From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <git-owner@vger.kernel.org>
X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on dcvr.yhbt.net
X-Spam-Level: 
X-Spam-Status: No, score=-3.7 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED,
	DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM,
	HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_PASS,
	SPF_PASS shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2
Received: from vger.kernel.org (vger.kernel.org [23.128.96.18])
	by dcvr.yhbt.net (Postfix) with ESMTP id 455171F5AE
	for <e@yhbt.net>; Sat, 13 Jun 2020 14:25:33 +0000 (UTC)
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1726280AbgFMOZ3 (ORCPT <rfc822;e@yhbt.net>);
        Sat, 13 Jun 2020 10:25:29 -0400
Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49140 "EHLO
        lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S1726102AbgFMOZ2 (ORCPT <rfc822;git@vger.kernel.org>);
        Sat, 13 Jun 2020 10:25:28 -0400
Received: from mail-qk1-x743.google.com (mail-qk1-x743.google.com [IPv6:2607:f8b0:4864:20::743])
        by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 030F7C03E96F
        for <git@vger.kernel.org>; Sat, 13 Jun 2020 07:25:27 -0700 (PDT)
Received: by mail-qk1-x743.google.com with SMTP id q8so11712662qkm.12
        for <git@vger.kernel.org>; Sat, 13 Jun 2020 07:25:27 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
        d=gmail.com; s=20161025;
        h=from:to:subject:date:message-id:mime-version
         :content-transfer-encoding;
        bh=DghuTSbX4zxMdv4AE3Dx+fuWr8PHfn3QrPhRR6s/d90=;
        b=MjMahsNOYe7zBv9b+B9wv5ai/L7G04tOjuqnjuDR9VyQBPmP026INHWb2Nb6ui1xSh
         VC4iXiJT6F76Ma3IGs4QnO4tfx9bK+5SiTkiY/wPFsk01yL0XL4MIfuCMAsaLmNgTnJg
         V09ZbY9b/hlCJD7PieVYFTvwkSELuS8rneBjWmqtXVdqDy/yxnTM7G+DvG70hTT/b8/y
         G44tfkgFX+gOqDgJALMDGBDTw3msKe3FeuUrqtxrRKrIRTxcye+/tgasLdCw43HFyFcT
         f3gqmpwKfdYerFpaIB2ZBDYWEigUnSWM8dXydaskDdVWkTewnbhdyHtpThZmHkte4M93
         lpYg==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
        d=1e100.net; s=20161025;
        h=x-gm-message-state:from:to:subject:date:message-id:mime-version
         :content-transfer-encoding;
        bh=DghuTSbX4zxMdv4AE3Dx+fuWr8PHfn3QrPhRR6s/d90=;
        b=K9ElpxE+hhSimYO8/N7jYyS0YDM1IYH9CnR4TWCXho8SswiozJyOnjGEUfCH+++Yqf
         znbpY41osaEwsZMlnpNQ4XcBYaE/VckhiefVf7UT3ZmmX5ndyrykZWNWNxb1q9zcfnoG
         JG/BO+YVaSOL0MXDsFiAQIXqtJ5YFqsvrgGqbgDmYqlvTGLgEBYUlNmHVmOpQdBA7w60
         kqYngYLrqDrJaKgRuCdel2y6k5WdDhfk5HiMVsqSUjBZj5Oyl6u/U8QiuhztDG3T6rLc
         DXsdnsvrQ3Sq0BwcOROESdM5qJH/mf7liq9L9Hb2tcN80lkyQGOmEAvl3py+tCQ6w5R8
         3ggA==
X-Gm-Message-State: AOAM5317Kd2AFZkSst3Xi+T3SO6AL2Ss3toywwsfoBuXbzOCnD1+QXBP
        IDanYxPMb/EBi/mDBmjBOp1uy2QKAWU=
X-Google-Smtp-Source: ABdhPJzTfktEqtWlPPpbv9lZJ8wmKYZ4nU7ijdTUET3CN3N0W1EgmWMdnP5R5zG/FgaqzVfgyhNrQQ==
X-Received: by 2002:a37:a648:: with SMTP id p69mr7842561qke.190.1592058326747;
        Sat, 13 Jun 2020 07:25:26 -0700 (PDT)
Received: from archbookpro.localdomain (CPE18593399858a-CM185933998587.cpe.net.cable.rogers.com. [174.112.65.113])
        by smtp.gmail.com with ESMTPSA id x36sm7144232qtd.97.2020.06.13.07.25.25
        for <git@vger.kernel.org>
        (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256);
        Sat, 13 Jun 2020 07:25:26 -0700 (PDT)
From:   Denton Liu <liu.denton@gmail.com>
To:     Git Mailing List <git@vger.kernel.org>
Subject: [PATCH] checkout: teach --worktree
Date:   Sat, 13 Jun 2020 10:25:12 -0400
Message-Id: <d10cb03dd8ce00cb6033c61ff9b9b30bbf5f9c89.1592058281.git.liu.denton@gmail.com>
X-Mailer: git-send-email 2.27.0.132.g321788e831
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Sender: git-owner@vger.kernel.org
Precedence: bulk
List-ID: <git.vger.kernel.org>
X-Mailing-List: git@vger.kernel.org

A complaint that has come up frequently in the past is that it is not
possible to checkout files directly into a worktree without modifying
the index. Even though this could be worked around by redirecting the
output of `git show` to overwrite files, this was not feasible if one
wanted to use patch mode.

Since `git restore` was implemented, this has since been possible using
the `--worktree` option. However, some long-time users of Git still
prefer to use `git checkout` over `git restore` and would like to see
the functionality ported over.

Teach `git checkout --worktree`, allowing users to checkout files
directly into the worktree without affecting the index.

Signed-off-by: Denton Liu <liu.denton@gmail.com>
---
 Documentation/git-checkout.txt | 22 ++++++++++-----
 builtin/checkout.c             | 17 ++++++++++++
 t/t2028-checkout-worktree.sh   | 51 ++++++++++++++++++++++++++++++++++
 t/t9902-completion.sh          |  1 +
 4 files changed, 84 insertions(+), 7 deletions(-)
 create mode 100755 t/t2028-checkout-worktree.sh

diff --git a/Documentation/git-checkout.txt b/Documentation/git-checkout.txt
index 5b697eee1b..ba9c0a900c 100644
--- a/Documentation/git-checkout.txt
+++ b/Documentation/git-checkout.txt
@@ -12,9 +12,9 @@ SYNOPSIS
 'git checkout' [-q] [-f] [-m] --detach [<branch>]
 'git checkout' [-q] [-f] [-m] [--detach] <commit>
 'git checkout' [-q] [-f] [-m] [[-b|-B|--orphan] <new_branch>] [<start_point>]
-'git checkout' [-f|--ours|--theirs|-m|--conflict=<style>] [<tree-ish>] [--] <pathspec>...
-'git checkout' [-f|--ours|--theirs|-m|--conflict=<style>] [<tree-ish>] --pathspec-from-file=<file> [--pathspec-file-nul]
-'git checkout' (-p|--patch) [<tree-ish>] [--] [<pathspec>...]
+'git checkout' [-f|--ours|--theirs|-m|--conflict=<style>] [--worktree] [<tree-ish>] [--] <pathspec>...
+'git checkout' [-f|--ours|--theirs|-m|--conflict=<style>] [--worktree] [<tree-ish>] --pathspec-from-file=<file> [--pathspec-file-nul]
+'git checkout' (-p|--patch) [--worktree] [<tree-ish>] [--] [<pathspec>...]
 
 DESCRIPTION
 -----------
@@ -79,14 +79,16 @@ be used to detach `HEAD` at the tip of the branch (`git checkout
 +
 Omitting `<branch>` detaches `HEAD` at the tip of the current branch.
 
-'git checkout' [-f|--ours|--theirs|-m|--conflict=<style>] [<tree-ish>] [--] <pathspec>...::
-'git checkout' [-f|--ours|--theirs|-m|--conflict=<style>] [<tree-ish>] --pathspec-from-file=<file> [--pathspec-file-nul]::
+'git checkout' [-f|--ours|--theirs|-m|--conflict=<style>] [--worktree] [<tree-ish>] [--] <pathspec>...::
+'git checkout' [-f|--ours|--theirs|-m|--conflict=<style>] [--worktree] [<tree-ish>] --pathspec-from-file=<file> [--pathspec-file-nul]::
 
 	Overwrite the contents of the files that match the pathspec.
 	When the `<tree-ish>` (most often a commit) is not given,
 	overwrite working tree with the contents in the index.
 	When the `<tree-ish>` is given, overwrite both the index and
-	the working tree with the contents at the `<tree-ish>`.
+	the working tree with the contents at the `<tree-ish>` unless
+	`--worktree` is given in which case _only_ the working tree is
+	overwritten.
 +
 The index may contain unmerged entries because of a previous failed merge.
 By default, if you try to check out such an entry from the index, the
@@ -96,7 +98,7 @@ specific side of the merge can be checked out of the index by
 using `--ours` or `--theirs`.  With `-m`, changes made to the working tree
 file can be discarded to re-create the original conflicted merge result.
 
-'git checkout' (-p|--patch) [<tree-ish>] [--] [<pathspec>...]::
+'git checkout' (-p|--patch) [--worktree] [<tree-ish>] [--] [<pathspec>...]::
 	This is similar to the previous mode, but lets you use the
 	interactive interface to show the "diff" output and choose which
 	hunks to use in the result.  See below for the description of
@@ -264,6 +266,12 @@ When switching branches with `--merge`, staged changes may be lost.
 	"merge" (default) and "diff3" (in addition to what is shown by
 	"merge" style, shows the original contents).
 
+-W::
+--worktree::
+	When writing contents, only modify files in the worktree. Do not
+	modify the index. This option is essentially a no-op when used
+	without a `<tree-ish>`.
+
 -p::
 --patch::
 	Interactively select hunks in the difference between the
diff --git a/builtin/checkout.c b/builtin/checkout.c
index af849c644f..a2ade85ad5 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -1741,6 +1741,20 @@ static int checkout_main(int argc, const char **argv, const char *prefix,
 		return checkout_branch(opts, &new_branch_info);
 }
 
+static int handle_worktree_opt(const struct option *opt, const char *arg, int unset)
+{
+	struct checkout_opts *opts = opt->value;
+
+	BUG_ON_OPT_NEG(unset);
+	BUG_ON_OPT_ARG(arg);
+
+	opts->checkout_index = 0;
+	opts->checkout_worktree = 1;
+
+	return 0;
+}
+
+
 int cmd_checkout(int argc, const char **argv, const char *prefix)
 {
 	struct checkout_opts opts;
@@ -1750,6 +1764,9 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 			   N_("create and checkout a new branch")),
 		OPT_STRING('B', NULL, &opts.new_branch_force, N_("branch"),
 			   N_("create/reset and checkout a branch")),
+		OPT_CALLBACK_F('W', "worktree", &opts, NULL,
+			   N_("restore the working tree (default)"),
+			   PARSE_OPT_NOARG | PARSE_OPT_NONEG, handle_worktree_opt),
 		OPT_BOOL('l', NULL, &opts.new_branch_log, N_("create reflog for new branch")),
 		OPT_BOOL(0, "guess", &opts.dwim_new_local_branch,
 			 N_("second guess 'git checkout <no-such-branch>' (default)")),
diff --git a/t/t2028-checkout-worktree.sh b/t/t2028-checkout-worktree.sh
new file mode 100755
index 0000000000..7ba36277c9
--- /dev/null
+++ b/t/t2028-checkout-worktree.sh
@@ -0,0 +1,51 @@
+#!/bin/sh
+
+test_description='checkout --worktree'
+
+. ./test-lib.sh
+
+test_expect_success setup '
+	echo first >file1 &&
+	echo file2 >file2 &&
+	git add file1 file2 &&
+	git commit -m first &&
+
+	echo second >file1 &&
+	git commit -am second &&
+	git tag tip
+'
+
+test_expect_success 'checkout --worktree on a commit' '
+	test_when_finished "git reset --hard tip" &&
+	git diff HEAD HEAD~ >expect &&
+	git checkout --worktree HEAD~ file1 &&
+	git diff >actual &&
+	test_cmp expect actual &&
+	git diff --cached --exit-code &&
+	test_cmp_rev HEAD tip
+'
+
+test_expect_success 'checkout --worktree with no commit' '
+	test_when_finished "git reset --hard tip" &&
+	echo worktree >file1 &&
+	git checkout --worktree file1 &&
+	git diff --exit-code &&
+	test_cmp_rev HEAD tip
+'
+
+test_expect_success 'checkout --no-worktree fails' '
+	test_must_fail git checkout --no-worktree
+'
+
+test_expect_success PERL 'git checkout -p --worktree' '
+	test_when_finished "git reset --hard tip" &&
+	echo changed >file2 &&
+	git diff -R --src-prefix=b/ --dst-prefix=a/ >expect &&
+	git commit -am file12 &&
+	test_write_lines n y | git checkout --worktree -p HEAD~2 &&
+	git diff >actual &&
+	test_cmp expect actual &&
+	git diff --cached --exit-code
+'
+
+test_done
diff --git a/t/t9902-completion.sh b/t/t9902-completion.sh
index 3c44af6940..1db0bb3a31 100755
--- a/t/t9902-completion.sh
+++ b/t/t9902-completion.sh
@@ -1481,6 +1481,7 @@ test_expect_success 'double dash "git checkout"' '
 	--quiet Z
 	--detach Z
 	--track Z
+	--worktree Z
 	--orphan=Z
 	--ours Z
 	--theirs Z
-- 
2.27.0.132.g321788e831