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
git config [--global] git-p4.useclientspec false
+The P4CLIENT environment variable should be correctly set for p4 to be
+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.
+
+git-p4.skipUserNameCheck
+
+ git config [--global] git-p4.skipUserNameCheck false
+
+When submitting, git-p4 checks that the git commits are authored by the current
+p4 user, and warns if they are not. This disables the check.
+
Implementation Details...
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