rebase: add --show-current-patch

It is useful to see the full patch while resolving conflicts in a
rebase. The only way to do it now is

    less .git/rebase-*/patch

which could turn out to be a lot longer to type if you are in a
linked worktree, or not at top-dir. On top of that, an ordinary user
should not need to peek into .git directory. The new option is
provided to examine the patch.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-rebase.txt

@@ -12,7 +12,7 @@ SYNOPSIS
 	[<upstream> [<branch>]]
 'git rebase' [-i | --interactive] [options] [--exec <cmd>] [--onto <newbase>]
 	--root [<branch>]
-'git rebase' --continue | --skip | --abort | --quit | --edit-todo
+'git rebase' --continue | --skip | --abort | --quit | --edit-todo | --show-current-patch
 
 DESCRIPTION
 -----------
@@ -250,6 +250,10 @@ leave out at most one of A and B, in which case it defaults to HEAD.
 --edit-todo::
 	Edit the todo list during an interactive rebase.
 
+--show-current-patch::
+	Show the current patch in an interactive rebase or when rebase
+	is stopped because of conflicts.
+
 -m::
 --merge::
 	Use merging strategies to rebase.  When the recursive (default) merge

builtin/am.c

@@ -2126,6 +2126,17 @@ static int show_patch(struct am_state *state)
 	const char *patch_path;
 	int len;
 
+	if (!is_null_oid(&state->orig_commit)) {
+		const char *av[4] = { "show", NULL, "--", NULL };
+		char *new_oid_str;
+		int ret;
+
+		av[1] = new_oid_str = xstrdup(oid_to_hex(&state->orig_commit));
+		ret = run_command_v_opt(av, RUN_GIT_CMD);
+		free(new_oid_str);
+		return ret;
+	}
+
 	patch_path = am_path(state, msgnum(state));
 	len = strbuf_read_file(&sb, patch_path, 0);
 	if (len < 0)

contrib/completion/git-completion.bash

@@ -1992,11 +1992,11 @@ _git_rebase ()
 {
 	__git_find_repo_path
 	if [ -f "$__git_repo_path"/rebase-merge/interactive ]; then
-		__gitcomp "--continue --skip --abort --quit --edit-todo"
+		__gitcomp "--continue --skip --abort --quit --edit-todo --show-current-patch"
 		return
 	elif [ -d "$__git_repo_path"/rebase-apply ] || \
 	     [ -d "$__git_repo_path"/rebase-merge ]; then
-		__gitcomp "--continue --skip --abort --quit"
+		__gitcomp "--continue --skip --abort --quit --show-current-patch"
 		return
 	fi
 	__git_complete_strategy && return

git-rebase--am.sh

@@ -27,6 +27,9 @@ skip)
 	move_to_original_branch
 	return
 	;;
+show-current-patch)
+	exec git am --show-current-patch
+	;;
 esac
 
 if test -z "$rebase_root"

git-rebase--interactive.sh

@@ -840,6 +840,9 @@ To continue rebase after editing, run:
 
 	exit
 	;;
+show-current-patch)
+	exec git show "$(cat "$state_dir/stopped-sha")" --
+	;;
 esac
 
 comment_for_reflog start

git-rebase--merge.sh

@@ -137,6 +137,9 @@ skip)
 	finish_rb_merge
 	return
 	;;
+show-current-patch)
+	exec git show "$(cat "$state_dir/current")" --
+	;;
 esac
 
 mkdir -p "$state_dir"

git-rebase.sh

@@ -45,6 +45,7 @@ abort!             abort and check out the original branch
 skip!              skip current patch and continue
 edit-todo!         edit the todo list during an interactive rebase
 quit!              abort but keep HEAD where it is
+show-current-patch! show the patch file being applied or merged
 "
 . git-sh-setup
 set_reflog_action rebase
@@ -245,7 +246,7 @@ do
 	--verify)
 		ok_to_skip_pre_rebase=
 		;;
-	--continue|--skip|--abort|--quit|--edit-todo)
+	--continue|--skip|--abort|--quit|--edit-todo|--show-current-patch)
 		test $total_argc -eq 2 || usage
 		action=${1##--}
 		;;
@@ -412,6 +413,10 @@ quit)
 edit-todo)
 	run_specific_rebase
 	;;
+show-current-patch)
+	run_specific_rebase
+	die "BUG: run_specific_rebase is not supposed to return here"
+	;;
 esac
 
 # Make sure no rebase is in progress

t/t3400-rebase.sh

@@ -277,4 +277,37 @@ EOF
 	test_cmp From_.msg out
 '
 
+test_expect_success 'rebase--am.sh and --show-current-patch' '
+	test_create_repo conflict-apply &&
+	(
+		cd conflict-apply &&
+		test_commit init &&
+		echo one >>init.t &&
+		git commit -a -m one &&
+		echo two >>init.t &&
+		git commit -a -m two &&
+		git tag two &&
+		test_must_fail git rebase --onto init HEAD^ &&
+		GIT_TRACE=1 git rebase --show-current-patch >/dev/null 2>stderr &&
+		grep "show.*$(git rev-parse two)" stderr
+	)
+'
+
+test_expect_success 'rebase--merge.sh and --show-current-patch' '
+	test_create_repo conflict-merge &&
+	(
+		cd conflict-merge &&
+		test_commit init &&
+		echo one >>init.t &&
+		git commit -a -m one &&
+		echo two >>init.t &&
+		git commit -a -m two &&
+		git tag two &&
+		test_must_fail git rebase --merge --onto init HEAD^ &&
+		git rebase --show-current-patch >actual.patch &&
+		GIT_TRACE=1 git rebase --show-current-patch >/dev/null 2>stderr &&
+		grep "show.*$(git rev-parse two)" stderr
+	)
+'
+
 test_done

t/t3404-rebase-interactive.sh

@@ -225,6 +225,11 @@ test_expect_success 'stop on conflicting pick' '
 	test 0 = $(grep -c "^[^#]" < .git/rebase-merge/git-rebase-todo)
 '
 
+test_expect_success 'show conflicted patch' '
+	GIT_TRACE=1 git rebase --show-current-patch >/dev/null 2>stderr &&
+	grep "show.*$(cat "$state_dir/stopped-sha")" stderr
+'
+
 test_expect_success 'abort' '
 	git rebase --abort &&
 	test $(git rev-parse new-branch1) = $(git rev-parse HEAD) &&