Use Barrett instructor listings before OSU publishes them

README.md

@@ -102,6 +102,12 @@ The Ohio State address in that picture does not. It sends one header,
 `Access-Control-Allow-Origin: *`, which is standing permission for any page
 to read it. That header is why Finder can exist with no server.
 
+Barrett's file also carries a compact instructor listing, and it can land
+there before the primary instructor appears in Ohio State's class API. The
+nightly snapshot keeps that fourth field beside the seat counts. Finder uses
+it only when the live response has no primary instructor and gives the live
+Ohio State assignment precedence as soon as it appears.
+
 ### OSU's API reports enrollment wrong per section
 
 OSU's class API returns one enrollment number per course and stamps it onto

data/seats.json

@@ -1 +1 @@
-{"source":"https://www.asc.ohio-state.edu/barrett.3/schedule/","fields":["enrolled","limit","waitlist"],"note":"Barrett rebuilds a live term once a day around 06:50 Eastern and freezes a term once it is over, so sourceUpdated differs per term. A missing class number means unknown, not zero.","terms":[{"term":"1264","termName":"Summer 2026","sourceUpdated":"2026-07-29","sections":4866,"file":"seats-1264.json"},{"term":"1268","termName":"Autumn 2026","sourceUpdated":"2026-09-16","sections":17753,"file":"seats-1268.json"},{"term":"1272","termName":"Spring 2027","sourceUpdated":"2026-09-16","sections":16579,"file":"seats-1272.json"}]}
+{"source":"https://www.asc.ohio-state.edu/barrett.3/schedule/","fields":["enrolled","limit","waitlist","instructor"],"note":"Barrett rebuilds a live term once a day around 06:50 Eastern and freezes a term once it is over, so sourceUpdated differs per term. Instructor is Barrett's compact listing and is used only when Ohio State has not published a primary instructor. A missing class number means unknown, not zero.","terms":[{"term":"1264","termName":"Summer 2026","sourceUpdated":"2026-07-29","sections":4866,"file":"seats-1264.json"},{"term":"1268","termName":"Autumn 2026","sourceUpdated":"2026-09-16","sections":17753,"file":"seats-1268.json"},{"term":"1272","termName":"Spring 2027","sourceUpdated":"2026-09-16","sections":16579,"file":"seats-1272.json"}]}

js/app.js

@@ -3,7 +3,7 @@ import { filterCourses, parseQuery } from "./rank.js";
 import { renderResults } from "./render.js";
 import { loadRatings, loadRatingCourses, topRated, ratedCount, profileUrl, ratingsFailed } from "./ratings.js";
 import { loadGrades } from "./grades.js";
-import { linkedTo, loadSeats, seatsTerm, seatsUpdated, seatsSectionCount, seatsFailed } from "./seats.js";
+import { linkedTo, loadSeats, seatsTerm, seatsUpdated, seatsSectionCount, seatsFailed, withSeatInstructors } from "./seats.js";
 import { loadTrend } from "./trend.js";
 import { renderDetail } from "./detail.js";
 import { loadHeadshots } from "./headshots.js";
@@ -840,7 +840,10 @@ async function runSearch(q, term, subject, gen = genCategory()) {
       loadTrend(term),
     ]);
     if (requestId !== latestRequest) return; // a newer search already answered
-    lastResult = { ...filterCourses(courses, q), totalItems, term };
+    // Barrett's nightly file can name an instructor before the live class API
+    // does. It is already awaited above for seats, so applying the fallback
+    // adds no request to a course search.
+    lastResult = { ...filterCourses(withSeatInstructors(courses, term), q), totalItems, term };
     lastQuery = q.trim();
     paint(term);
   } catch (error) {

js/format.js

@@ -107,10 +107,18 @@ export function trendLabel(trend) {
 /** Instructors for a section, deduped, since they hang off each meeting. */
 export function instructorsOf(section) {
   const seen = new Map();
-  for (const meeting of section?.meetings ?? []) {
-    for (const person of meeting?.instructors ?? []) {
+  const groups = [
+    ...(section?.meetings ?? []).map((meeting) => meeting?.instructors ?? []),
+    section?.fallbackInstructors ?? [],
+  ];
+  for (const people of groups) {
+    for (const person of people) {
       const name = person?.displayName?.trim();
-      if (name && !seen.has(name)) seen.set(name, { name, email: person.email ?? null, role: person.role ?? null });
+      if (name && !seen.has(name)) {
+        const found = { name, email: person.email ?? null, role: person.role ?? null };
+        if (person.source) found.source = person.source;
+        seen.set(name, found);
+      }
     }
   }
   return [...seen.values()];

js/seats.js

@@ -162,6 +162,62 @@ export function seatsFor(classNumber, term) {
   };
 }
 
+/**
+ * The instructor listing Barrett publishes for one section, or an empty list.
+ *
+ * Barrett writes compact names such as `P.Bucci` and can list several with a
+ * comma. A parenthesized suffix is its role: TA and graduate assistants are
+ * not promoted to primary instructors. Old snapshots have only three fields,
+ * so this naturally reads as absent until the nightly refresh writes the new
+ * column.
+ */
+export function instructorsFor(classNumber, term) {
+  if (!term) return [];
+  const raw = loaded.get(String(term))?.sections?.[String(classNumber)]?.[3];
+  if (typeof raw !== "string" || !raw.trim()) return [];
+
+  return raw.split(/,\s+/).map((listing) => {
+    const match = /^(.+?)(?:\s+\(([^)]+)\))?$/.exec(listing.trim());
+    const compact = match?.[1]?.trim() ?? "";
+    if (!compact) return null;
+    const dot = compact.indexOf(".");
+    const name = dot > 0 ? `${compact.slice(0, dot + 1)} ${compact.slice(dot + 1)}` : compact;
+    const code = match?.[2]?.trim().toUpperCase() ?? "";
+    return {
+      displayName: name,
+      email: null,
+      // An unqualified name is the primary listing. Preserve every explicit
+      // Barrett role (TA, SI, GR, GY, LA, GS...) so none is accidentally
+      // promoted merely because a new code appeared upstream.
+      role: code || "PI",
+      source: "barrett",
+    };
+  }).filter(Boolean);
+}
+
+/**
+ * Add Barrett's earlier instructor assignment to sections for which Ohio
+ * State has not published a primary instructor yet. The fallback lives on the
+ * section instead of being spliced into a fake meeting, so it cannot invent a
+ * time or room. Returns new entries and sections; the API response stays
+ * untouched for cached searches and tests.
+ */
+export function withSeatInstructors(entries, term) {
+  return (entries ?? []).map((entry) => ({
+    ...entry,
+    sections: (entry.sections ?? []).map((section) => {
+      const apiPeople = (section.meetings ?? []).flatMap((meeting) => meeting?.instructors ?? []);
+      if (apiPeople.some((person) => person?.role === "PI")) return section;
+      // This feature fills the professor assignment. Barrett also names TAs
+      // and graduate assistants, but adding those beside an API-published TA
+      // can duplicate the same person in compact and full-name forms.
+      const fallbackInstructors = instructorsFor(section.classNumber, term)
+        .filter((person) => person.role === "PI");
+      return fallbackInstructors.length ? { ...section, fallbackInstructors } : section;
+    }),
+  }));
+}
+
 // Both directions of a term's packages, built once per term. The snapshot
 // stores each one parent first, which is where the direction lives. A section
 // can sit under two parents, so the child side is a list.

scripts/fetch-seats.mjs

@@ -213,6 +213,17 @@ function parseDays(line) {
   return out;
 }
 
+// The area after column 94 usually holds instructors, but short-session rows
+// use it for markers such as {7W1}. Every instructor token Barrett publishes
+// starts with an initial and a dot; require that shape for every comma-separated
+// person so a session marker can never become a professor on screen.
+function instructorListing(raw) {
+  const value = raw.trim();
+  if (!value) return '';
+  const people = value.split(/,\s+/);
+  return people.every((person) => /^[A-Za-z][A-Za-z'-]*\.[^\s].*/.test(person)) ? value : '';
+}
+
 // A file whose shape is not the one the column map describes is a layout
 // change, not a stray line, so a caller that tolerates a few bad subjects has
 // to rethrow this rather than count it as one of them.
@@ -271,7 +282,7 @@ function parseSubjectFile(subject, term, text) {
       enrolled: Number(tail[2]),
       limit: Number(tail[3]),
       waitlist: tail[4] ? Number(tail[4]) : 0,
-      instructor: line.slice(INSTRUCTOR_START).trim(),
+      instructor: instructorListing(line.slice(INSTRUCTOR_START)),
     });
   }
 
@@ -401,7 +412,13 @@ async function snapshotTerm(term, subjects) {
   const sections = {};
   for (const key of [...byClass.keys()].sort((a, b) => Number(a) - Number(b))) {
     const s = byClass.get(key);
-    sections[key] = [s.enrolled, s.limit, s.waitlist];
+    // Barrett sometimes publishes the instructor before Ohio State's class
+    // API does. Keep the raw listing beside the seat counts so the browser can
+    // use it only as a fallback; an empty fourth field costs nothing useful and
+    // old three-column snapshots remain readable.
+    sections[key] = s.instructor
+      ? [s.enrolled, s.limit, s.waitlist, s.instructor]
+      : [s.enrolled, s.limit, s.waitlist];
   }
 
   const groups = linkGroups([...byClass.values()]);
@@ -694,8 +711,8 @@ async function main() {
   // not publish from one it has simply not fetched yet.
   const indexBytes = await writeJson(join(OUT_DIR, INDEX_NAME), {
     source: `${BASE}/`,
-    fields: ['enrolled', 'limit', 'waitlist'],
-    note: 'Barrett rebuilds a live term once a day around 06:50 Eastern and freezes a term once it is over, so sourceUpdated differs per term. A missing class number means unknown, not zero.',
+    fields: ['enrolled', 'limit', 'waitlist', 'instructor'],
+    note: 'Barrett rebuilds a live term once a day around 06:50 Eastern and freezes a term once it is over, so sourceUpdated differs per term. Instructor is Barrett\'s compact listing and is used only when Ohio State has not published a primary instructor. A missing class number means unknown, not zero.',
     terms: entries,
   });
   console.log(`wrote data/${INDEX_NAME} (${indexBytes} bytes)`);

tests/contract.test.js

@@ -125,7 +125,7 @@ test("courses.json keeps its shape", async () => {
 test("seats.json and the term files it lists agree", async () => {
   const index = await read("seats.json");
   assert.deepEqual(Object.keys(index), ["source", "fields", "note", "terms"]);
-  assert.deepEqual(index.fields, ["enrolled", "limit", "waitlist"]);
+  assert.deepEqual(index.fields, ["enrolled", "limit", "waitlist", "instructor"]);
   assert.ok(index.terms.length > 0);
 
   for (const entry of index.terms) {
@@ -141,8 +141,13 @@ test("seats.json and the term files it lists agree", async () => {
     assert.equal(rows.length, entry.sections, `${entry.file} does not hold what the index says`);
     for (const [classNumber, row] of rows) {
       assert.match(classNumber, /^\d+$/);
-      assert.equal(row.length, 3, `${entry.file} ${classNumber} is not enrolled/limit/waitlist`);
-      for (const value of row) assert.equal(typeof value, "number");
+      assert.ok(row.length === 3 || row.length === 4,
+        `${entry.file} ${classNumber} is not enrolled/limit/waitlist[/instructor]`);
+      for (const value of row.slice(0, 3)) assert.equal(typeof value, "number");
+      if (row.length === 4) {
+        assert.equal(typeof row[3], "string");
+        assert.ok(row[3].trim(), `${entry.file} ${classNumber} has an empty instructor column`);
+      }
     }
   }
 });

tests/fetch-seats.test.js

@@ -96,6 +96,14 @@ describe("where the column header is", () => {
     assert.deepEqual(out.failures, []);
     assert.equal(out.sections.length, 2);
   });
+
+  test("a short-session marker is not stored as an instructor", () => {
+    const text = barrettFile("CSE", "1268", [
+      { catalog: "2501", classNumber: "7099", enrolled: 0, limit: 5, instructor: "{7W2}" },
+    ]);
+    const out = parseSubjectFile("CSE", "1268", text);
+    assert.equal(out.sections[0].instructor, "");
+  });
 });
 
 describe("what holds a term back", () => {
@@ -125,7 +133,7 @@ describe("what holds a term back", () => {
       assert.equal(stats.sectionsParsed, 44, "the other 11 subjects still parsed");
       assert.match(fetchErrors[0], /SUBJ07/);
       assert.match(fetchErrors[0], /403/);
-      assert.deepEqual(snapshot.sections["10000"], [26, 40, 0], "SUBJ00 is in the snapshot");
+      assert.deepEqual(snapshot.sections["10000"], [26, 40, 0, "M.Mallon"], "SUBJ00 is in the snapshot");
       assert.equal(snapshot.sections["10700"], undefined, "SUBJ07 is not, its sections read as unknown");
     } finally {
       restore();

tests/fixtures.js

@@ -71,7 +71,7 @@ export function taught(classNumber, days, start, end, names, opts = {}) {
 // one file per term, so the loader under test does the real two-step fetch.
 export const SEATS_INDEX = {
   source: "https://www.asc.ohio-state.edu/barrett.3/schedule/",
-  fields: ["enrolled", "limit", "waitlist"],
+  fields: ["enrolled", "limit", "waitlist", "instructor"],
   note: "A missing class number means unknown, not zero.",
   terms: [
     { term: "1262", termName: "Spring 2026", sourceUpdated: "2026-04-27", sections: 2, file: "seats-1262.json" },
@@ -83,8 +83,8 @@ export const SEATS_TERMS = {
   "1268": {
     term: "1268",
     sections: {
-      "1001": [30, 40, 0],    // open
-      "1002": [40, 40, 3],    // exactly full, three waiting
+      "1001": [30, 40, 0, "P.Bucci"], // open, with Barrett's earlier instructor listing
+      "1002": [40, 40, 3, "S.Gomori, A.Meghrazi (TA), J.Weiler (SI)"], // exactly full, three waiting
       "1003": [41, 40, 1],    // over cap, which OSU's own API calls open
       "1004": [0, 0, 1],      // no published capacity, someone already waiting
       "1005": [12],           // malformed, too short

tests/format.test.js

@@ -212,6 +212,14 @@ test("instructorsOf survives missing meetings and missing instructors", () => {
   assert.deepEqual(instructorsOf({ meetings: [{ startTime: "9:00 AM" }] }), []);
 });
 
+test("instructorsOf uses an early Barrett listing kept off the meeting", () => {
+  const people = instructorsOf({
+    meetings: [],
+    fallbackInstructors: [{ displayName: "P. Bucci", role: "PI", source: "barrett" }],
+  });
+  assert.deepEqual(people, [{ name: "P. Bucci", email: null, role: "PI", source: "barrett" }]);
+});
+
 // Regression, #82. CSE 2112 class 8823 comes back with ten meetings for one
 // Tuesday class, alternating the room label between BE 120 and Baker Syst.
 // Printing a line per meeting turned that row into nine repeats.

tests/seats.test.js

@@ -12,6 +12,33 @@ test("seatsFor reports an open section", () => {
   assert.deepEqual(seats.seatsFor("1001", "1268"), { enrolled: 30, limit: 40, waitlist: 0, full: false });
 });
 
+test("Barrett instructors are parsed without changing seat reads", () => {
+  assert.deepEqual(seats.instructorsFor("1001", "1268"), [
+    { displayName: "P. Bucci", email: null, role: "PI", source: "barrett" },
+  ]);
+  assert.deepEqual(seats.instructorsFor("1002", "1268"), [
+    { displayName: "S. Gomori", email: null, role: "PI", source: "barrett" },
+    { displayName: "A. Meghrazi", email: null, role: "TA", source: "barrett" },
+    { displayName: "J. Weiler", email: null, role: "SI", source: "barrett" },
+  ]);
+  assert.deepEqual(seats.instructorsFor("1003", "1268"), [], "old three-column rows stay compatible");
+});
+
+test("Barrett fills an unpublished primary instructor without replacing Ohio State's", () => {
+  const missing = [{ course: {}, sections: [{ classNumber: "1001", meetings: [] }] }];
+  const [filled] = seats.withSeatInstructors(missing, "1268");
+  assert.equal(filled.sections[0].fallbackInstructors[0].displayName, "P. Bucci");
+  assert.notEqual(filled.sections[0], missing[0].sections[0], "the API response is not mutated");
+
+  const published = [{ course: {}, sections: [{
+    classNumber: "1001",
+    meetings: [{ instructors: [{ displayName: "Paolo Bucci", role: "PI" }] }],
+  }] }];
+  const [kept] = seats.withSeatInstructors(published, "1268");
+  assert.equal(kept.sections[0], published[0].sections[0]);
+  assert.equal(kept.sections[0].fallbackInstructors, undefined);
+});
+
 test("seatsFor calls a section at capacity full", () => {
   const row = seats.seatsFor("1002", "1268");
   assert.equal(row.full, true);