 @@
     $("directPdfWriteFeishu").checked = Boolean(reportPrefs.write_feishu);
     $("wikiIngestSetting").checked = reportPrefs.wiki_ingest !== false;
     if ($("notesGitLlmReviewSetting")) $("notesGitLlmReviewSetting").checked = paths.reading_notes_git_llm_review !== false;
-    $("dailyLimitInput").value = advanced.daily_limit || 30;
-    $("relevanceThreshold").value = advanced.relevance_threshold || 60;
+    $("dailyLimitInput").value = advanced.daily_limit ?? 30;
+    $("relevanceThreshold").value = advanced.relevance_threshold ?? 60;
     $("relevanceValue").textContent = $("relevanceThreshold").value;
     $("proxyInput").value = advanced.http_proxy || "";
     $("envSettingsForm").className = "env-form";

tests/test_desktop_gui.py

@@ -1289,6 +1289,25 @@ def test_desktop_save_settings_updates_env_file(tmp_path, monkeypatch: pytest.Mo
     assert result["source_preferences"]["auth_status"]["semantic_scholar_api_key"] is True
 
 
+def test_desktop_settings_preserves_zero_relevance_threshold(tmp_path, monkeypatch: pytest.MonkeyPatch) -> None:
+    env_path = tmp_path / ".env"
+    env_path.write_text("PAPERFLOW_RELEVANCE_THRESHOLD=60\n", encoding="utf-8")
+    monkeypatch.setattr(agents, "ENV_PATH", env_path)
+
+    result = agents.save_settings({"PAPERFLOW_RELEVANCE_THRESHOLD": "0"})
+
+    assert "PAPERFLOW_RELEVANCE_THRESHOLD=0" in env_path.read_text(encoding="utf-8")
+    assert result["advanced"]["relevance_threshold"] == 0
+
+
+def test_desktop_settings_ui_does_not_fallback_zero_relevance_threshold() -> None:
+    script = (PROJECT_ROOT / "deployments/desktop/static/desktop.js").read_text(encoding="utf-8")
+
+    assert "$(\"relevanceThreshold\").value = advanced.relevance_threshold ?? 60;" in script
+    assert "$(\"relevanceThreshold\").value = advanced.relevance_threshold || 60;" not in script
+    assert "metadata.relevance_threshold !== undefined" in script
+
+
 def test_desktop_github_sync_commits_notes_with_llm_review(tmp_path, monkeypatch: pytest.MonkeyPatch) -> None:
     bare = tmp_path / "notes.git"
     seed = tmp_path / "seed"