Replace division by zero with +-inf

Author: tobiasdiez

src/sage/rings/integer.pyx

@@ -7755,9 +7755,9 @@ cdef double mpz_get_d_nearest(mpz_t x) except? -648555075988944.5:
     # Check for overflow
     if sx > 1024:
         if resultsign < 0:
-            return -1.0/0.0
+            return float('-inf')
         else:
-            return 1.0/0.0
+            return float('inf')
 
     # General case
 

src/sage/rings/rational.pyx

@@ -3993,9 +3993,9 @@ cdef double mpq_get_d_nearest(mpq_t x) except? -648555075988944.5:
             return 0.0
     elif shift >= 971:  # |d| > 2^1024
         if resultsign < 0:
-            return -1.0/0.0
+            return float('-inf')
         else:
-            return 1.0/0.0
+            return float('inf')
 
     sig_on()