ld2string should fail if string contains \0 in the middle

This bug affected RM_StringToLongDouble and HINCRBYFLOAT.
I added tests for both cases.

Main changes:
1. Fixed string2ld to fail if string contains \0 in the middle
2. Use string2ld in getLongDoubleFromObject - No point of
   having duplicated code here

The two changes above broke RM_SaveLongDouble/RM_LoadLongDouble
because the long double string was saved with length+1 (An innocent
mistake, but it's actually a bug - The length passed to
RM_SaveLongDouble should not include the last \0).

1 files changed, 9 insertions, 0 deletions

diff --git a/tests/modules/misc.c b/tests/modules/misc.c
index b5a032f60..41bec06ed 100644
--- a/tests/modules/misc.c
+++ b/tests/modules/misc.c
@@ -74,6 +74,15 @@ int test_ld_conv(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) {
         RedisModule_ReplyWithError(ctx, err);
         goto final;
     }
+    /* Make sure we can't convert a string that has \0 in it */
+    char buf[4] = "123";
+    buf[1] = '\0';
+    RedisModuleString *s3 = RedisModule_CreateString(ctx, buf, 3);
+    long double ld3;
+    if (RedisModule_StringToLongDouble(s3, &ld3) == REDISMODULE_OK) {
+        RedisModule_ReplyWithError(ctx, "Invalid string successfully converted to long double");
+        goto final;
+    }
     RedisModule_ReplyWithLongDouble(ctx, ld2);
 final:
     RedisModule_FreeString(ctx, s1);