qmake: require a drive in a DOS path for it to be absolute

For Q_OS_WIN, a path is only truly absolute if it includes a drive
letter; merely starting with a slash is not enough.  (We can't support
UNC paths, so don't even try: qmake runs various commands in the
source directory using CMD.exe, which doesn't support UNC as PWD.)
This requires, when resolving a path relative to a root, transcribing
the root's drive to such not-quite-absolute paths.

Changed QMakeGlobals, $$absolute_path() and $$relative_path() to now
use IoUtils::resolvePath() rather than delegating to QDir's absolute
path method, since that doesn't correctly recognize the need for a
drive letter (and qmake did run into problems with some paths, from
splitPathList and a failing test, as a result).

Moved existing ioUtils tests for handling of relative / absolute paths
out into separate functions and expanded significantly.  Fixed some
existing tests to use an absolute path where one is needed; added two
tests involving driveless (but rooted) paths; and fixed the test init
to set a value for QT_HOST_DATA/src property (the lack of which lead
to an assertion failure with this fix).

Task-number: QTBUG-50839
Change-Id: I2bfc13c1bfbe1ae09997274622ea55cb3de31b43
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@qt.io>

1 files changed, 7 insertions, 6 deletions

diff --git a/qmake/library/qmakebuiltins.cpp b/qmake/library/qmakebuiltins.cpp
index 1b98cbd909..e4b00a6cb3 100644
--- a/qmake/library/qmakebuiltins.cpp
+++ b/qmake/library/qmakebuiltins.cpp
@@ -1173,9 +1173,9 @@ QMakeEvaluator::VisitReturn QMakeEvaluator::evaluateBuiltinExpand(
         if (args.count() > 2) {
             evalError(fL1S("absolute_path(path[, base]) requires one or two arguments."));
         } else {
-            QString rstr = QDir::cleanPath(
-                    QDir(args.count() > 1 ? args.at(1).toQString(m_tmp2) : currentDirectory())
-                    .absoluteFilePath(args.at(0).toQString(m_tmp1)));
+            QString arg = args.at(0).toQString(m_tmp1);
+            QString baseDir = args.count() > 1 ? args.at(1).toQString(m_tmp2) : currentDirectory();
+            QString rstr = arg.isEmpty() ? baseDir : IoUtils::resolvePath(baseDir, arg);
             ret << (rstr.isSharedWith(m_tmp1)
                         ? args.at(0)
                         : args.count() > 1 && rstr.isSharedWith(m_tmp2)
@@ -1187,9 +1187,10 @@ QMakeEvaluator::VisitReturn QMakeEvaluator::evaluateBuiltinExpand(
         if (args.count() > 2) {
             evalError(fL1S("relative_path(path[, base]) requires one or two arguments."));
         } else {
-            QDir baseDir(args.count() > 1 ? args.at(1).toQString(m_tmp2) : currentDirectory());
-            QString rstr = baseDir.relativeFilePath(baseDir.absoluteFilePath(
-                                args.at(0).toQString(m_tmp1)));
+            QString arg = args.at(0).toQString(m_tmp1);
+            QString baseDir = args.count() > 1 ? args.at(1).toQString(m_tmp2) : currentDirectory();
+            QString absArg = arg.isEmpty() ? baseDir : IoUtils::resolvePath(baseDir, arg);
+            QString rstr = QDir(baseDir).relativeFilePath(absArg);
             ret << (rstr.isSharedWith(m_tmp1) ? args.at(0) : ProString(rstr).setSource(args.at(0)));
         }
         break;