Use python isolate mode

This (more or less) avoids user's environment variables tampering the
search process.
And also remove usages of `eval()` and `exec()`.

PR #18995.

src/base/search/searchdownloadhandler.cpp

@@ -46,6 +46,7 @@ SearchDownloadHandler::SearchDownloadHandler(const QString &siteUrl, const QStri
             , this, &SearchDownloadHandler::downloadProcessFinished);
     const QStringList params
     {
+        Utils::ForeignApps::PYTHON_ISOLATE_MODE_FLAG,
         (SearchPluginManager::engineLocation() / Path(u"nova2dl.py"_qs)).toString(),
         siteUrl,
         url

src/base/search/searchhandler.cpp

@@ -73,6 +73,7 @@ SearchHandler::SearchHandler(const QString &pattern, const QString &category, co
 
     const QStringList params
     {
+        Utils::ForeignApps::PYTHON_ISOLATE_MODE_FLAG,
         (SearchPluginManager::engineLocation() / Path(u"nova2.py"_qs)).toString(),
         m_usedPlugins.join(u','),
         m_category

src/base/search/searchpluginmanager.cpp

@@ -509,7 +509,12 @@ void SearchPluginManager::update()
     QProcess nova;
     nova.setProcessEnvironment(QProcessEnvironment::systemEnvironment());
 
-    const QStringList params {(engineLocation() / Path(u"/nova2.py"_qs)).toString(), u"--capabilities"_qs};
+    const QStringList params
+    {
+        Utils::ForeignApps::PYTHON_ISOLATE_MODE_FLAG,
+        (engineLocation() / Path(u"/nova2.py"_qs)).toString(),
+        u"--capabilities"_qs
+    };
     nova.start(Utils::ForeignApps::pythonInfo().executableName, params, QIODevice::ReadOnly);
     nova.waitForFinished();
 

src/base/utils/foreignapps.h

@@ -31,10 +31,13 @@
 
 #include <QString>
 
+#include "base/global.h"
 #include "base/utils/version.h"
 
 namespace Utils::ForeignApps
 {
+    inline const QString PYTHON_ISOLATE_MODE_FLAG = u"-I"_qs;
+
     struct PythonInfo
     {
         using Version = Utils::Version<3, 1>;

src/searchengine/nova3/nova2.py

@@ -1,4 +1,4 @@
-#VERSION: 1.43
+#VERSION: 1.44
 
 # Author:
 #  Fabien Devaux <fab AT gnux DOT info>
@@ -33,11 +33,13 @@
 # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 # POSSIBILITY OF SUCH DAMAGE.
 
+import importlib
+import pathlib
+import sys
 import urllib.parse
-from os import path
 from glob import glob
-from sys import argv
 from multiprocessing import Pool, cpu_count
+from os import path
 
 THREADED = True
 try:
@@ -70,9 +72,7 @@ def initialize_engines():
             continue
         try:
             # import engines.[engine]
-            engine_module = __import__(".".join(("engines", engi)))
-            # get low-level module
-            engine_module = getattr(engine_module, engi)
+            engine_module = importlib.import_module("engines." + engi)
             # bind class name
             globals()[engi] = getattr(engine_module, engi)
             supported_engines.append(engi)
@@ -143,6 +143,11 @@ def run_search(engine_list):
 
 
 def main(args):
+    # qbt tend to run this script in 'isolate mode' so append the current path manually
+    current_path = str(pathlib.Path(__file__).parent.resolve())
+    if current_path not in sys.path:
+        sys.path.append(current_path)
+
     supported_engines = initialize_engines()
 
     if not args:
@@ -187,4 +192,4 @@ def main(args):
 
 
 if __name__ == "__main__":
-    main(argv[1:])
+    main(sys.argv[1:])

src/searchengine/nova3/nova2dl.py

@@ -1,4 +1,4 @@
-#VERSION: 1.22
+#VERSION: 1.23
 
 # Author:
 #  Christophe DUMEZ (chris@qbittorrent.org)
@@ -27,9 +27,17 @@
 # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 # POSSIBILITY OF SUCH DAMAGE.
 
-import sys
-import os
 import glob
+import importlib
+import os
+import pathlib
+import sys
+
+# qbt tend to run this script in 'isolate mode' so append the current path manually
+current_path = str(pathlib.Path(__file__).parent.resolve())
+if current_path not in sys.path:
+    sys.path.append(current_path)
+
 from helpers import download_file
 
 supported_engines = dict()
@@ -42,8 +50,10 @@ for engine in engines:
     if e.startswith('_'):
         continue
     try:
-        exec("from engines.%s import %s" % (e, e))
-        exec("engine_url = %s.url" % e)
+        module = importlib.import_module("engines." + e)
+        engine_class = getattr(module, e)
+        globals()[e] = engine_class
+        engine_url = getattr(engine_class, 'url')
         supported_engines[engine_url] = e
     except Exception:
         pass
@@ -53,9 +63,9 @@ if __name__ == '__main__':
         raise SystemExit('./nova2dl.py engine_url download_parameter')
     engine_url = sys.argv[1].strip()
     download_param = sys.argv[2].strip()
-    if engine_url not in list(supported_engines.keys()):
+    if engine_url not in supported_engines.keys():
         raise SystemExit('./nova2dl.py: this engine_url was not recognized')
-    exec("engine = %s()" % supported_engines[engine_url])
+    engine = globals()[supported_engines[engine_url]]()
     if hasattr(engine, 'download_torrent'):
         engine.download_torrent(download_param)
     else: