add callback function to properly report errors

Author: abhina-sree

llvm/lib/Support/CharSet.cpp

@@ -148,6 +148,12 @@ CharSetConverterICU::convertString(StringRef Source,
   Result.resize_for_overwrite(Capacity);
   char *Output = static_cast<char *>(Result.data());
   UErrorCode EC = U_ZERO_ERROR;
+
+  ucnv_setToUCallBack(&*FromConvDesc, UCNV_TO_U_CALLBACK_STOP, NULL, NULL, NULL,
+                      &EC);
+  ucnv_setToUCallBack(&*ToConvDesc, UCNV_TO_U_CALLBACK_STOP, NULL, NULL, NULL,
+                      &EC);
+
   do {
     EC = U_ZERO_ERROR;
     const char *Input = In;

llvm/unittests/Support/CharSetTest.cpp

@@ -50,6 +50,8 @@ static const char EarthISO2022[] =
     "\x45\x61\x72\x74\x68\x1B\x24\x42\x43\x4F\x35\x65\x1B\x28\x42";
 static const char EarthIBM939[] =
     "\xc5\x81\x99\xa3\x88\x0e\x45\xc2\x48\xdb\x0f";
+static const char EarthUTFExtraPartial[] =
+    "\x45\x61\x72\x74\x68\xe5\x9c\xb0\xe7\x90\x83\xe5";
 
 TEST(CharSet, FromUTF8) {
   // Hello string.
@@ -171,6 +173,25 @@ TEST(CharSet, ShiftState2022) {
   EXPECT_STREQ(EarthISO2022, static_cast<std::string>(Dst).c_str());
 }
 
+TEST(CharSet, ShiftState2022Partial) {
+  // Earth string.
+  StringRef Src(EarthUTFExtraPartial);
+  SmallString<8> Dst;
+
+  ErrorOr<CharSetConverter> ConvTo2022 =
+      CharSetConverter::create("UTF-8", "ISO-2022-JP");
+  // Stop test if conversion is not supported (no underlying iconv support).
+  if (!ConvTo2022) {
+    ASSERT_EQ(ConvTo2022.getError(),
+              std::make_error_code(std::errc::invalid_argument));
+    return;
+  }
+
+  // Check that the string is properly converted.
+  std::error_code EC = ConvTo2022->convert(Src, Dst);
+  EXPECT_TRUE(EC);
+}
+
 TEST(CharSet, ShiftStateIBM939) {
   // Earth string.
   StringRef Src(EarthUTF);