Python: detect virtual environments for documents and projects

After opening a document or project the directory hierarchy is looked up
for a Scripts/(activate && python.exe) on windows or bin/(activate &&
python) on unix. This is the usual structure of python virtual
environments. If such a folder is found add the python from that folder
to the list of configured interpreters in the settings, set it as the
current interpreter for the project and try to open the corresponding
language server.

Change-Id: I038c309ea2988f9370194330d250d1515beac0a0
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/plugins/python/pythonrunconfiguration.cpp

@@ -260,8 +260,10 @@ PythonRunConfiguration::PythonRunConfiguration(Target *target, Core::Id id)
     connect(PythonSettings::instance(), &PythonSettings::interpretersChanged,
             interpreterAspect, &InterpreterAspect::updateInterpreters);
 
-    interpreterAspect->updateInterpreters(PythonSettings::interpreters());
-    interpreterAspect->setDefaultInterpreter(PythonSettings::defaultInterpreter());
+    QList<Interpreter> interpreters = PythonSettings::detectPythonVenvs(project()->projectDirectory());
+    aspect<InterpreterAspect>()->updateInterpreters(PythonSettings::interpreters());
+    aspect<InterpreterAspect>()->setDefaultInterpreter(
+        interpreters.isEmpty() ? PythonSettings::defaultInterpreter() : interpreters.first());
 
     auto scriptAspect = addAspect<MainScriptAspect>();
     scriptAspect->setSettingsKey("PythonEditor.RunConfiguation.Script");

src/plugins/python/pythonsettings.cpp

@@ -211,6 +211,7 @@ public:
     InterpreterOptionsPage();
 
     void setInterpreter(const QList<Interpreter> &interpreters) { m_interpreters = interpreters; }
+    void addInterpreter(const Interpreter &interpreter) { m_interpreters << interpreter; }
     QList<Interpreter> interpreters() const { return m_interpreters; }
     void setDefaultInterpreter(const QString &defaultId)
     { m_defaultInterpreterId = defaultId; }
@@ -278,6 +279,7 @@ Interpreter::Interpreter(const FilePath &python, const QString &defaultName, boo
 {
     SynchronousProcess pythonProcess;
     pythonProcess.setProcessChannelMode(QProcess::MergedChannels);
+    pythonProcess.setTimeoutS(1);
     SynchronousProcessResponse response = pythonProcess.runBlocking(
         CommandLine(python, {"--version"}));
     if (response.result == SynchronousProcessResponse::Finished)
@@ -467,9 +469,15 @@ void PythonSettings::setInterpreter(const QList<Interpreter> &interpreters, cons
 {
     interpreterOptionsPage().setInterpreter(interpreters);
     interpreterOptionsPage().setDefaultInterpreter(defaultId);
-    toSettings(Core::ICore::settings(), {interpreters, defaultId});
-    if (QTC_GUARD(settingsInstance))
-        emit settingsInstance->interpretersChanged(interpreters, defaultId);
+    saveSettings();
+}
+
+void PythonSettings::addInterpreter(const Interpreter &interpreter, bool isDefault)
+{
+    interpreterOptionsPage().addInterpreter(interpreter);
+    if (isDefault)
+        interpreterOptionsPage().setDefaultInterpreter(interpreter.id);
+    saveSettings();
 }
 
 PythonSettings *PythonSettings::instance()
@@ -478,6 +486,52 @@ PythonSettings *PythonSettings::instance()
     return settingsInstance;
 }
 
+QList<Interpreter> PythonSettings::detectPythonVenvs(const FilePath &path)
+{
+    QList<Interpreter> result;
+    QDir dir = path.toFileInfo().isDir() ? QDir(path.toString()) : path.toFileInfo().dir();
+    if (dir.exists()) {
+        const QString venvPython = HostOsInfo::withExecutableSuffix("python");
+        const QString activatePath = HostOsInfo::isWindowsHost() ? QString{"Scripts"}
+                                                                 : QString{"bin"};
+        do {
+            for (const QString &directory : dir.entryList(QDir::Dirs | QDir::NoDotAndDotDot)) {
+                if (dir.cd(directory)) {
+                    if (dir.cd(activatePath)) {
+                        if (dir.exists("activate") && dir.exists(venvPython)) {
+                            FilePath python = FilePath::fromString(dir.absoluteFilePath(venvPython));
+                            dir.cdUp();
+                            const QString defaultName = QString("Python (%1 Virtual Environment)")
+                                                            .arg(dir.dirName());
+                            Interpreter interpreter
+                                = Utils::findOrDefault(PythonSettings::interpreters(),
+                                                       Utils::equal(&Interpreter::command, python));
+                            if (interpreter.command.isEmpty()) {
+                                interpreter = Interpreter(python, defaultName);
+                                PythonSettings::addInterpreter(interpreter);
+                            }
+                            result << interpreter;
+                        } else {
+                            dir.cdUp();
+                        }
+                    }
+                    dir.cdUp();
+                }
+            }
+        } while (dir.cdUp());
+    }
+    return result;
+}
+
+void PythonSettings::saveSettings()
+{
+    const QList<Interpreter> &interpreters = interpreterOptionsPage().interpreters();
+    const QString &defaultId = interpreterOptionsPage().defaultInterpreter().id;
+    toSettings(Core::ICore::settings(), {interpreters, defaultId});
+    if (QTC_GUARD(settingsInstance))
+        emit settingsInstance->interpretersChanged(interpreters, defaultId);
+}
+
 QList<Interpreter> PythonSettings::interpreters()
 {
     return interpreterOptionsPage().interpreters();

src/plugins/python/pythonsettings.h

@@ -26,6 +26,7 @@
 #pragma once
 
 #include <utils/fileutils.h>
+#include <utils/optional.h>
 
 #include <QUuid>
 
@@ -57,13 +58,18 @@ public:
     static QList<Interpreter> interpreters();
     static Interpreter defaultInterpreter();
     static void setInterpreter(const QList<Interpreter> &interpreters, const QString &defaultId);
+    static void addInterpreter(const Interpreter &interpreter, bool isDefault = false);
     static PythonSettings *instance();
 
+    static QList<Interpreter> detectPythonVenvs(const Utils::FilePath &path);
+
 signals:
     void interpretersChanged(const QList<Interpreter> &interpreters, const QString &defaultId);
 
 private:
     PythonSettings();
+
+    static void saveSettings();
 };
 
 } // namespace Internal

src/plugins/python/pythonutils.cpp

@@ -175,6 +175,11 @@ static FilePath detectPython(const FilePath &documentPath)
         }
     }
 
+    // check whether this file is inside a python virtual environment
+    QList<Interpreter> venvInterpreters = PythonSettings::detectPythonVenvs(documentPath);
+    if (!python.exists())
+        python = venvInterpreters.value(0).command;
+
     if (!python.exists())
         python = PythonSettings::defaultInterpreter().command;
 
@@ -248,7 +253,13 @@ public:
                                          ? QString{"python-language-server[pyflakes]"}
                                          : QString{"python-language-server[all]"};
 
-        m_process.start(m_python.toString(), {"-m", "pip", "install", "--user", pylsVersion});
+        QStringList arguments = {"-m", "pip", "install", pylsVersion};
+
+        // add --user to global pythons, but skip it for venv pythons
+        if (!QDir(m_python.parentDir().toString()).exists("activate"))
+            arguments << "--user";
+
+        m_process.start(m_python.toString(), arguments);
 
         Core::MessageManager::write(tr("Running \"%1 %2\" to install Python language server")
                                         .arg(m_process.program(), m_process.arguments().join(' ')));