From 5b01423f06103e2b09f42bf59d0532e39c70569d Mon Sep 17 00:00:00 2001
From: Runxi Yu <me@runxiyu.org>
Date: Wed, 17 Sep 2025 01:43:19 +0800
Subject: [PATCH] Fix some btree and swiss bugs

o Handle case where key is equal to promoted median after splitting full
  child
o Descend with new index after merging children
o Fix weird slice alloc bug in swiss

---
 ds/map/btree/internal.ha | 16 ++++++++++++----
 ds/map/swiss/internal.ha |  2 +-
 ds/map/swiss/new.ha      |  2 +-

diff --git a/ds/map/btree/internal.ha b/ds/map/btree/internal.ha
index f16cbd67dc5dde90ef5986204157120af2aed0c5..d73038ca42922c5f9957db12c1c1d895742126ef 100644
--- a/ds/map/btree/internal.ha
+++ b/ds/map/btree/internal.ha
@@ -88,10 +88,14 @@ 	};
 
 	if (len(x.children[i].keys) == 2 * m.t - 1) {
 		split_child(m, x, i)?;
-		if (cmp_u8slice((&key: const *opaque),
-				(&x.keys[i]: const *opaque)) > 0) {
-			insert_nonfull(m, x.children[i + 1], key, val)?;
+		let cmp = cmp_u8slice((&key: const *opaque),
+			(&x.keys[i]: const *opaque));
+		if (cmp == 0) {
+			x.vals[i] = val;
 			return;
+		};
+		if (cmp > 0) {
+			i += 1;
 		};
 	};
 	insert_nonfull(m, x.children[i], key, val)?;
@@ -169,8 +173,9 @@
 fn pop_max(m: *map, x: *node) ([]u8, *opaque) = {
 	let cur = x;
 	for (!cur.leaf) {
+		let last_before = len(cur.children) - 1;
+		ensure_child_has_space(m, cur, last_before);
 		let last = len(cur.children) - 1;
-		ensure_child_has_space(m, cur, last);
 		cur = cur.children[last];
 	};
 	let k = cur.keys[len(cur.keys) - 1];
@@ -232,5 +237,8 @@ 		return;
 	};
 
 	ensure_child_has_space(m, x, i);
+	if (i >= len(x.children)) {
+		i = len(x.children) - 1;
+	};
 	return delete_rec(m, x.children[i], key);
 };
diff --git a/ds/map/swiss/internal.ha b/ds/map/swiss/internal.ha
index 125d034d0a24993150dcc2ddba968efd2fae14fb..54f58aa847472d3f30927b3dab897738807e56df 100644
--- a/ds/map/swiss/internal.ha
+++ b/ds/map/swiss/internal.ha
@@ -72,7 +72,7 @@ };
 
 fn resize(m: *map, new_groups_len: size) (void | nomem) = {
 	if (new_groups_len == 0) new_groups_len = 1;
-	let gs: []group = match (alloc([group{...}...]: []group, new_groups_len)) {
+	let gs = match (alloc([group{...}...], new_groups_len)) {
 	case let a: []group => yield a;
 	case nomem => return nomem;
 	};
diff --git a/ds/map/swiss/new.ha b/ds/map/swiss/new.ha
index 3a342c40296ed4480531407086c945826cdfadaf..f10e0bce9ccb96bf0b60bad0c11b4c2a857c2fc4 100644
--- a/ds/map/swiss/new.ha
+++ b/ds/map/swiss/new.ha
@@ -22,7 +22,7 @@ 		v *= 2;
 	};
 	let groups_count = v;
 
-	let gs: []group = match (alloc([group{...}...]: []group, groups_count)) {
+	let gs = match (alloc([group{...}...], groups_count)) {
 	case let a: []group => yield a;
 	case nomem => return nomem;
 	};

-- 
2.48.1