JoshHeaps.Net/Pages/Casino/TexasHoldem.cshtml

@@ -313,6 +313,41 @@
             </p>
         </section>
 
+        <section class="ruling">
+            <h3>A short all-in doesn't reopen the betting</h3>
+            <p>
+                Somebody shoving in less than a full raise — say $3 more when the last
+                raise was $8 — does not give the players behind them another go. Anyone
+                who has already acted owes the difference or folds; they don't get to
+                raise again because a short stack happened to land between them.
+            </p>
+            <p>
+                A player who hadn't acted yet keeps full rights and may still raise, and
+                the minimum raise stays measured off the last <em>full</em> raise, not
+                off the short one. The action bar follows this for you.
+            </p>
+        </section>
+
+        <section class="ruling">
+            <h3>Chips nobody called come back</h3>
+            <p>
+                Bet more than anyone was able to call and the excess is returned to you
+                before the showdown — it was never contested, so it isn't part of the
+                pot. The pot breakdown shows it as "uncalled" rather than pretending it's
+                a side pot you could win.
+            </p>
+        </section>
+
+        <section class="ruling">
+            <h3>The odd chip in a split pot</h3>
+            <p>
+                When a chopped pot won't divide evenly, the odd chip goes to the first
+                player left of the button, not to whoever the dealer happened to tick
+                first. Pot payouts here order the winners that way, so the leftover lands
+                on the right seat every time.
+            </p>
+        </section>
+
         <p class="rulingsSource">
             Follows the Tournament Directors Association rules, which most rooms and
             home games take their lead from.

JoshHeaps.Net/wwwroot/js/casino/holdem/betting.js

@@ -153,14 +153,33 @@ const Betting = {
         const delta = this.round(target - this.committed(player));
         const moved = this.putIn(state, index, delta);
         const newBet = this.committed(player);
+        const previousBet = state.currentBet || 0;
+
+        if (newBet > previousBet) {
+            const increase = this.round(newBet - previousBet);
+            // What a full raise would have had to be: at least as much again as the
+            // last one, or the big blind if there hasn't been a raise yet.
+            const fullRaise = this.round(state.lastRaiseSize || state.bigBlind || 0);
+            const isFullRaise = increase >= fullRaise - this.EPSILON_CHIPS;
 
-        if (newBet > (state.currentBet || 0)) {
-            state.lastRaiseSize = this.round(newBet - (state.currentBet || 0));
             state.currentBet = newBet;
-            // A raise reopens the action: everyone else owes a response again.
-            state.seats.forEach((p, i) => {
-                if (i !== index && p.inHand && !p.folded) p.hasActed = false;
-            });
+
+            if (isFullRaise) {
+                state.lastRaiseSize = increase;
+                // A real raise reopens the action: everyone else owes a response again.
+                state.seats.forEach((p, i) => {
+                    if (i !== index && p.inHand && !p.folded) p.hasActed = false;
+                });
+            }
+            // Otherwise this is a short all-in — somebody with less than a full raise
+            // left shoving it in. The most misread rule in poker: it does *not* reopen
+            // the betting to anyone who has already acted. They owe the difference or
+            // they fold; they don't get to raise again because a short stack happened
+            // to be between them. Players yet to act keep their full rights, which
+            // they do here because their hasActed is already false.
+            //
+            // lastRaiseSize deliberately isn't lowered either, or the next legal raise
+            // would be computed off the short amount and come out too small.
         }
 
         player.hasActed = true;

tests/holdem/reopeningBetting.test.js

@@ -0,0 +1,143 @@
+// When does a bet reopen the action? The most misread rule in poker, and the one a
+// home game argues about longest: a player shoving in less than a full raise does not
+// give everybody behind them another go.
+//
+// TDA Rule 44 — an all-in wager of less than a full raise does not reopen the betting
+// to a player who has already acted and is not facing a full raise.
+const { test, describe } = require("node:test");
+const assert = require("node:assert/strict");
+const { Betting, makeTable, chipsOnTable } = require("./load");
+
+const actedFlags = state => state.seats
+    .map((p, i) => ({ seat: i, acted: p.hasActed, live: p.inHand && !p.folded }))
+    .filter(s => s.live);
+
+describe("a short all-in does not reopen the betting", () => {
+    // Blinds 1/2. Seat 4 raises to 10 (a full raise of 8). Seat 1 calls.
+    // Seat 2 is all-in for 13 — three more, where a full raise needs eight.
+    const shortAllInTable = () => {
+        const state = makeTable({ seatCount: 4, seated: [0, 1, 2, 3], stack: 100, dealerSeatIndex: 0 });
+        state.seats[1].stack = 13;
+        Betting.beginHand(state);
+        Betting.raiseTo(state, 3, 10);
+        Betting.call(state, 0);
+        return state;
+    };
+
+    test("players who already acted are not asked to act again", () => {
+        const state = shortAllInTable();
+        assert.equal(state.seats[0].hasActed, true, "seat 1 has called");
+        assert.equal(state.seats[3].hasActed, true, "seat 4 has raised");
+
+        Betting.allIn(state, 1);
+
+        assert.equal(state.seats[0].hasActed, true, "seat 1 must not be reopened");
+        assert.equal(state.seats[3].hasActed, true, "seat 4 must not be reopened");
+    });
+
+    test("but they do still owe the difference", () => {
+        const state = shortAllInTable();
+        Betting.allIn(state, 1);
+
+        assert.equal(Betting.toCall(state, state.seats[0]), 3, "seat 1 owes the extra 3");
+        assert.equal(Betting.isStreetComplete(state), false, "so the street isn't over");
+    });
+
+    test("a player who had not acted yet keeps full rights", () => {
+        const state = shortAllInTable();
+        assert.equal(state.seats[2].hasActed, false, "seat 3 hasn't acted");
+        Betting.allIn(state, 1);
+        assert.equal(state.seats[2].hasActed, false, "and still hasn't — they may still raise");
+    });
+
+    test("the minimum raise is not shrunk by the short all-in", () => {
+        const state = shortAllInTable();
+        assert.equal(state.lastRaiseSize, 8);
+
+        Betting.allIn(state, 1);
+
+        assert.equal(state.lastRaiseSize, 8, "still the last *full* raise");
+        assert.equal(Betting.minRaiseTo(state), 21, "13 to call plus a full raise of 8");
+    });
+
+    test("calling the short all-in ends the street", () => {
+        const state = shortAllInTable();
+        Betting.allIn(state, 1);
+        Betting.call(state, 2);   // seat 3, who had full rights, just calls
+        Betting.call(state, 3);
+        Betting.call(state, 0);
+        assert.equal(Betting.isStreetComplete(state), true);
+    });
+
+    test("no chips are created or lost by any of it", () => {
+        const state = makeTable({ seatCount: 4, seated: [0, 1, 2, 3], stack: 100, dealerSeatIndex: 0 });
+        state.seats[1].stack = 13;
+        const start = chipsOnTable(state);
+        Betting.beginHand(state);
+        Betting.raiseTo(state, 3, 10);
+        Betting.call(state, 0);
+        Betting.allIn(state, 1);
+        Betting.call(state, 2);
+        Betting.call(state, 3);
+        Betting.call(state, 0);
+        assert.equal(chipsOnTable(state), start);
+    });
+});
+
+describe("a full raise still reopens the betting", () => {
+    test("an all-in that is a full raise or more reopens everyone", () => {
+        const state = makeTable({ seatCount: 4, seated: [0, 1, 2, 3], stack: 100, dealerSeatIndex: 0 });
+        state.seats[1].stack = 40;
+        Betting.beginHand(state);
+        Betting.raiseTo(state, 3, 10);
+        Betting.call(state, 0);
+
+        Betting.allIn(state, 1);   // to 40: an increase of 30, well over the 8 needed
+
+        assert.equal(state.seats[0].hasActed, false, "seat 1 gets another go");
+        assert.equal(state.seats[3].hasActed, false, "and so does seat 4");
+        assert.equal(state.lastRaiseSize, 30);
+        assert.equal(Betting.minRaiseTo(state), 70);
+    });
+
+    test("an ordinary raise reopens everyone", () => {
+        const state = makeTable({ seatCount: 4, seated: [0, 1, 2, 3], dealerSeatIndex: 0 });
+        Betting.beginHand(state);
+        Betting.call(state, 3);
+        Betting.call(state, 0);
+        assert.equal(state.seats[3].hasActed, true);
+
+        Betting.raiseTo(state, 1, 10);
+
+        assert.equal(state.seats[3].hasActed, false);
+        assert.equal(state.seats[0].hasActed, false);
+    });
+
+    test("a raise exactly the size of the last one counts as full", () => {
+        const state = makeTable({ seatCount: 4, seated: [0, 1, 2, 3], stack: 100, dealerSeatIndex: 0 });
+        Betting.beginHand(state);
+        Betting.raiseTo(state, 3, 10);      // raise of 8
+        Betting.call(state, 0);
+
+        Betting.raiseTo(state, 1, 18);      // exactly 8 more — a legal minimum raise
+
+        assert.equal(state.seats[0].hasActed, false, "a minimum raise still reopens");
+        assert.equal(state.lastRaiseSize, 8);
+    });
+
+    test("the first raise of a street is measured against the big blind", () => {
+        const state = makeTable({ seatCount: 4, seated: [0, 1, 2, 3], stack: 100, dealerSeatIndex: 0 });
+        Betting.beginHand(state);
+        Betting.call(state, 3);
+        Betting.call(state, 0);
+        Betting.call(state, 1);
+        Betting.check(state, 2);
+        Betting.closeStreet(state);         // to the flop, no bet yet
+
+        const first = Betting.nextToAct(state, state.dealerSeatIndex);
+        Betting.raiseTo(state, first, 2);   // a bet of exactly one big blind
+
+        const others = state.seats.filter((p, i) => p.inHand && !p.folded && i !== first);
+        assert.ok(others.every(p => p.hasActed === false), "a full-sized opening bet reopens everyone");
+    });
+});