PERF: remove redundant checks in HINCRBYFLOAT & INCREX commands

src/t_hash.c

@@ -1280,7 +1280,7 @@ void hincrbyfloatCommand(client *c) {
     mstime_t expiry = EXPIRY_NONE;
 
     if (getLongDoubleFromObjectOrReply(c, c->argv[3], &incr, NULL) != C_OK) return;
-    if (isnan(incr) || isinf(incr)) {
+    if (isinf(incr)) {
         addReplyError(c, "value is NaN or Infinity");
         return;
     }
@@ -1300,8 +1300,8 @@ void hincrbyfloatCommand(client *c) {
     }
 
     value += incr;
-    if (isnan(value) || isinf(value)) {
-        addReplyError(c, "increment would produce NaN or Infinity");
+    if (isinf(value)) {
+        addReplyError(c, "increment would produce Infinity");
         return;
     }
 

src/t_string.c

@@ -880,10 +880,6 @@ void increxCommand(client *c) {
             return;
         }
         value_ld = oldvalue_ld + incr_ld;
-        if (isnan(value_ld)) {
-            addReplyError(c, "Increment is not a valid float");
-            return;
-        }
         if (isinf(value_ld)) {
             addReplyArrayLen(c, 2);
             addReplyHumanLongDouble(c, oldvalue_ld);

tests/unit/type/hash.tcl

@@ -960,6 +960,21 @@ start_server {tags {"hash"}} {
         assert_error "*value is NaN or Infinity*" {r hincrbyfloat hfoo field +inf}
         assert_equal 0 [r exists hfoo]
     } {} {valgrind:skip}
+
+    test {HINCRBYFLOAT rejects a NaN increment} {
+        r del hfoo
+        assert_error "*value is not a valid float*" {r hincrbyfloat hfoo field nan}
+    }
+
+    test {HINCRBYFLOAT with an infinite field value} {
+        r del hfoo
+        r hset hfoo field inf
+        assert_error "*would produce Infinity*" {r hincrbyfloat hfoo field 1}
+        assert_equal inf [r hget hfoo field]
+        # An infinite increment is dropped before the result is ever computed.
+        assert_error "*value is NaN or Infinity*" {r hincrbyfloat hfoo field -inf}
+        assert_equal inf [r hget hfoo field]
+    } {} {valgrind:skip}
 }
 
 start_server {config "minimal.conf" tags {"hash" "external:skip"} overrides {io-threads 4 io-threads-always-active yes hash-max-listpack-entries 0}} {

tests/unit/type/incr.tcl

@@ -151,6 +151,17 @@ start_server {tags {"incr"}} {
             # perform divisions.
     } {ERR *would produce*} {valgrind:skip}
 
+    test {INCRBYFLOAT rejects a NaN increment} {
+        r set foo 0
+        assert_error "*value is not a valid float*" {r incrbyfloat foo nan}
+    }
+
+    test {INCRBYFLOAT with an infinite field value} {
+        r set foo inf
+        assert_error "*would produce NaN or Infinity*" {r incrbyfloat foo -inf}
+        assert_equal inf [r get foo]
+    } {} {valgrind:skip}
+
     test {INCRBYFLOAT decrement} {
         r set foo 1
         roundFloat [r incrbyfloat foo -1.1]