fixed empty string case

Author: Kishan-Ved

integration_tests/test_str_01.py

@@ -115,7 +115,10 @@ def test_str_split():
     # assert res6 == [""]
 
 def test_str_replace():
+    x: str = "abc"
     a: str = "zzaaabracadabra"
+    print(x.replace("", ","))
+    print(a.replace("a",""))
     print(a.replace("",""))
     print(a.replace("a","b"))
     print(a.replace("e","a")) 
@@ -136,6 +139,7 @@ def test_str_replace():
     print(a.replace("b","k",1))
     print(a.replace("b","k",2))
     print(a.replace("zza","yo",2))
+    assert a.replace("a","") == "zzbrcdbr"
     assert a.replace("","") == "zzaaabracadabra"
     assert a.replace("a","b") == "zzbbbbrbcbdbbrb"
     assert a.replace("e","a") == "zzaaabracadabra"
@@ -156,6 +160,8 @@ def test_str_replace():
     assert a.replace("b","k",1) == "zzaaakracadabra"
     assert a.replace("b","k",2) == "zzaaakracadakra"
     assert a.replace("zza","yo",2) == "yoaabracadabra"
+    assert x.replace("", ",") == ",a,b,c,"
+
 
 def check():
     f()

src/runtime/lpython_builtin.py

@@ -917,12 +917,6 @@ def _lpython_str_split(x: str, sep:str) -> list[str]:
 
 @overload
 def _lpython_str_replace(x: str, old:str, new:str) -> str:
-    if (old == ""):
-        res: str = ""
-        i: str
-        for i in x:
-            res += new + i
-        return res
     return _lpython_str_replace(x, old, new, len(x))
 
 
@@ -933,7 +927,7 @@ def _lpython_str_replace(x: str, old:str, new:str, count: i32) -> str:
         s: str
         for s in x:
             res1 += new + s
-        return res1
+        return res1 + new
     res: str = ""
     i: i32 = 0
     ind: i32 = -1