ICU-20471 setFormatWidth to 0 should cause padding to be ignored

icu4c/source/i18n/number_mapper.cpp

@@ -182,7 +182,7 @@ MacroProps NumberPropertyMapper::oldToNew(const DecimalFormatProperties& propert
     // PADDING //
     /////////////
 
-    if (properties.formatWidth != -1) {
+    if (properties.formatWidth > 0) {
         macros.padder = Padder::forProperties(properties);
     }
 

icu4c/source/i18n/number_patternstring.cpp

@@ -781,7 +781,7 @@ UnicodeString PatternStringUtils::propertiesToPatternString(const DecimalFormatP
     sb.append(affixes.getString(AffixPatternProvider::AFFIX_POS_SUFFIX));
 
     // Resolve Padding
-    if (paddingWidth != -1 && !paddingLocation.isNull()) {
+    if (paddingWidth > 0 && !paddingLocation.isNull()) {
         while (paddingWidth - sb.length() > 0) {
             sb.insert(afterPrefixPos, u'#');
             beforeSuffixPos++;

icu4c/source/test/cintltst/cnumtst.c

@@ -72,6 +72,7 @@ static void TestRBNFRounding(void);
 static void Test12052_NullPointer(void);
 static void TestParseCases(void);
 static void TestSetMaxFracAndRoundIncr(void);
+static void TestIgnorePadding(void);
 
 #define TESTCASE(x) addTest(root, &x, "tsformat/cnumtst/" #x)
 
@@ -110,6 +111,7 @@ void addNumForTest(TestNode** root)
     TESTCASE(Test12052_NullPointer);
     TESTCASE(TestParseCases);
     TESTCASE(TestSetMaxFracAndRoundIncr);
+    TESTCASE(TestIgnorePadding);
 }
 
 /* test Parse int 64 */
@@ -3386,4 +3388,52 @@ static void TestSetMaxFracAndRoundIncr(void) {
     }
 }
 
+static void TestIgnorePadding(void) {
+    UErrorCode status = U_ZERO_ERROR;
+    UNumberFormat* unum = unum_open(UNUM_PATTERN_DECIMAL, NULL, 0, "en_US", NULL, &status);
+    if (U_FAILURE(status)) {
+        log_data_err("unum_open UNUM_PATTERN_DECIMAL for en_US and NULL pattern fails:%s\n", u_errorName(status));
+    } else {
+        unum_setAttribute(unum, UNUM_GROUPING_USED, 0);
+        unum_setAttribute(unum, UNUM_FORMAT_WIDTH, 0);
+        unum_setTextAttribute(unum, UNUM_PADDING_CHARACTER, u"*", 1, &status);
+        if (U_FAILURE(status)) {
+            log_err("unum_setTextAttribute UNUM_PADDING_CHARACTER to '*' fails: %s\n", u_errorName(status));
+        } else {
+            unum_setAttribute(unum, UNUM_PADDING_POSITION, 0);
+            unum_setAttribute(unum, UNUM_MIN_INTEGER_DIGITS, 0);
+            unum_setAttribute(unum, UNUM_MAX_INTEGER_DIGITS, 8);
+            unum_setAttribute(unum, UNUM_MIN_FRACTION_DIGITS, 0);
+            unum_setAttribute(unum, UNUM_MAX_FRACTION_DIGITS, 0);
+
+            UChar ubuf[kUBufMax];
+            int32_t ulen = unum_toPattern(unum, FALSE, ubuf, kUBufMax, &status);
+            if (U_FAILURE(status)) {
+                log_err("unum_toPattern fails: %s\n", u_errorName(status));
+            } else {
+                char bbuf[kBBufMax];
+                if (ulen > 0 && ubuf[0]==u'*') {
+                    ubuf[kUBufMax-1] = 0; // ensure zero termination
+                    u_austrncpy(bbuf, ubuf, kBBufMax);
+                    log_err("unum_toPattern result should ignore padding but get %s\n", bbuf);
+                }
+                unum_applyPattern(unum, FALSE, ubuf, ulen, NULL, &status);
+                if (U_FAILURE(status)) {
+                    log_err("unum_applyPattern fails: %s\n", u_errorName(status));
+                } else {
+                    ulen = unum_formatDecimal(unum, "24", -1, ubuf, kUBufMax, NULL, &status);
+                    if (U_FAILURE(status)) {
+                        log_err("unum_formatDecimal fails: %s\n", u_errorName(status));
+                    } else if (u_strcmp(ubuf, u"24") != 0) {
+                        ubuf[kUBufMax-1] = 0; // ensure zero termination
+                        u_austrncpy(bbuf, ubuf, kBBufMax);
+                        log_err("unum_formatDecimal result expect 24 but get %s\n", bbuf);
+                    }
+                }
+            }
+        }
+        unum_close(unum);
+    }
+}
+
 #endif /* #if !UCONFIG_NO_FORMATTING */

icu4j/main/classes/core/src/com/ibm/icu/impl/number/PatternStringUtils.java

@@ -171,7 +171,7 @@ public class PatternStringUtils {
         sb.append(affixes.getString(AffixPatternProvider.FLAG_POS_SUFFIX));
 
         // Resolve Padding
-        if (paddingWidth != -1) {
+        if (paddingWidth > 0) {
             while (paddingWidth - sb.length() > 0) {
                 sb.insert(afterPrefixPos, '#');
                 beforeSuffixPos++;

icu4j/main/classes/core/src/com/ibm/icu/number/NumberPropertyMapper.java

@@ -219,7 +219,7 @@ final class NumberPropertyMapper {
         // PADDING //
         /////////////
 
-        if (properties.getFormatWidth() != -1) {
+        if (properties.getFormatWidth() > 0) {
             macros.padder = Padder.forProperties(properties);
         }
 

icu4j/main/tests/core/src/com/ibm/icu/dev/test/format/NumberFormatTest.java

@@ -1418,6 +1418,29 @@ public class NumberFormatTest extends TestFmwk {
         expect2(new DecimalFormat("*'😃'####.00", US), 1.1, "😃😃😃1.10");
     }
 
+    @Test
+    public void TestIgnorePadding() {
+        DecimalFormatSymbols dfs = new DecimalFormatSymbols(Locale.US);
+        DecimalFormat fmt = new DecimalFormat("", dfs);
+        fmt.setGroupingUsed(false);
+        fmt.setFormatWidth(0);
+        fmt.setPadCharacter('*');
+        fmt.setPadPosition(0);
+        fmt.setMinimumIntegerDigits(0);
+        fmt.setMaximumIntegerDigits(8);
+        fmt.setMinimumFractionDigits(0);
+        fmt.setMaximumFractionDigits(0);
+        String pattern = fmt.toPattern();
+        if (pattern.startsWith("*")) {
+            errln("ERROR toPattern result should ignore padding but get \"" + pattern + "\"");
+        }
+        fmt.applyPattern(pattern);
+        String format = fmt.format(24);
+        if (!format.equals("24")) {
+             errln("ERROR format result expect 24 but get \"" + format + "\"");
+       }
+    }
+
     /**
      * Upgrade to alphaWorks
      */