Docker: Correct environment for docker exec calls

Provide way to clean QtcProcess environment which is needed as
e.g. toolchains, build tools, and debugger otherwise run
inside a wrong environment when using docker exec for the
respective process calls.

Change-Id: Ia6de1c90f2134fce260d293a2f6937ab3cfca2ce
Reviewed-by: hjk <hjk@qt.io>

src/libs/utils/qtcprocess.cpp

@@ -259,6 +259,12 @@ void QtcProcess::setEnvironment(const Environment &env)
     d->m_haveEnv = true;
 }
 
+void QtcProcess::unsetEnvironment()
+{
+    d->m_environment = Environment();
+    d->m_haveEnv = false;
+}
+
 const Environment &QtcProcess::environment() const
 {
     return d->m_environment;

src/libs/utils/qtcprocess.h

@@ -80,6 +80,7 @@ public:
     };
 
     void setEnvironment(const Environment &env);
+    void unsetEnvironment();
     const Environment &environment() const;
 
     void setCommand(const CommandLine &cmdLine);

src/plugins/docker/dockerdevice.cpp

@@ -1396,12 +1396,24 @@ void DockerDevice::runProcess(QtcProcess &process) const
 
     const FilePath workingDir = process.workingDirectory();
     const CommandLine origCmd = process.commandLine();
+    const Environment env = process.environment();
 
     CommandLine cmd{"docker", {"exec"}};
     if (!workingDir.isEmpty())
         cmd.addArgs({"-w", workingDir.path()});
     if (process.keepsWriteChannelOpen())
         cmd.addArg("-i");
+    if (env.size() != 0 && d->m_accessible != DockerDevicePrivate::Accessible) {
+        process.unsetEnvironment();
+        // FIXME the below would be probably correct if the respective tools would use correct
+        //       environment already, but most are using the host environment which usually makes
+        //       no sense on the device and may degrade performance
+        // const QStringList envList = env.toStringList();
+        // for (const QString &keyValue : envList) {
+        //     cmd.addArg("-e");
+        //     cmd.addArg(keyValue);
+        // }
+    }
     cmd.addArg(d->m_container);
     cmd.addArg(origCmd.executable().path()); // Cut off the docker://.../ bits.
     cmd.addArgs(origCmd.splitArguments(osType()));