RM_ZsetRem: Delete key if empty (#8453)

Without this fix, RM_ZsetRem can leave empty sorted sets which are
not allowed to exist.

Removing from a sorted set while iterating seems to work (while
inserting causes failed assetions). RM_ZsetRangeEndReached is
modified to return 1 if the key doesn't exist, to terminate
iteration when the last element has been removed.

(cherry picked from commit aea6e71ef8)
This commit is contained in:
Viktor Söderqvist 2021-02-05 18:54:01 +01:00 committed by Oran Agra
parent cde69883a1
commit 17c3ac89e7
5 changed files with 50 additions and 0 deletions

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@ -28,4 +28,5 @@ $TCLSH tests/test_helper.tcl \
--single unit/moduleapi/keyspace_events \
--single unit/moduleapi/blockedclient \
--single unit/moduleapi/getkeys \
--single unit/moduleapi/zset \
"${@}"

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@ -2508,6 +2508,7 @@ int RM_ZsetRem(RedisModuleKey *key, RedisModuleString *ele, int *deleted) {
if (key->value && key->value->type != OBJ_ZSET) return REDISMODULE_ERR;
if (key->value != NULL && zsetDel(key->value,ele->ptr)) {
if (deleted) *deleted = 1;
moduleDelKeyIfEmpty(key);
} else {
if (deleted) *deleted = 0;
}
@ -2552,6 +2553,7 @@ void RM_ZsetRangeStop(RedisModuleKey *key) {
/* Return the "End of range" flag value to signal the end of the iteration. */
int RM_ZsetRangeEndReached(RedisModuleKey *key) {
if (!key->value || key->value->type != OBJ_ZSET) return 1;
return key->zer;
}

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@ -25,6 +25,7 @@ TEST_MODULES = \
auth.so \
keyspace_events.so \
blockedclient.so \
zset.so \
getkeys.so

30
tests/modules/zset.c Normal file
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@ -0,0 +1,30 @@
#include "redismodule.h"
/* ZSET.REM key element
*
* Removes an occurrence of an element from a sorted set. Replies with the
* number of removed elements (0 or 1).
*/
int zset_rem(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) {
if (argc != 3) return RedisModule_WrongArity(ctx);
RedisModule_AutoMemory(ctx);
int keymode = REDISMODULE_READ | REDISMODULE_WRITE;
RedisModuleKey *key = RedisModule_OpenKey(ctx, argv[1], keymode);
int deleted;
if (RedisModule_ZsetRem(key, argv[2], &deleted) == REDISMODULE_OK)
return RedisModule_ReplyWithLongLong(ctx, deleted);
else
return RedisModule_ReplyWithError(ctx, "ERR ZsetRem failed");
}
int RedisModule_OnLoad(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) {
REDISMODULE_NOT_USED(argv);
REDISMODULE_NOT_USED(argc);
if (RedisModule_Init(ctx, "zset", 1, REDISMODULE_APIVER_1) ==
REDISMODULE_OK &&
RedisModule_CreateCommand(ctx, "zset.rem", zset_rem, "",
1, 1, 1) == REDISMODULE_OK)
return REDISMODULE_OK;
else
return REDISMODULE_ERR;
}

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@ -0,0 +1,16 @@
set testmodule [file normalize tests/modules/zset.so]
start_server {tags {"modules"}} {
r module load $testmodule
test {Module zset rem} {
r del k
r zadd k 100 hello 200 world
assert_equal 1 [r zset.rem k hello]
assert_equal 0 [r zset.rem k hello]
assert_equal 1 [r exists k]
# Check that removing the last element deletes the key
assert_equal 1 [r zset.rem k world]
assert_equal 0 [r exists k]
}
}