gh-91404: Revert "bpo-23689: re module, fix memory leak when a match is terminated by a signal or allocation failure (GH-32283) (#93882)

Revert "bpo-23689: re module, fix memory leak when a match is terminated by a signal or memory allocation failure (GH-32283)"

This reverts commit 6e3eee5c11b539e9aab39cff783acf57838c355a.

Manual fixups to increase the MAGIC number and to handle conflicts with
a couple of changes that landed after that.

Thanks for reviews by Ma Lin and Serhiy Storchaka.

1 files changed, 17 insertions, 13 deletions

diff --git a/Modules/_sre/sre_lib.h b/Modules/_sre/sre_lib.h
index 1e5b501..fb4c18b 100644
--- a/Modules/_sre/sre_lib.h
+++ b/Modules/_sre/sre_lib.h
@@ -1079,12 +1079,17 @@ dispatch:
                by the UNTIL operator (MAX_UNTIL, MIN_UNTIL) */
             /* <REPEAT> <skip> <1=min> <2=max>
                <3=repeat_index> item <UNTIL> tail */
-            TRACE(("|%p|%p|REPEAT %d %d %d\n", pattern, ptr,
-                   pattern[1], pattern[2], pattern[3]));
-
-            /* install repeat context */
-            ctx->u.rep = &state->repeats_array[pattern[3]];
+            TRACE(("|%p|%p|REPEAT %d %d\n", pattern, ptr,
+                   pattern[1], pattern[2]));
 
+            /* install new repeat context */
+            /* TODO(https://github.com/python/cpython/issues/67877): Fix this
+             * potential memory leak. */
+            ctx->u.rep = (SRE_REPEAT*) PyObject_Malloc(sizeof(*ctx->u.rep));
+            if (!ctx->u.rep) {
+                PyErr_NoMemory();
+                RETURN_FAILURE;
+            }
             ctx->u.rep->count = -1;
             ctx->u.rep->pattern = pattern;
             ctx->u.rep->prev = state->repeat;
@@ -1094,6 +1099,7 @@ dispatch:
             state->ptr = ptr;
             DO_JUMP(JUMP_REPEAT, jump_repeat, pattern+pattern[0]);
             state->repeat = ctx->u.rep->prev;
+            PyObject_Free(ctx->u.rep);
 
             if (ret) {
                 RETURN_ON_ERROR(ret);
@@ -1103,8 +1109,7 @@ dispatch:
 
         TARGET(SRE_OP_MAX_UNTIL):
             /* maximizing repeat */
-            /* <REPEAT> <skip> <1=min> <2=max>
-               <3=repeat_index> item <MAX_UNTIL> tail */
+            /* <REPEAT> <skip> <1=min> <2=max> item <MAX_UNTIL> tail */
 
             /* FIXME: we probably need to deal with zero-width
                matches in here... */
@@ -1124,7 +1129,7 @@ dispatch:
                 /* not enough matches */
                 ctx->u.rep->count = ctx->count;
                 DO_JUMP(JUMP_MAX_UNTIL_1, jump_max_until_1,
-                        ctx->u.rep->pattern+4);
+                        ctx->u.rep->pattern+3);
                 if (ret) {
                     RETURN_ON_ERROR(ret);
                     RETURN_SUCCESS;
@@ -1146,7 +1151,7 @@ dispatch:
                 DATA_PUSH(&ctx->u.rep->last_ptr);
                 ctx->u.rep->last_ptr = state->ptr;
                 DO_JUMP(JUMP_MAX_UNTIL_2, jump_max_until_2,
-                        ctx->u.rep->pattern+4);
+                        ctx->u.rep->pattern+3);
                 DATA_POP(&ctx->u.rep->last_ptr);
                 if (ret) {
                     MARK_POP_DISCARD(ctx->lastmark);
@@ -1171,8 +1176,7 @@ dispatch:
 
         TARGET(SRE_OP_MIN_UNTIL):
             /* minimizing repeat */
-            /* <REPEAT> <skip> <1=min> <2=max>
-               <3=repeat_index> item <MIN_UNTIL> tail */
+            /* <REPEAT> <skip> <1=min> <2=max> item <MIN_UNTIL> tail */
 
             ctx->u.rep = state->repeat;
             if (!ctx->u.rep)
@@ -1189,7 +1193,7 @@ dispatch:
                 /* not enough matches */
                 ctx->u.rep->count = ctx->count;
                 DO_JUMP(JUMP_MIN_UNTIL_1, jump_min_until_1,
-                        ctx->u.rep->pattern+4);
+                        ctx->u.rep->pattern+3);
                 if (ret) {
                     RETURN_ON_ERROR(ret);
                     RETURN_SUCCESS;
@@ -1232,7 +1236,7 @@ dispatch:
             DATA_PUSH(&ctx->u.rep->last_ptr);
             ctx->u.rep->last_ptr = state->ptr;
             DO_JUMP(JUMP_MIN_UNTIL_3,jump_min_until_3,
-                    ctx->u.rep->pattern+4);
+                    ctx->u.rep->pattern+3);
             DATA_POP(&ctx->u.rep->last_ptr);
             if (ret) {
                 RETURN_ON_ERROR(ret);