shiboken6/ConditionalStreamReader: Fix conditions that consists of exclusions only

<?if !nonexisting?> returned false since no matching keywords were
found.

Amends 77669e48fd8ac0f4ca199173672c4bf0c9dc654b.

Task-number: PYSIDE-802
Task-number: PYSIDE-1568
Change-Id: I586916a5aec68e515b708020028e824e23a58a57
Reviewed-by: Christian Tismer <tismer@stackless.com>

2 files changed, 12 insertions, 4 deletions

diff --git a/sources/shiboken6/ApiExtractor/conditionalstreamreader.cpp b/sources/shiboken6/ApiExtractor/conditionalstreamreader.cpp
index 2380ee892..c3c312eeb 100644
--- a/sources/shiboken6/ApiExtractor/conditionalstreamreader.cpp
+++ b/sources/shiboken6/ApiExtractor/conditionalstreamreader.cpp
@@ -57,17 +57,21 @@ QXmlStreamReader::TokenType ConditionalStreamReader::readNext()
 bool ConditionalStreamReader::conditionMatches() const
 {
     const auto keywords = m_reader.processingInstructionData().split(u' ', Qt::SkipEmptyParts);
+    if (keywords.isEmpty())
+        return false;
 
     bool matches = false;
+    bool exclusionOnly = true;
     for (const auto &keyword : keywords) {
         if (keyword.startsWith(u'!')) { // exclusion '!windows' takes preference
             if (m_conditions.contains(keyword.mid(1)))
                 return false;
         } else {
+            exclusionOnly = false;
             matches |= m_conditions.contains(keyword);
         }
     }
-    return matches;
+    return exclusionOnly || matches;
 }
 
 void ConditionalStreamReader::setConditions(const QStringList &newConditions)
diff --git a/sources/shiboken6/ApiExtractor/tests/testdroptypeentries.cpp b/sources/shiboken6/ApiExtractor/tests/testdroptypeentries.cpp
index 1b03f9353..d59c365dd 100644
--- a/sources/shiboken6/ApiExtractor/tests/testdroptypeentries.cpp
+++ b/sources/shiboken6/ApiExtractor/tests/testdroptypeentries.cpp
@@ -162,6 +162,9 @@ void TestDropTypeEntries::testConditionalParsing_data()
         <?endif?>
     <?endif?>
     <tag5>text</tag5>
+    <?if !keyword99?> <!-- Exclusion only -->
+        <tag6>text</tag6>
+    <?endif?>
 </root>)");
 
     const QString root = QStringLiteral("root");
@@ -170,6 +173,7 @@ void TestDropTypeEntries::testConditionalParsing_data()
     const QString tag3 = QStringLiteral("tag3");
     const QString tag4 = QStringLiteral("tag4");
     const QString tag5 = QStringLiteral("tag5");
+    const QString tag6 = QStringLiteral("tag6");
     const QString keyword1 = QStringLiteral("keyword1");
     const QString keyword2 = QStringLiteral("keyword2");
 
@@ -178,15 +182,15 @@ void TestDropTypeEntries::testConditionalParsing_data()
     QTest::addColumn<QStringList>("expectedTags");
 
     QTest::newRow("no-keywords")
-        << xml << QStringList{} << QStringList{root, tag1, tag5};
+        << xml << QStringList{} << QStringList{root, tag1, tag5, tag6};
 
     QTest::newRow("skip-nested-condition")
         << xml << QStringList{keyword1}
-        << QStringList{root, tag1, tag2, tag4, tag5};
+        << QStringList{root, tag1, tag2, tag4, tag5, tag6};
 
     QTest::newRow("both/check-not")
         << xml << QStringList{keyword1, keyword2}
-        << QStringList{root, tag1, tag2, tag3, tag5};
+        << QStringList{root, tag1, tag2, tag3, tag5, tag6};
 }
 
 // Parse XML and return a list of tags encountered