subtree: expose the 'subtree.copy-max-file-count' config to users

Summary: Expose the 'subtree.copy-max-file-count' config to users, so users can override if needed.

Reviewed By: quark-zju

Differential Revision: D68643111

fbshipit-source-id: b162ce8d6885b53acc15d20f255c5074f23e5c71

eden/scm/sapling/commands/subtree.py

@@ -434,8 +434,22 @@ def prefetch(repo, path, fileids):
         file_count += len(fileids)
         if file_count > limit:
             support = ui.config("ui", "supportcontact")
-            hint = _("contact %s for help") % support if support else ""
-            raise error.Abort(_("subtree copy includes too many files"), hint=hint)
+            help_hint = _("contact %s for help") % support if support else None
+            override_hint = _(
+                "use '--config subtree.copy-max-file-count=N' cautiously to override"
+            )
+            hint = (
+                _("%s or %s") % (help_hint, override_hint)
+                if help_hint
+                else override_hint
+            )
+            raise error.Abort(
+                _(
+                    "subtree copy includes too many files (%d), exceeding configured limit (%d)"
+                )
+                % (file_count, limit),
+                hint=hint,
+            )
         path_to_fileids[path] = fileids
 
     new_files = []

eden/scm/tests/test-subtree.t

@@ -146,11 +146,12 @@ abort when subtree copy too many files
   >     # drawdag.defaultfiles=false
   > EOS  
   $ hg subtree cp -r $A --from-path foo --to-path bar --config subtree.copy-max-file-count=1
-  abort: subtree copy includes too many files
+  abort: subtree copy includes too many files (2), exceeding configured limit (1)
+  (use '--config subtree.copy-max-file-count=N' cautiously to override)
   [255]
   $ hg subtree cp -r $A --from-path foo --to-path bar --config subtree.copy-max-file-count=1 --config ui.supportcontact="Sapling Team"
-  abort: subtree copy includes too many files
-  (contact Sapling Team for help)
+  abort: subtree copy includes too many files (2), exceeding configured limit (1)
+  (contact Sapling Team for help or use '--config subtree.copy-max-file-count=N' cautiously to override)
   [255]