Catch-up: send CHATHISTORY TARGETS newer bound first (#216)

client/js/irc/catchup.ts

@@ -544,7 +544,8 @@ function sendTargets(client: IrcClient, state: TargetsState): void {
 	// From the start: the server's index moves on messages only (not joins,
 	// parts, topics, redactions), so the newest line we hold can be well past
 	// a quiet channel's newest message, and a window starting there would
-	// leave it out. Newest first, so a long history costs nothing extra.
+	// leave it out. The limit counts from the first bound, so the newer one
+	// goes first: the newest `limit` targets, as in the spec's example.
 	const since = new Date(0);
 	const until = new Date(Date.now() + TARGETS_AHEAD_MS);
 	const tags: Record<string, string> = {};
@@ -559,8 +560,8 @@ function sendTargets(client: IrcClient, state: TargetsState): void {
 		command: "CHATHISTORY",
 		params: [
 			"TARGETS",
-			`timestamp=${since.toISOString()}`,
 			`timestamp=${until.toISOString()}`,
+			`timestamp=${since.toISOString()}`,
 			String(historyLimit(client, TARGETS_LIMIT)),
 		],
 	});

docs/projects/connect-burst.md

@@ -200,7 +200,7 @@ The background catch-up used to go in JOIN order, so the channel that had
 been written to waited behind every quiet one, and a reconnect fetched every
 channel whether anything had happened in it or not. Now the first channel
 to need the background queue on a connection asks one
-`CHATHISTORY TARGETS timestamp=<from> timestamp=<a day past now> <limit>`
+`CHATHISTORY TARGETS timestamp=<a day past now> timestamp=<from> <limit>`
 (at the front of the queue) and the catch-up of every other channel is
 parked until it answers (`catchup.ts`):
 
@@ -210,8 +210,10 @@ parked until it answers (`catchup.ts`):
   now because nefarious2 drops a target whose newest message is later than
   it (`filter_targets_window`), and a server clock ahead of ours would lose
   exactly the channel just written to. The limit is 100 (capped by ISUPPORT
-  `CHATHISTORY`). nefarious2 lists the channels we may read history of:
-  those we are a member of, and `+H` (public history) channels without
+  `CHATHISTORY`). The newer bound goes first: TARGETS takes BETWEEN's
+  semantics, the limit counting from the first argument, so oldest first
+  would get the oldest `limit` from a server that follows the spec (#216).
+  nefarious2 lists the channels we may read history of: those we are a member of, and `+H` (public history) channels without
   membership (`check_history_access`). So it is asked once the JOINs are
   in, newest first; a listed `+H` channel we are not in is simply not
   among the parked ones.

test/irc/catchup.ts

@@ -189,11 +189,12 @@ describe("Connect burst: batched JOIN, catch-up paced by fake lag, lazy MODE (ir
 			"#four",
 		]);
 
-		// One TARGETS, first in the queue, from the start of time (nothing is
-		// held yet) to a day past now.
+		// One TARGETS, first in the queue, from a day past now back to the
+		// start of time (nothing is held yet): newer bound first, so a server
+		// following the spec counts the limit from the newest (issue #216).
 		const [targets] = collect(h, 1).map((s) => s.line);
 		expect(targets).to.match(
-			/^@label=tg\d+ CHATHISTORY TARGETS timestamp=1970-01-01T00:00:00\.000Z timestamp=2026-08-28T12:00:\d\d\.\d{3}Z 100$/
+			/^@label=tg\d+ CHATHISTORY TARGETS timestamp=2026-08-28T12:00:\d\d\.\d{3}Z timestamp=1970-01-01T00:00:00\.000Z 100$/
 		);
 		answerTargets(h, targets, [
 			["#three", "2026-08-27T11:59:00.000Z"],
@@ -604,7 +605,9 @@ describe("Connect burst: batched JOIN, catch-up paced by fake lag, lazy MODE (ir
 			const h = heldThenDropped(HELD);
 			const [targets] = collect(h, 1, isTargets).map((s) => s.line);
 			// From the start: events move what we hold, not the server's index.
-			expect(targets).to.include("TARGETS timestamp=1970-01-01T00:00:00.000Z ");
+			expect(targets).to.match(
+				/ TARGETS timestamp=\S+ timestamp=1970-01-01T00:00:00\.000Z \d+$/
+			);
 			answerTargets(h, targets, [
 				["#three", "2026-08-27T12:05:00.000Z"], // written to since
 				["#seance", "2026-08-27T12:04:00.000Z"], // the active one: served already
@@ -664,7 +667,9 @@ describe("Connect burst: batched JOIN, catch-up paced by fake lag, lazy MODE (ir
 			h.sent();
 			joinAll(h);
 			const [targets] = collect(h, 1, isTargets).map((s) => s.line);
-			expect(targets).to.include("TARGETS timestamp=1970-01-01T00:00:00.000Z ");
+			expect(targets).to.match(
+				/ TARGETS timestamp=\S+ timestamp=1970-01-01T00:00:00\.000Z \d+$/
+			);
 			answerTargets(h, targets, []);
 			expect(fetched(collect(h, 20).map((s) => s.line))).to.deep.equal([
 				"#two",