[PATCH 3/3] git-pull.sh: introduce --[no-]autostash and pull.autostash

[Ramkumar Ramachandra <artagnon@gmail.com>]

This new configuration variable executes 'git stash' before attempting
to merge/rebase, and 'git stash pop' after a successful merge/rebase.
It makes it convenient for people to pull with dirty worktrees.

Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>
---
 Documentation/config.txt   |  5 ++++
 Documentation/git-pull.txt |  7 ++++++
 git-pull.sh                | 26 ++++++++++++++++++--
 t/t5521-pull-options.sh    | 59 ++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 95 insertions(+), 2 deletions(-)

diff --git a/Documentation/config.txt b/Documentation/config.txt
index c1f435f..0becafe 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -1786,6 +1786,11 @@ pull.rebase::
 	of merging the default branch from the default remote when "git
 	pull" is run. See "branch.<name>.rebase" for setting this on a
 	per-branch basis.
+
+pull.autostash::
+	When true, automatically stash all changes before attempting to
+	merge/rebase, and pop the stash after a successful
+	merge/rebase.
 +
 *NOTE*: this is a possibly dangerous operation; do *not* use
 it unless you understand the implications (see linkgit:git-rebase[1]
diff --git a/Documentation/git-pull.txt b/Documentation/git-pull.txt
index c975743..bb57c86 100644
--- a/Documentation/git-pull.txt
+++ b/Documentation/git-pull.txt
@@ -94,6 +94,13 @@ must be given before the options meant for 'git fetch'.
 	has to be called afterwards to bring the work tree up to date with the
 	merge result.
 
+--[no-]autostash::
+	When turned on, automatically stash all changes before
+	attempting to merge/rebase, and pop the stash after a
+	successful merge/rebase.  Useful for people who want to pull
+	with a dirty worktree.  This option can also be set via the
+	`pull.autostash` configuration variable.
+
 Options related to merging
 ~~~~~~~~~~~~~~~~~~~~~~~~~~
 
diff --git a/git-pull.sh b/git-pull.sh
index 37e1cd4..ad8e494 100755
--- a/git-pull.sh
+++ b/git-pull.sh
@@ -48,6 +48,7 @@ if test -z "$rebase"
 then
 	rebase=$(git config --bool pull.rebase)
 fi
+autostash=$(git config --bool pull.autostash)
 dry_run=
 while :
 do
@@ -116,6 +117,12 @@ do
 	--no-r|--no-re|--no-reb|--no-reba|--no-rebas|--no-rebase)
 		rebase=false
 		;;
+	--autostash)
+		autostash=true
+		;;
+	--no-autostash)
+		autostash=false
+		;;
 	--recurse-submodules)
 		recurse_submodules=--recurse-submodules
 		;;
@@ -196,7 +203,8 @@ test true = "$rebase" && {
 		then
 			die "$(gettext "updating an unborn branch with changes added to the index")"
 		fi
-	else
+	elif test "$autostash" = false
+	then
 		require_clean_work_tree "pull with rebase" "Please commit or stash them."
 	fi
 	oldremoteref= &&
@@ -213,6 +221,12 @@ test true = "$rebase" && {
 		fi
 	done
 }
+
+stash_required () {
+	! (git diff-files --quiet --ignore-submodules &&
+	git diff-index --quiet --cached HEAD --ignore-submodules)
+}
+
 orig_head=$(git rev-parse -q --verify HEAD)
 git fetch $verbosity $progress $dry_run $recurse_submodules --update-head-ok "$@" || exit 1
 test -z "$dry_run" || exit 0
@@ -288,4 +302,12 @@ true)
 	eval="$eval \"\$merge_name\" HEAD $merge_head"
 	;;
 esac
-eval "exec $eval"
+
+if test "$autostash" = true && stash_required
+then
+	git stash
+	eval "$eval"
+	test $? = 0 && git stash pop
+else
+	eval "exec $eval"
+fi
diff --git a/t/t5521-pull-options.sh b/t/t5521-pull-options.sh
index 4a804f0..cecacbc 100755
--- a/t/t5521-pull-options.sh
+++ b/t/t5521-pull-options.sh
@@ -90,4 +90,63 @@ test_expect_success 'git pull --all' '
 	)
 '
 
+test_expect_success 'pull --autostash with clean worktree' '
+	mkdir clonedautostash &&
+	(cd clonedautostash &&
+	git init &&
+	git pull --autostash ../parent &&
+	test_must_fail test_path_is_file .git/refs/stash
+	test_commit one
+	) &&
+	rm -rf clonedautostash
+'
+
+test_expect_success 'pull.autostash with clean worktree' '
+	mkdir clonedautostash &&
+	(cd clonedautostash &&
+	git init &&
+	test_config pull.autostash true &&
+	git pull ../parent &&
+	test_must_fail test_path_is_file .git/refs/stash
+	test_commit one
+	) &&
+	rm -rf clonedautostash
+'
+
+test_expect_success 'pull.autostash without conflict' '
+	mkdir clonedautostash &&
+	(cd clonedautostash &&
+	git init &&
+	test_commit "root_commit" &&
+	cat >quux <<-\EOF &&
+	this is a non-conflicting file
+	EOF
+	git add quux &&
+	test_config pull.autostash true &&
+	git pull ../parent &&
+	test_must_fail test_path_is_file .git/refs/stash &&
+	test_path_is_file quux &&
+	test_commit one
+	) &&
+	rm -rf clonedautostash
+'
+
+test_expect_success 'pull.autostash with conflict' '
+	mkdir clonedautostash &&
+	(cd clonedautostash &&
+	git init &&
+	test_commit "will_conflict" file "this is a conflicting file" &&
+	cat >quux <<-\EOF &&
+	this is a non-conflicting file
+	EOF
+	git add quux &&
+	test_config pull.autostash true &&
+	test_must_fail git pull ../parent &&
+	test_must_fail test_commit one &&
+	test_path_is_file .git/refs/stash &&
+	test_must_fail test_path_is_file quux
+	) &&
+	rm -rf clonedautostash
+'
+
 test_done
-- 
1.8.2.141.gad203c2.dirty