From d7a6b3c01ed9242c21ed23436be3a6c45d54fd3f Mon Sep 17 00:00:00 2001
From: Frank Tang <ftang@chromium.org>
Date: Mon, 6 Nov 2023 12:43:03 -0800
Subject: [PATCH] ICU-22568 return TimeZomeFormat::createInstance for bogus
 locale

---
 icu4c/source/i18n/tzfmt.cpp             |  9 +++++----
 icu4c/source/test/intltest/tzfmttst.cpp | 11 +++++++++++
 icu4c/source/test/intltest/tzfmttst.h   |  1 +
 3 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/icu4c/source/i18n/tzfmt.cpp b/icu4c/source/i18n/tzfmt.cpp
index ed53438c4144..6891d3515f19 100644
--- a/icu4c/source/i18n/tzfmt.cpp
+++ b/icu4c/source/i18n/tzfmt.cpp
@@ -327,17 +327,18 @@ TimeZoneFormat::TimeZoneFormat(const Locale& locale, UErrorCode& status)
     const char* region = fLocale.getCountry();
     int32_t regionLen = static_cast<int32_t>(uprv_strlen(region));
     if (regionLen == 0) {
+        UErrorCode tempStatus = U_ZERO_ERROR;
         CharString loc;
         {
             CharStringByteSink sink(&loc);
-            ulocimp_addLikelySubtags(fLocale.getName(), sink, &status);
+            ulocimp_addLikelySubtags(fLocale.getName(), sink, &tempStatus);
         }
 
-        regionLen = uloc_getCountry(loc.data(), fTargetRegion, sizeof(fTargetRegion), &status);
-        if (U_SUCCESS(status)) {
+        regionLen = uloc_getCountry(loc.data(), fTargetRegion, sizeof(fTargetRegion), &tempStatus);
+        if (U_SUCCESS(tempStatus)) {
             fTargetRegion[regionLen] = 0;
         } else {
-            return;
+            fTargetRegion[0] = 0;
         }
     } else if (regionLen < (int32_t)sizeof(fTargetRegion)) {
         uprv_strcpy(fTargetRegion, region);
diff --git a/icu4c/source/test/intltest/tzfmttst.cpp b/icu4c/source/test/intltest/tzfmttst.cpp
index db79fc8a3d88..40a9b52c18a8 100644
--- a/icu4c/source/test/intltest/tzfmttst.cpp
+++ b/icu4c/source/test/intltest/tzfmttst.cpp
@@ -87,6 +87,7 @@ TimeZoneFormatTest::runIndexedTest( int32_t index, UBool exec, const char* &name
         TESTCASE(7, TestFormatTZDBNamesAllZoneCoverage);
         TESTCASE(8, TestAdoptDefaultThreadSafe);
         TESTCASE(9, TestCentralTime);
+        TESTCASE(10, TestBogusLocale);
     default: name = ""; break;
     }
 }
@@ -1402,4 +1403,14 @@ TimeZoneFormatTest::TestCentralTime() {
         }
     }
 }
+void
+TimeZoneFormatTest::TestBogusLocale() {
+    Locale bogus("not a lang");
+    UErrorCode status = U_ZERO_ERROR;
+    std::unique_ptr<icu::TimeZoneFormat> tzfmt(
+        icu::TimeZoneFormat::createInstance(bogus, status));
+    if (U_FAILURE(status)) {
+        errln(u"Failed to createInstance with bogus locale");
+    }
+}
 #endif /* #if !UCONFIG_NO_FORMATTING */
diff --git a/icu4c/source/test/intltest/tzfmttst.h b/icu4c/source/test/intltest/tzfmttst.h
index 8bbf5bc2b561..272b2b7832b0 100644
--- a/icu4c/source/test/intltest/tzfmttst.h
+++ b/icu4c/source/test/intltest/tzfmttst.h
@@ -31,6 +31,7 @@ class TimeZoneFormatTest : public IntlTest {
     void TestFormatTZDBNamesAllZoneCoverage();
     void TestAdoptDefaultThreadSafe();
     void TestCentralTime();
+    void TestBogusLocale();
 
     void RunTimeRoundTripTests(int32_t threadNumber);
     void RunAdoptDefaultThreadSafeTests(int32_t threadNumber);