Utils: Add combine with device env option

Adds the option Environment::combineWithDeviceEnvironment. This allows
the linuxdevice to set it to false.

Without this option a deadlock would occur when the QtcProcess tries to
get the device environment and the device shell failed to start.
(e.g. because a required command is missing on the device).

Change-Id: I8f7550d0d90e989a339f27e993a836e67e910e33
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>
Reviewed-by: hjk <hjk@qt.io>

src/libs/utils/environment.h

@@ -81,6 +81,9 @@ public:
     QString value(const_iterator it) const { return m_dict.value(it); } // FIXME: avoid
     bool isEnabled(const_iterator it) const { return m_dict.isEnabled(it); } // FIXME: avoid
 
+    void setCombineWithDeviceEnvironment(bool combine) { m_combineWithDeviceEnvironment = combine; }
+    bool combineWithDeviceEnvironment() const { return m_combineWithDeviceEnvironment; }
+
     const_iterator constBegin() const { return m_dict.constBegin(); } // FIXME: avoid
     const_iterator constEnd() const { return m_dict.constEnd(); } // FIXME: avoid
     const_iterator constFind(const QString &name) const { return m_dict.constFind(name); } // FIXME: avoid
@@ -102,6 +105,7 @@ public:
 
 private:
     NameValueDictionary m_dict;
+    bool m_combineWithDeviceEnvironment = true;
 };
 
 class QTCREATOR_UTILS_EXPORT EnvironmentChange final

src/libs/utils/qtcprocess.cpp

@@ -670,7 +670,7 @@ public:
     Environment fullEnvironment() const
     {
         Environment env = m_setup.m_environment;
-        if (!env.hasChanges()) {
+        if (!env.hasChanges() && env.combineWithDeviceEnvironment()) {
             // FIXME: Either switch to using EnvironmentChange instead of full Environments, or
             // feed the full environment into the QtcProcess instead of fixing it up here.
             //            qWarning("QtcProcess::start: Empty environment set when running '%s'.",

src/plugins/remotelinux/linuxdevice.cpp

@@ -359,6 +359,8 @@ public:
     RunResult runInShell(const CommandLine &cmdLine,
                          const QByteArray &stdInData) const override;
 
+    Environment deviceEnvironment() const override;
+
     LinuxDevicePrivate *m_dev;
 };
 
@@ -388,6 +390,19 @@ RunResult LinuxDeviceFileAccess::runInShell(const CommandLine &cmdLine,
     return m_dev->runInShell(cmdLine, stdInData);
 }
 
+Environment LinuxDeviceFileAccess::deviceEnvironment() const
+{
+    QtcProcess getEnvProc;
+    getEnvProc.setCommand({FilePath("env").onDevice(m_dev->q->rootPath()), {}});
+    Environment inEnv;
+    inEnv.setCombineWithDeviceEnvironment(false);
+    getEnvProc.setEnvironment(inEnv);
+    getEnvProc.runBlocking();
+
+    const QString remoteOutput = getEnvProc.cleanedStdOut();
+    return Environment(remoteOutput.split('\n', Qt::SkipEmptyParts), m_dev->q->osType());
+}
+
 // SshProcessImpl
 
 class SshProcessInterfacePrivate : public QObject