git-p4: fully support unshelving changelists

The previous git-p4 unshelve support would check for changes
in Perforce to the files being unshelved since the original
shelve, and would complain if any were found.

This was to ensure that the user wouldn't end up with both the
shelved change delta, and some deltas from other changes in their
git commit.

e.g. given fileA:
      the
      quick
      brown
      fox

  change1: s/the/The/   <- p4 shelve this change
  change2: s/fox/Fox/   <- p4 submit this change
  git p4 unshelve 1     <- FAIL

This change teaches the P4Unshelve class to always create a parent
commit which matches the P4 tree (for the files being unshelved) at
the point prior to the P4 shelve being created (which is reported
in the p4 description for a shelved changelist).

That then means git-p4 can always create a git commit matching the
P4 shelve that was originally created, without any extra deltas.

The user might still need to use the --origin option though - there
is no way for git-p4 to work out the versions of all of the other
*unchanged* files in the shelve, since this information is not recorded
by Perforce.

Additionally this fixes handling of shelved 'move' operations.

Signed-off-by: Luke Diamand <luke@diamand.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 48 insertions, 36 deletions

diff --git a/git-p4.py b/git-p4.py
index 76c18a22e9..1998c3e141 100755
--- a/git-p4.py
+++ b/git-p4.py
@@ -1306,6 +1306,9 @@ class GitLFS(LargeFileSystem):
             return LargeFileSystem.processContent(self, git_mode, relPath, contents)
 
 class Command:
+    delete_actions = ( "delete", "move/delete", "purge" )
+    add_actions = ( "add", "move/add" )
+
     def __init__(self):
         self.usage = "usage: %prog [options]"
         self.needsGit = True
@@ -2524,7 +2527,6 @@ class View(object):
         return ""
 
 class P4Sync(Command, P4UserMap):
-    delete_actions = ( "delete", "move/delete", "purge" )
 
     def __init__(self):
         Command.__init__(self)
@@ -2612,20 +2614,7 @@ class P4Sync(Command, P4UserMap):
         if self.verbose:
             print("checkpoint finished: " + out)
 
-    def cmp_shelved(self, path, filerev, revision):
-        """ Determine if a path at revision #filerev is the same as the file
-            at revision @revision for a shelved changelist. If they don't match,
-            unshelving won't be safe (we will get other changes mixed in).
-
-            This is comparing the revision that the shelved changelist is *based* on, not
-            the shelved changelist itself.
-        """
-        ret = p4Cmd(["diff2", "{0}#{1}".format(path, filerev), "{0}@{1}".format(path, revision)])
-        if verbose:
-            print("p4 diff2 path %s filerev %s revision %s => %s" % (path, filerev, revision, ret))
-        return ret["status"] == "identical"
-
-    def extractFilesFromCommit(self, commit, shelved=False, shelved_cl = 0, origin_revision = 0):
+    def extractFilesFromCommit(self, commit, shelved=False, shelved_cl = 0):
         self.cloneExclude = [re.sub(r"\.\.\.$", "", path)
                              for path in self.cloneExclude]
         files = []
@@ -2650,17 +2639,6 @@ class P4Sync(Command, P4UserMap):
             file["type"] = commit["type%s" % fnum]
             if shelved:
                 file["shelved_cl"] = int(shelved_cl)
-
-                # For shelved changelists, check that the revision of each file that the
-                # shelve was based on matches the revision that we are using for the
-                # starting point for git-fast-import (self.initialParent). Otherwise
-                # the resulting diff will contain deltas from multiple commits.
-
-                if file["action"] != "add" and \
-                    not self.cmp_shelved(path, file["rev"], origin_revision):
-                    sys.exit("change {0} not based on {1} for {2}, cannot unshelve".format(
-                        commit["change"], self.initialParent, path))
-
             files.append(file)
             fnum = fnum + 1
         return files
@@ -3032,7 +3010,7 @@ class P4Sync(Command, P4UserMap):
             print('Ignoring file outside of prefix: {0}'.format(path))
         return hasPrefix
 
-    def commit(self, details, files, branch, parent = ""):
+    def commit(self, details, files, branch, parent = "", allow_empty=False):
         epoch = details["time"]
         author = details["user"]
         jobs = self.extractJobsFromCommit(details)
@@ -3046,7 +3024,10 @@ class P4Sync(Command, P4UserMap):
         files = [f for f in files
             if self.inClientSpec(f['path']) and self.hasBranchPrefix(f['path'])]
 
-        if not files and not gitConfigBool('git-p4.keepEmptyCommits'):
+        if gitConfigBool('git-p4.keepEmptyCommits'):
+            allow_empty = True
+
+        if not files and not allow_empty:
             print('Ignoring revision {0} as it would produce an empty commit.'
                 .format(details['change']))
             return
@@ -3387,10 +3368,10 @@ class P4Sync(Command, P4UserMap):
         else:
             return None
 
-    def importChanges(self, changes, shelved=False, origin_revision=0):
+    def importChanges(self, changes, origin_revision=0):
         cnt = 1
         for change in changes:
-            description = p4_describe(change, shelved)
+            description = p4_describe(change)
             self.updateOptionDict(description)
 
             if not self.silent:
@@ -3460,7 +3441,7 @@ class P4Sync(Command, P4UserMap):
                                 print("Parent of %s not found. Committing into head of %s" % (branch, parent))
                             self.commit(description, filesForCommit, branch, parent)
                 else:
-                    files = self.extractFilesFromCommit(description, shelved, change, origin_revision)
+                    files = self.extractFilesFromCommit(description)
                     self.commit(description, files, self.branch,
                                 self.initialParent)
                     # only needed once, to connect to the previous commit
@@ -3957,7 +3938,6 @@ class P4Unshelve(Command):
         self.verbose = False
         self.noCommit = False
         self.destbranch = "refs/remotes/p4-unshelved"
-        self.origin = "p4/master"
 
     def renameBranch(self, branch_name):
         """ Rename the existing branch to branch_name.N
@@ -3989,6 +3969,32 @@ class P4Unshelve(Command):
 
         sys.exit("could not find git-p4 commits in {0}".format(self.origin))
 
+    def createShelveParent(self, change, branch_name, sync, origin):
+        """ Create a commit matching the parent of the shelved changelist 'change'
+        """
+        parent_description = p4_describe(change, shelved=True)
+        parent_description['desc'] = 'parent for shelved changelist {}\n'.format(change)
+        files = sync.extractFilesFromCommit(parent_description, shelved=False, shelved_cl=change)
+
+        parent_files = []
+        for f in files:
+            # if it was added in the shelved changelist, it won't exist in the parent
+            if f['action'] in self.add_actions:
+                continue
+
+            # if it was deleted in the shelved changelist it must not be deleted
+            # in the parent - we might even need to create it if the origin branch
+            # does not have it
+            if f['action'] in self.delete_actions:
+                f['action'] = 'add'
+
+            parent_files.append(f)
+
+        sync.commit(parent_description, parent_files, branch_name,
+                parent=origin, allow_empty=True)
+        print("created parent commit for {0} based on {1} in {2}".format(
+            change, self.origin, branch_name))
+
     def run(self, args):
         if len(args) != 1:
             return False
@@ -3998,9 +4004,8 @@ class P4Unshelve(Command):
 
         sync = P4Sync()
         changes = args
-        sync.initialParent = self.origin
 
-        # use the first change in the list to construct the branch to unshelve into
+        # only one change at a time
         change = changes[0]
 
         # if the target branch already exists, rename it
@@ -4013,14 +4018,21 @@ class P4Unshelve(Command):
         sync.suppress_meta_comment = True
 
         settings = self.findLastP4Revision(self.origin)
-        origin_revision = settings['change']
         sync.depotPaths = settings['depot-paths']
         sync.branchPrefixes = sync.depotPaths
 
         sync.openStreams()
         sync.loadUserMapFromCache()
         sync.silent = True
-        sync.importChanges(changes, shelved=True, origin_revision=origin_revision)
+
+        # create a commit for the parent of the shelved changelist
+        self.createShelveParent(change, branch_name, sync, self.origin)
+
+        # create the commit for the shelved changelist itself
+        description = p4_describe(change, True)
+        files = sync.extractFilesFromCommit(description, True, change)
+
+        sync.commit(description, files, branch_name, "")
         sync.closeStreams()
 
         print("unshelved changelist {0} into {1}".format(change, branch_name))