localrepo: set files to empty for subtree shallow copy commits

Summary: For subtree shallow copy commit, we don't traverse the tree to find all the files. So the "files" list in the commit text will be empty for pure subtree shallow copy. Further more, we want to make the "files" list empty for any commits that contains subtree shallow copy, since the "files" list will not have all the changed files if the commit contains a shallow copy.

Reviewed By: muirdm

Differential Revision: D66193902

fbshipit-source-id: 3aaf5a95533112060fd52d6c69b2e2ba0c0efe7d

eden/scm/sapling/localrepo.py

@@ -75,6 +75,7 @@
 from .i18n import _, _n
 from .node import bin, hex, nullhex, nullid
 from .pycompat import range
+from .utils import subtreeutil
 
 release = lockmod.release
 urlerr = util.urlerr
@@ -2825,6 +2826,12 @@ def commitctx(self, ctx, error=False):
             extra = ctx.extra().copy()
             if isgit:
                 git.update_extra_with_git_committer(self.ui, ctx, extra)
+
+            if subtreeutil.extra_contains_shallow_copy(extra):
+                # the file list can be large for a shallow copy, so don't
+                # put it in the files of commit text
+                files = []
+
             n = self.changelog.add(
                 mn,
                 files,

eden/scm/sapling/utils/subtreeutil.py

@@ -406,6 +406,20 @@ def contains_shallow_copy(repo, node):
     return False
 
 
+def extra_contains_shallow_copy(extra) -> bool:
+    """Check if the given commitctx extra contains any shallow copy metadata.
+
+    N.B. This function does not apply to "v0" subtree metadata because "v0" does
+    not have shallow copy type. It is used for newly incoming commits.
+    """
+    shallow_copy_key = BranchType.SHALLOW_COPY.to_key()
+    if metadata_list := _get_subtree_metadata(extra, SUBTREE_KEY):
+        for metadata in metadata_list:
+            if shallow_copy_key in metadata:
+                return True
+    return False
+
+
 def check_commit_splitability(repo, node):
     """Check if the given commit can be split into multiple commits.
 

eden/scm/tests/test-subtree-shallow-copy.t

@@ -0,0 +1,29 @@
+  $ setconfig diff.git=True
+  $ setconfig subtree.copy-reuse-tree=True
+  $ setconfig subtree.allow-any-source-commit=True
+
+test subtree copy
+  $ newclientrepo
+  $ drawdag <<'EOS'
+  > B   # B/foo/x = bbb\n
+  > |
+  > A   # A/foo/x = aaa\n
+  >     # drawdag.defaultfiles=false
+  > EOS
+  $ hg go $B -q
+  $ hg subtree cp -r $A --from-path foo --to-path bar -m "subtree copy foo -> bar"
+  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  $ hg dbsh -c 'print(repo["."].extra())'
+  {'branch': 'default', 'test_subtree': '[{"copies":[{"from_commit":"d908813f0f7c9078810e26aad1e37bdb32013d4b","from_path":"foo","to_path":"bar"}],"v":1}]'}
+  $ hg dbsh -c 'print(repo["."].changeset().files)'
+  ()
+
+files list is still empty after amending the shallow copy commit
+  $ echo ccc >> bar/x
+  $ hg amend
+  $ hg dbsh -c 'print(repo["."].extra())'
+  {'branch': 'default', 'amend_source': '075709eca377ab1f8a1e6a31b7970d26ff9ec935', 'test_subtree': '[{"copies":[{"from_commit":"d908813f0f7c9078810e26aad1e37bdb32013d4b","from_path":"foo","to_path":"bar"}],"v":1}]'}
+  $ hg dbsh -c 'print(repo["."].changeset().files)'
+  ()
+  $ hg dbsh -c 'print(repo["."].files())'
+  ['bar/x']