QLocale: Have qstrntod() return end of parsed string also on underflow

Underflows should be treated the same as overflows.

Fixes: QTBUG-108628
Change-Id: I23aa7bbe1d103778cefca08bd3e584e72f306583
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>

2 files changed, 9 insertions, 1 deletions

diff --git a/src/corelib/text/qlocale_tools.cpp b/src/corelib/text/qlocale_tools.cpp
index ac4c870802..a123714f7f 100644
--- a/src/corelib/text/qlocale_tools.cpp
+++ b/src/corelib/text/qlocale_tools.cpp
@@ -354,7 +354,7 @@ QSimpleParsedNumber<double> qt_asciiToDouble(const char *num, qsizetype numLen,
         for (int i = 0; i < processed; ++i) {
             if (num[i] >= '1' && num[i] <= '9') {
                 // if a digit before any 'e' is not 0, then a non-zero number was intended.
-                return {};
+                return {d, -processed};
             } else if (num[i] == 'e' || num[i] == 'E') {
                 break;
             }
diff --git a/tests/auto/corelib/text/qlocale/tst_qlocale.cpp b/tests/auto/corelib/text/qlocale/tst_qlocale.cpp
index 593b98dd60..11da627bd0 100644
--- a/tests/auto/corelib/text/qlocale/tst_qlocale.cpp
+++ b/tests/auto/corelib/text/qlocale/tst_qlocale.cpp
@@ -1250,6 +1250,10 @@ void tst_QLocale::strtod_data()
     QTest::newRow("1e2000")          << QString("1e2000")          << qInf()        << 6  << false;
     QTest::newRow("-1e2000")         << QString("-1e2000")         << -qInf()       << 7  << false;
 
+    // Underflow - fails but reports right length:
+    QTest::newRow("1e-2000")         << QString("1e-2000")         << 0.0           << 7  << false;
+    QTest::newRow("-1e-2000")        << QString("-1e-2000")        << 0.0           << 8  << false;
+
     // starts with junk, fails
     QTest::newRow("a0")               << QString("a0")               << 0.0 << 0 << false;
     QTest::newRow("a0.")              << QString("a0.")              << 0.0 << 0 << false;
@@ -1285,6 +1289,10 @@ void tst_QLocale::strtod_data()
     QTest::newRow("1e2000 cruft")     << QString("1e2000 cruft")     << qInf()        << 6  << false;
     QTest::newRow("-1e2000 cruft")    << QString("-1e2000 cruft")    << -qInf()       << 7  << false;
 
+    // Underflow, ends with cruft - fails but reports right length:
+    QTest::newRow("1e-2000 cruft")    << QString("1e-2000 cruft")    << 0.0           << 7  << false;
+    QTest::newRow("-1e-2000 cruft")   << QString("-1e-2000 cruft")   << 0.0           << 8  << false;
+
     // "0x" prefix, success but only for the "0" before "x"
     QTest::newRow("0x0")               << QString("0x0")               << 0.0 << 1 << true;
     QTest::newRow("0x0.")              << QString("0x0.")              << 0.0 << 1 << true;