multiple -m

sync, assist, import: Allow -m option to be specified multiple times, to
provide additional paragraphs for the commit message.

The option parser didn't allow multiple -m before, so there is no risk of
behavior change breaking something that was for some reason using multiple
-m already.

Pass through to git commands, so that the method used to assemble the
paragrahs is whatever git does. Which might conceivably change in the
future.

Note that git commit-tree has supported -m since git 1.7.7. commitTree
was probably not using it since it predates that version. Since the
configure script prevents building git-annex with git older than 2.1,
there is no risk that it's not supported now.

Sponsored-by: Nicholas Golder-Manning on Patreon

Annex/AdjustedBranch.hs

@@ -469,7 +469,7 @@ commitAdjustedTree' treesha (BasisBranch basis) parents =
 			(commitCommitterMetaData basiscommit)
 			(mkcommit cmode)
 	mkcommit cmode = Git.Branch.commitTree cmode
-		adjustedBranchCommitMessage parents treesha
+		[adjustedBranchCommitMessage] parents treesha
 
 {- This message should never be changed. -}
 adjustedBranchCommitMessage :: String
@@ -577,7 +577,7 @@ reverseAdjustedCommit commitparent adj (csha, basiscommit) origbranch
 			(commitAuthorMetaData basiscommit)
 			(commitCommitterMetaData basiscommit) $
 				Git.Branch.commitTree cmode
-					(commitMessage basiscommit)
+					[commitMessage basiscommit]
 					[commitparent] treesha
 		return (Right revadjcommit)