snapshot: prohibit regular checkout on snapshot

Differential Revision: D17093630

fbshipit-source-id: 4425c90fbdecfa3edc9f34f677e0be6b771aa0af

edenscm/hgext/snapshot.py

@@ -14,6 +14,12 @@ for working with full snapshots of the working copy,
 including the untracked files and unresolved merge artifacts.
 
 TODO(alexeyqu): finish docs
+
+Configs::
+
+    [ui]
+    # Allow to run `hg checkout` for snapshot revisions
+    allow-checkout-snapshot = False
 """
 
 import hashlib
@@ -41,6 +47,10 @@ cmdtable = {}
 command = registrar.command(cmdtable)
 lfs = None
 
+configtable = {}
+configitem = registrar.configitem(configtable)
+configitem("ui", "allow-checkout-snapshot", default=False)
+
 
 def extsetup(ui):
     global lfs
@@ -49,6 +59,24 @@ def extsetup(ui):
     except KeyError:
         raise error.Abort(_("snapshot extension requires lfs to be enabled\n"))
 
+    extensions.wrapfunction(hg, "updaterepo", _updaterepo)
+
+
+def _updaterepo(orig, repo, node, overwrite, **opts):
+    allowsnapshots = repo.ui.configbool("ui", "allow-checkout-snapshot")
+    unfi = repo.unfiltered()
+    if not allowsnapshots and node in unfi:
+        ctx = unfi[node]
+        if "snapshotmetadataid" in ctx.extra():
+            raise error.Abort(
+                _(
+                    "%s is a snapshot, set ui.allow-checkout-snapshot"
+                    " config to True to checkout on it\n"
+                )
+                % ctx
+            )
+    return orig(repo, node, overwrite, **opts)
+
 
 @command("snapshot", [], "SUBCOMMAND ...", subonly=True)
 def snapshot(ui, repo, *args, **opts):

tests/test-fb-hgext-snapshot.t

@@ -263,6 +263,11 @@
   ? untrackedfile
 
 # Check out on the snapshot -- negative tests
+# Regular checkout
+  $ hg checkout --hidden "$OID"
+  abort: aaa7692160b6 is a snapshot, set ui.allow-checkout-snapshot config to True to checkout on it
+  
+  [255]
 # Non-empty WC state
   $ hg snapshot checkout "$OID"
   abort: You must have a clean working copy to checkout on a snapshot. Use --force to bypass that.