v3git-p4: add option to preserve user names

contrib/fast-import/git-p4, contrib/fast-import/git-p4.txt, t/t9800-git-p4.sh

diff --git a/contrib/fast-import/git-p4 b/contrib/fast-import/git-p4
index 78e5b3a..6018507 100755
--- a/contrib/fast-import/git-p4
+++ b/contrib/fast-import/git-p4
@@ -474,6 +474,47 @@ class Command:
         self.usage = "usage: %prog [options]"
         self.needsGit = True
 
+class P4UserMap:
+    def __init__(self):
+        self.userMapFromPerforceServer = False
+
+    def getUserCacheFilename(self):
+        home = os.environ.get("HOME", os.environ.get("USERPROFILE"))
+        return home + "/.gitp4-usercache.txt"
+
+    def getUserMapFromPerforceServer(self):
+        if self.userMapFromPerforceServer:
+            return
+        self.users = {}
+        self.emails = {}
+
+        for output in p4CmdList("users"):
+            if not output.has_key("User"):
+                continue
+            self.users[output["User"]] = output["FullName"] + " <" + output["Email"] + ">"
+            self.emails[output["Email"]] = output["User"]
+
+
+        s = ''
+        for (key, val) in self.users.items():
+            s += "%s\t%s\n" % (key.expandtabs(1), val.expandtabs(1))
+
+        open(self.getUserCacheFilename(), "wb").write(s)
+        self.userMapFromPerforceServer = True
+
+    def loadUserMapFromCache(self):
+        self.users = {}
+        self.userMapFromPerforceServer = False
+        try:
+            cache = open(self.getUserCacheFilename(), "rb")
+            lines = cache.readlines()
+            cache.close()
+            for line in lines:
+                entry = line.strip().split("\t")
+                self.users[entry[0]] = entry[1]
+        except IOError:
+            self.getUserMapFromPerforceServer()
+
 class P4Debug(Command):
     def __init__(self):
         Command.__init__(self)
@@ -554,13 +595,16 @@ class P4RollBack(Command):
 
         return True
 
-class P4Submit(Command):
+class P4Submit(Command, P4UserMap):
     def __init__(self):
         Command.__init__(self)
+        P4UserMap.__init__(self)
         self.options = [
                 optparse.make_option("--verbose", dest="verbose", action="store_true"),
                 optparse.make_option("--origin", dest="origin"),
                 optparse.make_option("-M", dest="detectRenames", action="store_true"),
+                # preserve the user, requires relevant p4 permissions
+                optparse.make_option("--preserve-user", dest="preserveUser", action="store_true"),
         ]
         self.description = "Submit changes from git to the perforce depot."
         self.usage += " [name of git branch to submit into perforce depot]"
@@ -568,6 +612,7 @@ class P4Submit(Command):
         self.origin = ""
         self.detectRenames = False
         self.verbose = False
+        self.preserveUser = gitConfig("git-p4.preserveUser").lower() == "true"
         self.isWindows = (platform.system() == "Windows")
 
     def check(self):
@@ -602,6 +647,80 @@ class P4Submit(Command):
 
         return result
 
+    def p4UserForCommit(self,id):
+        # Return the tuple (perforce user,git email) for a given git commit id
+        self.getUserMapFromPerforceServer()
+        gitEmail = read_pipe("git log --max-count=1 --format='%%ae' %s" % id)
+        gitEmail = gitEmail.strip()
+        if not self.emails.has_key(gitEmail):
+            return (None,gitEmail)
+        else:
+            return (self.emails[gitEmail],gitEmail)
+
+    def checkValidP4Users(self,commits):
+        # check if any git authors cannot be mapped to p4 users
+        for id in commits:
+            (user,email) = self.p4UserForCommit(id)
+            if not user:
+                msg = "Cannot find p4 user for email %s in commit %s." % (email, id)
+                if gitConfig('git-p4.allowMissingP4Users').lower() == "true":
+                    print "%s" % msg
+                else:
+                    die("Error: %s\nSet git-p4.allowMissingP4Users to true to allow this." % msg)
+
+    def lastP4Changelist(self):
+        # Get back the last changelist number submitted in this client spec. This
+        # then gets used to patch up the username in the change. If the same
+        # client spec is being used by multiple processes then this might go
+        # wrong.
+        results = p4CmdList("client -o")        # find the current client
+        client = None
+        for r in results:
+            if r.has_key('Client'):
+                client = r['Client']
+                break
+        if not client:
+            die("could not get client spec")
+        results = p4CmdList("changes -c %s -m 1" % client)
+        for r in results:
+            if r.has_key('change'):
+                return r['change']
+        die("Could not get changelist number for last submit - cannot patch up user details")
+
+    def modifyChangelistUser(self, changelist, newUser):
+        # fixup the user field of a single changelist after it has been submitted.
+        changes = p4CmdList("change -o %s" % changelist)
+        input = ''
+        for c in changes:
+            if c.has_key('User'):
+                if c['User'] == newUser:
+                    # nothing to do here
+                    return
+                c['User'] = newUser
+
+            input = input + marshal.dumps(c)
+
+        result = p4CmdList("change -f -i", stdin=input)
+        for r in result:
+            if r.has_key('code'):
+                if r['code'] == 'error':
+                    die("Could not modify user field of changelist %s to %s:%s" % (changelist, newUser, r['data']))
+            if r.has_key('data'):
+                print("Updated user field for changelist %s to %s" % (changelist, newUser))
+                return
+        die("Could not modify user field of changelist %s to %s" % (changelist, newUser))
+    def canChangeChangelists(self):
+        # check to see if we have p4 admin or super-user permissions, either of
+        # which are required to modify changelists.
+        results = p4CmdList("protects %s" % self.depotPath)
+        for r in results:
+            if r.has_key('perm'):
+                if r['perm'] == 'admin':
+                    return 1
+                if r['perm'] == 'super':
+                    return 1
+        return 0
+
     def prepareSubmitTemplate(self):
         # remove lines in the Files section that show changes to files outside the depot path we're committing into
         template = ""
@@ -631,6 +750,9 @@ class P4Submit(Command):
     def applyCommit(self, id):
         print "Applying %s" % (read_pipe("git log --max-count=1 --pretty=oneline %s" % id))
 
+        if self.preserveUser:
+            (p4User, gitEmail) = self.p4UserForCommit(id)
+
         if not self.detectRenames:
             # If not explicitly set check the config variable
             self.detectRenames = gitConfig("git-p4.detectRenames").lower() == "true"
@@ -748,6 +870,10 @@ class P4Submit(Command):
 
         if self.interactive:
             submitTemplate = self.prepareLogMessage(template, logMessage)
+
+            if self.preserveUser:
+               submitTemplate = submitTemplate + ("\n######## Actual user %s, modified after commit\n" % p4User)
+
             if os.environ.has_key("P4DIFF"):
                 del(os.environ["P4DIFF"])
             diff = ""
@@ -781,8 +907,13 @@ class P4Submit(Command):
                 editor = read_pipe("git var GIT_EDITOR").strip()
             system(editor + " " + fileName)
 
+            if gitConfig("git-p4.skipSubmitEditCheck") == "true":
+                checkModTime = False
+            else:
+                checkModTime = True
+
             response = "y"
-            if os.stat(fileName).st_mtime <= mtime:
+            if checkModTime and (os.stat(fileName).st_mtime <= mtime):
                 response = "x"
                 while response != "y" and response != "n":
                     response = raw_input("Submit template unchanged. Submit anyway? [y]es, [n]o (skip this patch) ")
@@ -795,6 +926,14 @@ class P4Submit(Command):
                 if self.isWindows:
                     submitTemplate = submitTemplate.replace("\r\n", "\n")
                 p4_write_pipe("submit -i", submitTemplate)
+
+                if self.preserveUser:
+                    if p4User:
+                        # Get last changelist number. Cannot easily get it from
+                        # the submit command output as the output is unmarshalled.
+                        changelist = self.lastP4Changelist()
+                        self.modifyChangelistUser(changelist, p4User)
+
             else:
                 for f in editedFiles:
                     p4_system("revert \"%s\"" % f);
@@ -831,6 +970,10 @@ class P4Submit(Command):
         if len(self.origin) == 0:
             self.origin = upstream
 
+        if self.preserveUser:
+            if not self.canChangeChangelists():
+                die("Cannot preserve user names without p4 super-user or admin permissions")
+
         if self.verbose:
             print "Origin branch is " + self.origin
 
@@ -858,6 +1001,9 @@ class P4Submit(Command):
             commits.append(line.strip())
         commits.reverse()
 
+        if self.preserveUser:
+            self.checkValidP4Users(commits)
+
         while len(commits) > 0:
             commit = commits[0]
             commits = commits[1:]
@@ -877,11 +1023,12 @@ class P4Submit(Command):
 
         return True
 
-class P4Sync(Command):
+class P4Sync(Command, P4UserMap):
     delete_actions = ( "delete", "move/delete", "purge" )
 
     def __init__(self):
         Command.__init__(self)
+        P4UserMap.__init__(self)
         self.options = [
                 optparse.make_option("--branch", dest="branch"),
                 optparse.make_option("--detect-branches", dest="detectBranches", action="store_true"),
@@ -1236,41 +1383,6 @@ class P4Sync(Command):
                     print ("Tag %s does not match with change %s: file count is different."
                            % (labelDetails["label"], change))
 
-    def getUserCacheFilename(self):
-        home = os.environ.get("HOME", os.environ.get("USERPROFILE"))
-        return home + "/.gitp4-usercache.txt"
-
-    def getUserMapFromPerforceServer(self):
-        if self.userMapFromPerforceServer:
-            return
-        self.users = {}
-
-        for output in p4CmdList("users"):
-            if not output.has_key("User"):
-                continue
-            self.users[output["User"]] = output["FullName"] + " <" + output["Email"] + ">"
-
-
-        s = ''
-        for (key, val) in self.users.items():
-            s += "%s\t%s\n" % (key.expandtabs(1), val.expandtabs(1))
-
-        open(self.getUserCacheFilename(), "wb").write(s)
-        self.userMapFromPerforceServer = True
-
-    def loadUserMapFromCache(self):
-        self.users = {}
-        self.userMapFromPerforceServer = False
-        try:
-            cache = open(self.getUserCacheFilename(), "rb")
-            lines = cache.readlines()
-            cache.close()
-            for line in lines:
-                entry = line.strip().split("\t")
-                self.users[entry[0]] = entry[1]
-        except IOError:
-            self.getUserMapFromPerforceServer()
-
     def getLabels(self):
         self.labels = {}
 
diff --git a/contrib/fast-import/git-p4.txt b/contrib/fast-import/git-p4.txt
index e09da44..b6986f0 100644
--- a/contrib/fast-import/git-p4.txt
+++ b/contrib/fast-import/git-p4.txt
@@ -110,6 +110,12 @@ is not your current git branch you can also pass that as an argument:
 
 You can override the reference branch with the --origin=mysourcebranch option.
 
+The Perforce changelists will be created with the user who ran git-p4. If you
+use --preserve-user then git-p4 will attempt to create Perforce changelists
+with the Perforce user corresponding to the git commit author. You need to
+have sufficient permissions within Perforce, and the git users need to have
+Perforce accounts. Permissions can be granted using 'p4 protect'.
+
 If a submit fails you may have to "p4 resolve" and submit manually. You can
 continue importing the remaining changes with
 
@@ -196,6 +202,29 @@ able to find the relevant client.  This client spec will be used to
 both filter the files cloned by git and set the directory layout as
 specified in the client (this implies --keep-path style semantics).
 
+git-p4.skipSubmitModTimeCheck
+
+  git config [--global] git-p4.skipSubmitModTimeCheck false
+
+If true, submit will not check if the p4 change template has been modified.
+
+git-p4.preserveUser
+
+  git config [--global] git-p4.preserveUser false
+
+If true, attempt to preserve user names by modifying the p4 changelists. See
+the "--preserve-user" submit option.
+
+git-p4.allowMissingPerforceUsers
+
+  git config [--global] git-p4.allowMissingP4Users false
+
+If git-p4 is setting the perforce user for a commit (--preserve-user) then
+if there is no perforce user corresponding to the git author, git-p4 will
+stop. With allowMissingPerforceUsers set to true, git-p4 will use the
+current user (i.e. the behavior without --preserve-user) and carry on with
+the perforce commit.
+
 Implementation Details...
 =========================
 
diff --git a/t/t9800-git-p4.sh b/t/t9800-git-p4.sh
index a523473..fd3204b 100755
--- a/t/t9800-git-p4.sh
+++ b/t/t9800-git-p4.sh
@@ -12,6 +12,8 @@ test_description='git-p4 tests'
 GITP4=$GIT_BUILD_DIR/contrib/fast-import/git-p4
 P4DPORT=10669
 
+export P4PORT=localhost:$P4DPORT
+
 db="$TRASH_DIRECTORY/db"
 cli="$TRASH_DIRECTORY/cli"
 git="$TRASH_DIRECTORY/git"
@@ -129,6 +131,88 @@ test_expect_success 'clone bare' '
 	rm -rf "$git" && mkdir "$git"
 '
 
+p4_add_user() {
+    name=$1
+    fullname=$2
+    p4 user -f -i <<EOF &&
+User: $name
+Email: $name@localhost
+FullName: $fullname
+EOF
+    p4 passwd -P secret $name
+}
+
+p4_grant_admin() {
+    name=$1
+    p4 protect -o |\
+        awk "{print}END{print \"    admin user $name * //depot/...\"}" |\
+        p4 protect -i
+}
+
+p4_check_commit_author() {
+    file=$1
+    user=$2
+    if p4 changes -m 1 //depot/$file | grep $user > /dev/null ; then
+        return 0
+    else
+        echo "file $file not modified by user $user" 1>&2
+        return 1
+    fi
+}
+
+# Test username support, submitting as user 'alice'
+test_expect_success 'preserve users' '
+	p4_add_user alice Alice &&
+	p4_add_user bob Bob &&
+	p4_grant_admin alice &&
+	"$GITP4" clone --dest="$git" //depot &&
+	cd "$git" &&
+	echo "username: a change by alice" >> file1 &&
+	echo "username: a change by bob" >> file2 &&
+	git commit --author "Alice <alice@localhost>" -m "a change by alice" file1 &&
+	git commit --author "Bob <bob@localhost>" -m "a change by bob" file2 &&
+	git config git-p4.skipSubmitEditCheck true &&
+	P4EDITOR=touch P4USER=alice P4PASSWD=secret "$GITP4" commit --preserve-user &&
+	p4_check_commit_author file1 alice &&
+	p4_check_commit_author file2 bob &&
+	cd "$TRASH_DIRECTORY" &&
+	rm -rf "$git" && mkdir "$git"
+'
+
+# Test username support, submitting as bob, who lacks admin rights. Should
+# not submit change to p4 (git diff should show deltas).
+test_expect_success 'refuse to preserve users without perms' '
+	"$GITP4" clone --dest="$git" //depot &&
+	cd "$git" &&
+	echo "username-noperms: a change by alice" >> file1 &&
+	git commit --author "Alice <alice@localhost>" -m "perms: a change by alice" file1 &&
+	! P4EDITOR=touch P4USER=bob P4PASSWD=secret "$GITP4" commit --preserve-user &&
+	! git diff --exit-code HEAD..p4/master > /dev/null &&
+	cd "$TRASH_DIRECTORY" &&
+	rm -rf "$git" && mkdir "$git"
+'
+
+# What happens with unknown author? Without allowMissingP4Users it should fail.
+test_expect_success 'preserve user where author is unknown to p4' '
+	"$GITP4" clone --dest="$git" //depot &&
+	cd "$git" &&
+	git config git-p4.skipSubmitEditCheck true
+	echo "username-bob: a change by bob" >> file1 &&
+	git commit --author "Bob <bob@localhost>" -m "preserve: a change by bob" file1 &&
+	echo "username-unknown: a change by charlie" >> file1 &&
+	git commit --author "Charlie <charlie@localhost>" -m "preserve: a change by charlie" file1 &&
+	! P4EDITOR=touch P4USER=alice P4PASSWD=secret "$GITP4" commit --preserve-user &&
+	! git diff --exit-code HEAD..p4/master > /dev/null &&
+	echo "$0: repeat with allowMissingP4Users enabled" &&
+	git config git-p4.allowMissingP4Users true &&
+	git config git-p4.preserveUser true &&
+	P4EDITOR=touch P4USER=alice P4PASSWD=secret "$GITP4" commit &&
+	git diff --exit-code HEAD..p4/master > /dev/null &&
+	p4_check_commit_author file1 alice &&
+	cd "$TRASH_DIRECTORY" &&
+	rm -rf "$git" && mkdir "$git"
+'
+
 test_expect_success 'shutdown' '
 	pid=`pgrep -f p4d` &&
 	test -n "$pid" &&

diff --git a/contrib/fast-import/git-p4 b/contrib/fast-import/git-p4
index 36e3d87..6018507 100755
--- a/contrib/fast-import/git-p4
+++ b/contrib/fast-import/git-p4
@@ -688,12 +688,18 @@ class P4Submit(Command, P4UserMap):
         die("Could not get changelist number for last submit - cannot patch up user details")
 
     def modifyChangelistUser(self, changelist, newUser):
-        # fixup the user field of a changelist after it has been submitted.
+        # fixup the user field of a single changelist after it has been submitted.
         changes = p4CmdList("change -o %s" % changelist)
+        input = ''
         for c in changes:
             if c.has_key('User'):
+                if c['User'] == newUser:
+                    # nothing to do here
+                    return
                 c['User'] = newUser
-        input = marshal.dumps(changes[0])
+
+            input = input + marshal.dumps(c)
+
         result = p4CmdList("change -f -i", stdin=input)
         for r in result:
             if r.has_key('code'):
@@ -703,11 +709,10 @@ class P4Submit(Command, P4UserMap):
                 print("Updated user field for changelist %s to %s" % (changelist, newUser))
                 return
         die("Could not modify user field of changelist %s to %s" % (changelist, newUser))
-
     def canChangeChangelists(self):
         # check to see if we have p4 admin or super-user permissions, either of
         # which are required to modify changelists.
-        results = p4CmdList("-G protects %s" % self.depotPath)
+        results = p4CmdList("protects %s" % self.depotPath)
         for r in results:
             if r.has_key('perm'):
                 if r['perm'] == 'admin':
@@ -865,6 +870,10 @@ class P4Submit(Command, P4UserMap):
 
         if self.interactive:
             submitTemplate = self.prepareLogMessage(template, logMessage)
+
+            if self.preserveUser:
+               submitTemplate = submitTemplate + ("\n######## Actual user %s, modified after commit\n" % p4User)
+
             if os.environ.has_key("P4DIFF"):
                 del(os.environ["P4DIFF"])
             diff = ""