Adding experimental setting to clone with --shared flag

mdk/config-dist.json

@@ -301,6 +301,12 @@
     // by this setting.
     "useCacheAsUpstreamRemote": true,
 
+    // Clones the cached repository with the option --shared, which drastically reduces the
+    // size of the .git/ folder in each of the Moodle instances. Git reports this as a possible
+    // dangerous operation (https://git-scm.com/docs/git-clone) so it is not enabled by default.
+    // This requires the useCacheAsUpstreamRemote to be enabled.
+    "useCacheAsSharedClone": false,
+
     // You should not edit this, this is the branch that is considered as master by developers.
     "masterBranch": 400,
 

mdk/workplace.py

@@ -132,6 +132,9 @@ def create(self, name=None, version='master', integration=False, useCacheAsRemot
         extraLinkDir = os.path.join(self.getMdkWebDir(), name)
         branch = stableBranch(version)
 
+        useCacheAsUpstream = C.get('useCacheAsUpstreamRemote')
+        cloneAsShared = useCacheAsUpstream and C.get('useCacheAsSharedClone')
+
         if self.isMoodle(name):
             raise CreateException('The Moodle instance %s already exists' % name)
         elif os.path.isdir(installDir):
@@ -148,7 +151,8 @@ def create(self, name=None, version='master', integration=False, useCacheAsRemot
 
         # Clone the instances
         logging.info('Cloning repository...')
-        process(f'{C.get("git")} clone --branch {branch} --single-branch {repository} {wwwDir}')
+        process(f'{C.get("git")} clone --branch {branch} --single-branch '
+                f'{"--shared" if cloneAsShared else ""} {repository} {wwwDir}')
 
         # Symbolic link
         if os.path.islink(linkDir):
@@ -191,7 +195,7 @@ def create(self, name=None, version='master', integration=False, useCacheAsRemot
 
         # Fixing up remote URLs if need be, this is done after pulling the cache one because we
         # do not want to contact the real origin server from here, it is slow and pointless.
-        if not C.get('useCacheAsUpstreamRemote'):
+        if not useCacheAsUpstream:
             realupstream = C.get('remotes.integration') if integration else C.get('remotes.stable')
             if realupstream:
                 repo.setRemote(C.get('upstreamRemote'), realupstream)