rebase: add -m/--message to rebase --collapse (issue2389) When collapsing changesets with rebase, you get a chance to edit the commit message manually, but there is no way to pass this message from the command line. This patch adds a `--message` (with short form `-m`) and `--logfile` (with short form `-m`) options to the rebase command. These options suppresses the generation of the default commit message, and instead use the message provided in the option (in case of `-m`) or in the file it points to (in case of `-l`). If you use this option without the `--collapse` option, it will raise an error. Options documentation edited by Patrick Mezard <pmezard@gmail.com>