eagerpeer: add clone support

Summary:
Add clone endpoint so we can clone from an eager test repo.

Note: the master group is empty and "cloneata" does not quite work yet due to
EagerRepo not writing to the master group. It will be fixed later.

Reviewed By: DurhamG

Differential Revision: D27971121

fbshipit-source-id: 0cc35136c6987673c2c4fbbd892c344c3586fcb7

eden/scm/edenscm/mercurial/clone.py

@@ -117,3 +117,28 @@ def emergencyclone(source, repo):
 
             repo.invalidate()
             repo.invalidatechangelog()
+
+
+def segmentsclone(source, clonedata, repo):
+    """clone using segmented changelog's CloneData
+
+    This produces a repo with lazy commit hashes.
+    """
+    with repo.wlock(), repo.lock(), repo.transaction("clone"):
+        changelog2.migrateto(repo, "lazy")
+        repo.requirements.add("remotefilelog")
+        repo._writerequirements()
+
+        repo.ui.status(_("populating main commit graph\n"))
+        repo.changelog.inner.importclonedata(clonedata)
+        tip = repo.changelog.dag.all().first()
+        if tip:
+            repo.ui.status(_("tip commit: %s\n") % hex(tip))
+            repo.svfs.write("tip", tip)
+
+        repo.ui.status(_("fetching selected remote bookmarks\n"))
+        remote = bookmod.remotenameforurl(repo.ui, repo.ui.paths.getpath(source).rawloc)
+        assert remote is not None
+        repo.pull(
+            source, bookmarknames=bookmod.selectivepullbookmarknames(repo, remote)
+        )

eden/scm/edenscm/mercurial/eagerpeer.py

@@ -98,6 +98,11 @@ class eagerpeer(repository.peer):
                 )
             yield node, parents
 
+    # Clone using dag::CloneData (designed for lazy backend)
+
+    def clonedata(self):
+        return self.edenapi.clonedata(self._reponame)
+
     # The Python "peer" interface.
     # Prefer using EdenAPI to implement them.
 
@@ -132,6 +137,7 @@ class eagerpeer(repository.peer):
             "branchmap",
             "addblobs",
             "commitgraph",
+            "clonedata",
         }
 
     def debugwireargs(self, one, two, three=None, four=None, five=None):

eden/scm/edenscm/mercurial/hg.py

@@ -592,9 +592,14 @@ def clone(
                     )
                 revs = [srcpeer.lookup(r) for r in rev]
                 checkout = revs[0]
+
+            # Can we use EdenAPI CloneData?
+            if srcpeer.capable("clonedata") and shallow and not update:
+                data = srcpeer.clonedata()
+                clonemod.segmentsclone(srcpeer.url(), data, destrepo)
             # Can we use the new code path (stream clone + shallow + no
             # update + selective pull)?
-            if (
+            elif (
                 destrepo
                 and not pull
                 and not update

eden/scm/tests/test-eager-exchange.t

@@ -118,3 +118,22 @@ Trigger file and tree downloading:
    TRACE eagerepo::api:  found: 35e7525ce3a48913275d7061dd9a867ffef1e34d, 41 bytes
   AB (no-eol)
 
+Clone:
+
+  $ cd $TESTTMP
+  $ hg clone -U --shallow eager:$TESTTMP/e1 cloned
+   DEBUG eagerepo::api: clone_data
+  populating main commit graph
+  fetching selected remote bookmarks
+   DEBUG eagerepo::api: bookmarks master
+   DEBUG edenscm::mercurial::eagerpeer: listkeyspatterns(bookmarks, ['master']) = sortdict([('master', 'dc0947a82db884575bb76ea10ac97b08536bfa03')])
+   DEBUG eagerepo::api: bookmarks master
+   DEBUG edenscm::mercurial::eagerpeer: listkeyspatterns(bookmarks, ['master']) = sortdict([('master', 'dc0947a82db884575bb76ea10ac97b08536bfa03')])
+   DEBUG eagerepo::api: bookmarks master
+   DEBUG edenscm::mercurial::eagerpeer: listkeyspatterns(bookmarks, ['master']) = sortdict([('master', 'dc0947a82db884575bb76ea10ac97b08536bfa03')])
+   DEBUG eagerepo::api: commit_known 
+   DEBUG eagerepo::api: commit_graph dc0947a82db884575bb76ea10ac97b08536bfa03 
+   TRACE edenscm::mercurial::eagerpeer: graph node 426bada5c67598ca65036d57d9e4b64b0c1ce7a0 []
+   TRACE edenscm::mercurial::eagerpeer: graph node dc0947a82db884575bb76ea10ac97b08536bfa03 ['426bada5c67598ca65036d57d9e4b64b0c1ce7a0']
+   DEBUG eagerepo::api: bookmarks master
+   DEBUG edenscm::mercurial::eagerpeer: listkeyspatterns(bookmarks, ['master']) = sortdict([('master', 'dc0947a82db884575bb76ea10ac97b08536bfa03')])