From 8944a064d0fd7947b8c2b6c761be3e3a0c9073af Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?V=C3=ADt=20Ondruch?= <vondruch@redhat.com>
Date: Fri, 22 Dec 2023 14:16:48 +0100
Subject: [PATCH 1/2] Revert "compare_by_identity: remove alloc for non-empty
 Hash"

This reverts commit 11fa76b1b521072c200c78ea023960221ff426d6.
---
 hash.c | 13 ++++---------
 1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/hash.c b/hash.c
index 78e9d9a2d6..f6525ba4a5 100644
--- a/hash.c
+++ b/hash.c
@@ -4377,16 +4377,13 @@ rb_hash_compare_by_id(VALUE hash)
     if (hash_iterating_p(hash)) {
         rb_raise(rb_eRuntimeError, "compare_by_identity during iteration");
     }
+    ar_force_convert_table(hash, __FILE__, __LINE__);
+    HASH_ASSERT(RHASH_ST_TABLE_P(hash));
 
     if (RHASH_TABLE_EMPTY_P(hash)) {
         // Fast path: There's nothing to rehash, so we don't need a `tmp` table.
-        // We're most likely an AR table, so this will need an allocation.
-        ar_force_convert_table(hash, __FILE__, __LINE__);
-        HASH_ASSERT(RHASH_ST_TABLE_P(hash));
-
         RHASH_ST_TABLE(hash)->type = &identhash;
-    }
-    else {
+    } else {
         // Slow path: Need to rehash the members of `self` into a new
         // `tmp` table using the new `identhash` compare/hash functions.
         tmp = hash_alloc(0);
@@ -4394,10 +4391,8 @@ rb_hash_compare_by_id(VALUE hash)
         identtable = RHASH_ST_TABLE(tmp);
 
         rb_hash_foreach(hash, rb_hash_rehash_i, (VALUE)tmp);
-        rb_hash_free(hash);
 
-        // We know for sure `identtable` is an st table,
-        // so we can skip `ar_force_convert_table` here.
+        rb_hash_free(hash);
         RHASH_ST_TABLE_SET(hash, identtable);
         RHASH_ST_CLEAR(tmp);
     }

From f5c415300ffe63e41e46c6b88b8634a3bad0c7c2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?V=C3=ADt=20Ondruch?= <vondruch@redhat.com>
Date: Fri, 22 Dec 2023 14:17:14 +0100
Subject: [PATCH 2/2] Revert "compare_by_identity: remove alloc for empty Hash"

This reverts commit b5c6c0122f5b010cb5f43e7a236c4ba2b1d56a2a.
---
 hash.c | 21 +++++++--------------
 1 file changed, 7 insertions(+), 14 deletions(-)

diff --git a/hash.c b/hash.c
index f6525ba4a5..cf83675c70 100644
--- a/hash.c
+++ b/hash.c
@@ -4380,22 +4380,15 @@ rb_hash_compare_by_id(VALUE hash)
     ar_force_convert_table(hash, __FILE__, __LINE__);
     HASH_ASSERT(RHASH_ST_TABLE_P(hash));
 
-    if (RHASH_TABLE_EMPTY_P(hash)) {
-        // Fast path: There's nothing to rehash, so we don't need a `tmp` table.
-        RHASH_ST_TABLE(hash)->type = &identhash;
-    } else {
-        // Slow path: Need to rehash the members of `self` into a new
-        // `tmp` table using the new `identhash` compare/hash functions.
-        tmp = hash_alloc(0);
-        hash_st_table_init(tmp, &identhash, RHASH_SIZE(hash));
-        identtable = RHASH_ST_TABLE(tmp);
+    tmp = hash_alloc(0);
+    hash_st_table_init(tmp, &identhash, RHASH_SIZE(hash));
+    identtable = RHASH_ST_TABLE(tmp);
 
-        rb_hash_foreach(hash, rb_hash_rehash_i, (VALUE)tmp);
+    rb_hash_foreach(hash, rb_hash_rehash_i, (VALUE)tmp);
 
-        rb_hash_free(hash);
-        RHASH_ST_TABLE_SET(hash, identtable);
-        RHASH_ST_CLEAR(tmp);
-    }
+    rb_hash_free(hash);
+    RHASH_ST_TABLE_SET(hash, identtable);
+    RHASH_ST_CLEAR(tmp);
 
     return hash;
 }