From e03e4961c7a636fb5465b572a5f352f958e4f45c Mon Sep 17 00:00:00 2001
From: Carl Johnson <carljohnson@improbable.io>
Date: Mon, 12 Aug 2019 17:38:57 +0100
Subject: [PATCH] Allow client data to be re-used on a different host (#109)

---
 python/perforce.py      | 11 ++++++++++-
 python/test_perforce.py | 26 ++++++++++++++++++++++++++
 2 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/python/perforce.py b/python/perforce.py
index 8d9c236..5dce0d9 100644
--- a/python/perforce.py
+++ b/python/perforce.py
@@ -87,9 +87,18 @@ def _setup_client(self):
         self.perforce.save_client(client)
         self.perforce.client = clientname
 
-        if not os.path.isfile(os.path.join(self.root, "p4config")):
+        p4config = os.path.join(self.root, "p4config")
+        if not os.path.isfile(p4config):
             self.perforce.logger.warn("p4config missing, flushing workspace to revision zero")
             self.perforce.run_flush(['//...@0'])
+        else:
+            with open(p4config) as infile:
+                prev_clientname = next(line.split('=', 1)[-1]
+                    for line in infile.read().splitlines() # removes \n
+                    if line.startswith('P4CLIENT='))
+                if prev_clientname != clientname:
+                    self.perforce.logger.warn("p4config last client was %s, flushing workspace to match" % prev_clientname)
+                    self.perforce.run_flush(['//...@%s' % prev_clientname])
 
         self._write_p4config()
         self.created_client = True
diff --git a/python/test_perforce.py b/python/test_perforce.py
index 42a03fa..a976069 100644
--- a/python/test_perforce.py
+++ b/python/test_perforce.py
@@ -189,3 +189,29 @@ def test_backup_shelve():
         repo.unshelve(backup_changelist)
         with open(os.path.join(client_root, "file.txt")) as content:
             assert content.read() == "Goodbye World\n", "Unexpected content in workspace file"
+
+
+def copytree(src, dst):
+    """Shim to get around shutil.copytree requiring root dir to not exist"""
+    for item in os.listdir(src):
+        s = os.path.join(src, item)
+        d = os.path.join(dst, item)
+        if os.path.isdir(s):
+            shutil.copytree(s, d)
+        else:
+            shutil.copy2(s, d)
+
+def test_client_migration():
+    """Test re-use of workspace data when moved to another host"""
+    with setup_server_and_client() as client_root:
+        repo = P4Repo(root=client_root)
+
+        assert os.listdir(client_root) == [], "Workspace should be empty"
+        synced = repo.sync()
+        assert len(synced) > 0, "Didn't sync any files"
+
+        with tempfile.TemporaryDirectory(prefix="bk-p4-test-") as second_client_root:
+            copytree(client_root, second_client_root)
+            repo = P4Repo(root=second_client_root)
+            synced = repo.sync() # Flushes to match previous client, since p4config is there on disk
+            assert synced == [], "Should not have synced any files in second client"