Do not forget to actually set newStr to an empty string

Change-Id: I745b09d8a248f08afdd3387f4cfcf69d71ec3c39

sal/qa/rtl/strings/test_strings_replace.cxx

@@ -20,6 +20,7 @@
 
 namespace {
 
+OUString s_empty;
 OUString s_bar("bar");
 OUString s_bars("bars");
 OUString s_foo("foo");
@@ -176,6 +177,9 @@ void Test::ustringReplaceFirstAsciiL() {
             rtl::OUString("foobarfoo").replaceFirst("bar", s_other, &n));
         CPPUNIT_ASSERT_EQUAL(sal_Int32(-1), n);
     }
+
+    CPPUNIT_ASSERT_EQUAL(
+        rtl::OUString(), rtl::OUString("xa").replaceFirst("xa", s_empty));
 }
 
 void Test::ustringReplaceFirstToAsciiL() {
@@ -210,6 +214,9 @@ void Test::ustringReplaceFirstToAsciiL() {
             rtl::OUString("foobarfoo").replaceFirst(s_bar, "other", &n));
         CPPUNIT_ASSERT_EQUAL(sal_Int32(-1), n);
     }
+
+    CPPUNIT_ASSERT_EQUAL(
+        rtl::OUString(), rtl::OUString("xa").replaceFirst(s_xa, ""));
 }
 
 void Test::ustringReplaceFirstAsciiLAsciiL() {
@@ -249,6 +256,9 @@ void Test::ustringReplaceFirstAsciiLAsciiL() {
              replaceFirst("bar", "other", &n)));
         CPPUNIT_ASSERT_EQUAL(sal_Int32(-1), n);
     }
+
+    CPPUNIT_ASSERT_EQUAL(
+        rtl::OUString(), rtl::OUString("xa").replaceFirst("xa", ""));
 }
 
 void Test::ustringReplaceAll() {
@@ -277,6 +287,9 @@ void Test::ustringReplaceAllAsciiL() {
     CPPUNIT_ASSERT_EQUAL(
         rtl::OUString("xxa"),
         rtl::OUString("xaa").replaceAll("xa", s_xx));
+
+    CPPUNIT_ASSERT_EQUAL(
+        rtl::OUString(), rtl::OUString("xa").replaceAll("xa", s_empty));
 }
 
 void Test::ustringReplaceAllToAsciiL() {
@@ -291,6 +304,9 @@ void Test::ustringReplaceAllToAsciiL() {
     CPPUNIT_ASSERT_EQUAL(
         rtl::OUString("xxa"),
         rtl::OUString("xaa").replaceAll(s_xa, "xx"));
+
+    CPPUNIT_ASSERT_EQUAL(
+        rtl::OUString(), rtl::OUString("xa").replaceAll(s_xa, ""));
 }
 
 void Test::ustringReplaceAllAsciiLAsciiL() {
@@ -308,6 +324,9 @@ void Test::ustringReplaceAllAsciiLAsciiL() {
         rtl::OUString("xxa"),
         (rtl::OUString("xaa").
          replaceAll("xa", "xx")));
+
+    CPPUNIT_ASSERT_EQUAL(
+        rtl::OUString(), rtl::OUString("xa").replaceAll("xa", ""));
 }
 
 }

sal/rtl/ustring.cxx

@@ -1154,8 +1154,8 @@ void rtl_uString_newReplaceFirstAsciiL(
         }
         sal_Int32 n = str->length - fromLength + to->length;
         rtl_uString_acquire(str); // in case *newStr == str
+        rtl_uString_new_WithLength(newStr, n);
         if (n != 0) {
-            rtl_uString_new_WithLength(newStr, n);
             (*newStr)->length = n;
             assert(i >= 0 && i < str->length);
             memcpy(
@@ -1196,8 +1196,8 @@ void rtl_uString_newReplaceFirstToAsciiL(
         }
         sal_Int32 n = str->length - from->length + toLength;
         rtl_uString_acquire(str); // in case *newStr == str
+        rtl_uString_new_WithLength(newStr, n);
         if (n != 0) {
-            rtl_uString_new_WithLength(newStr, n);
             (*newStr)->length = n;
             assert(i >= 0 && i < str->length);
             memcpy(
@@ -1240,8 +1240,8 @@ void rtl_uString_newReplaceFirstAsciiLAsciiL(
         }
         sal_Int32 n = str->length - fromLength + toLength;
         rtl_uString_acquire(str); // in case *newStr == str
+        rtl_uString_new_WithLength(newStr, n);
         if (n != 0) {
-            rtl_uString_new_WithLength(newStr, n);
             (*newStr)->length = n;
             assert(i >= 0 && i < str->length);
             memcpy(