QValidator: return State::Intermediate for certain trailing characters

E.g. a group separator, a -/+ sign, or 'e' (exponent). Input ending with
one of these characters now returns Intermediate, as it can become
Acceptable if the user types more characters.

Remove a check from initialResultCheck(), as it's now covered by
QLocaleData::validateChars() checking that the last character in the
buffer is -/+, this works the same if buffer's size is 1.

Extended unittests based on the linked bug report; the other cases for
"last" are already covered by existing unittests.

Task-number: QTBUG-111371
Change-Id: I9b6979c29f07a5f57b040004cd3dbf4e27147c21
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>

src/corelib/text/qlocale.cpp

@@ -4297,6 +4297,12 @@ QLocaleData::validateChars(QStringView str, NumberMode numMode, int decDigits,
     }
 
     result.state = ParsingResult::Acceptable;
+
+    // Intermediate if it ends with any character that requires a digit after
+    // it to be valid e.g. group separator, sign, or exponent
+    if (last == ',' || last == '-' || last == '+' || last == 'e')
+        result.state = ParsingResult::Intermediate;
+
     return result;
 }
 

src/gui/util/qvalidator.cpp

@@ -377,9 +377,6 @@ std::optional<QValidator::State> initialResultCheck(T min, T max, const ParsingR
     if (signConflicts)
         return QValidator::Invalid;
 
-    if (buff.size() == 1 && (ch == '-' || ch == '+'))
-        return QValidator::Intermediate;
-
     if (result.state == ParsingResult::Intermediate)
         return QValidator::Intermediate;
 

tests/auto/gui/util/qintvalidator/tst_qintvalidator.cpp

@@ -167,7 +167,8 @@ void tst_QIntValidator::validateFrench()
     int i;
     // Grouping separator is a narrow no-break space; QLocale accepts a space as it.
     QString s = QLatin1String("1 ");
-    QCOMPARE(validator.validate(s, i), QValidator::Acceptable);
+    // Shouldn't end with a group separator
+    QCOMPARE(validator.validate(s, i), QValidator::Intermediate);
     validator.fixup(s);
     QCOMPARE(s, s);