From dd6758d543e7672ed5cefa0dc9e1749c2a66b8db Mon Sep 17 00:00:00 2001
From: Kevin J Bowers <kbowers@jumptrading.com>
Date: Sun, 16 Apr 2023 13:23:10 -0500
Subject: [PATCH] Unit test coverage for map_giant iterator and fix

---
 src/util/tmpl/fd_map_giant.c   |  2 +-
 src/util/tmpl/test_map_giant.c | 35 ++++++++++++++++++++++++++++++++++
 2 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/src/util/tmpl/fd_map_giant.c b/src/util/tmpl/fd_map_giant.c
index 07cd3f57a7..9b40a3f8dd 100644
--- a/src/util/tmpl/fd_map_giant.c
+++ b/src/util/tmpl/fd_map_giant.c
@@ -453,7 +453,7 @@ MAP_(iter_done)( MAP_T const * join,
 FD_FN_PURE static inline MAP_(iter_t)
 MAP_(iter_next)( MAP_T const * join,
                  MAP_(iter_t)  ele_rem ) {
-  for( ; ele_rem; ele_rem-- ) if( !MAP_(private_unbox_tag)( join[ ele_rem-1UL ].MAP_NEXT ) ) break;
+  for( ele_rem--; ele_rem; ele_rem-- ) if( !MAP_(private_unbox_tag)( join[ ele_rem-1UL ].MAP_NEXT ) ) break;
   return ele_rem;
 }
 
diff --git a/src/util/tmpl/test_map_giant.c b/src/util/tmpl/test_map_giant.c
index f61625f473..ab1c4f70a6 100644
--- a/src/util/tmpl/test_map_giant.c
+++ b/src/util/tmpl/test_map_giant.c
@@ -4,6 +4,7 @@ struct pair {
   ulong mykey;
   ulong mynext;
   uint  val;
+  uint  tag;
 };
 
 typedef struct pair pair_t;
@@ -54,6 +55,7 @@ main( int     argc,
     ref[idx].mykey  = (1UL<<63) | (fd_rng_ulong( rng )<<9) | idx; /* Every map key is unique and non-zero */
     ref[idx].mynext = fd_rng_ulong( rng );
     ref[idx].val    = fd_rng_uint( rng );
+    ref[idx].tag    = 0U;
     tst[idx] = ref[idx];
   }
   sort_pair_inplace( ref, max );
@@ -95,6 +97,8 @@ main( int     argc,
 
   FD_TEST( !map_verify( map ) );
 
+  uint tag = 0U;
+
   for( ulong iter=0UL; iter<iter_max; iter++ ) {
     if( !(iter % 100UL) ) FD_LOG_NOTICE(( "Iter %lu", iter ));
     shuffle_pair( rng, tst, max ); /* Generate a randomized insertion order */
@@ -104,6 +108,21 @@ main( int     argc,
     for( ulong i=0UL; i<max; i++ ) {
       FD_TEST( !map_is_full( map ) );
 
+      /* Try iterating over map (incl empty case) */
+      tag++;
+      ulong cnt = 0UL;
+      for( map_iter_t iter = map_iter_init( map ); !map_iter_done( map, iter ); iter = map_iter_next( map, iter ) ) {
+        pair_t *       p0 = map_iter_ele(       map, iter );
+        pair_t const * p1 = map_iter_ele_const( map, iter );
+        FD_TEST( p0 );
+        FD_TEST( p1 );
+        FD_TEST( p1==(pair_t const *)p0 );
+        FD_TEST( p0->tag!=tag );
+        p0->tag = tag;
+        cnt++;
+      }
+      FD_TEST( cnt==i );
+
       ulong ki = tst[i].mykey;
       uint  vi = tst[i].val;
 
@@ -133,6 +152,22 @@ main( int     argc,
     /* Make sure map is full at this point */
     FD_TEST( map_is_full( map ) );
 
+    do {
+      tag++;
+      ulong cnt = 0UL;
+      for( map_iter_t iter = map_iter_init( map ); !map_iter_done( map, iter ); iter = map_iter_next( map, iter ) ) {
+        pair_t *       p0 = map_iter_ele(       map, iter );
+        pair_t const * p1 = map_iter_ele_const( map, iter );
+        FD_TEST( p0 );
+        FD_TEST( p1 );
+        FD_TEST( p1==(pair_t const *)p0 );
+        FD_TEST( p0->tag!=tag );
+        p0->tag = tag;
+        cnt++;
+      }
+      FD_TEST( cnt==max );
+    } while(0);
+
     /* Generate a different randomized deletion order */
     shuffle_pair( rng, tst, max );