From:   Derrick Stolee <dstolee@microsoft.com>
To:     "git@vger.kernel.org" <git@vger.kernel.org>
CC:     "sbeller@google.com" <sbeller@google.com>,
        "jnareb@gmail.com" <jnareb@gmail.com>,
        "stolee@gmail.com" <stolee@gmail.com>,
        Derrick Stolee <dstolee@microsoft.com>
Subject: [RFC PATCH 4/6] commit-graph: avoid writing when repo is shallow
Thread-Topic: [RFC PATCH 4/6] commit-graph: avoid writing when repo is shallow
Thread-Index: AQHT+QaSMrtyWVuHHkSMp8VVuNdvlg==
Date:   Thu, 31 May 2018 17:41:14 +0000
Message-ID: <20180531174024.124488-5-dstolee@microsoft.com>
References: <20180531174024.124488-1-dstolee@microsoft.com>
In-Reply-To: <20180531174024.124488-1-dstolee@microsoft.com>
Accept-Language: en-US
Content-Language: en-US
x-ms-exchange-messagesentrepresentingtype: 1
x-originating-ip: [2001:4898:8010:0:eb4a:5dff:fe0f:730f]
x-ms-publictraffictype: Email
x-microsoft-exchange-diagnostics: 1;BL0PR2101MB0996;7:IlePr44N6Ho4ueLVfHfw5gZN9EvBGCDabd6OYGxdykOj7chuRn5pi/1Wpo7y80wkPtdDcc3HhvgQ55mS8+GgNk4qplJP6PpXHL4wIz4c64XSO4skcDiWzRoZo2zWZRlnZcYEg3FN5RKNfI9nrkWW81ljVtSJPEsxJ2qlUx3TbAieSVEP2mwK3udlBXcJBUOlAwwvcpUagRagTJqFdDN+XaXXVH658cITAVpdoCS5IQHcJ2V+PeWRMQjgA/NAbSbC;20:J2fxBvVlQt45cktwa8GYggGY2zP7MCPtJGyb9+U7zZS5m6umGk3gUSTSpBv6vaqSQ0FlHikupBM4sl2i4WeYEVUD3KosfgAe19LrWBm++Auco6HO8mXXI5T05gIXxWCJA0kOZa/oitJaSCFtlVffZY3RCOuRcRDsUObT8mG59wc=
x-ms-office365-filtering-ht: Tenant
x-microsoft-antispam: UriScan:;BCL:0;PCL:0;RULEID:(7020095)(4652020)(5600026)(48565401081)(4534165)(4627221)(201703031133081)(201702281549075)(2017052603328)(7193020);SRVR:BL0PR2101MB0996;
x-ms-traffictypediagnostic: BL0PR2101MB0996:
authentication-results: spf=none (sender IP is )
 smtp.mailfrom=dstolee@microsoft.com; 
x-microsoft-antispam-prvs: <BL0PR2101MB09966D9CB6A582E86D6E1D80A1630@BL0PR2101MB0996.namprd21.prod.outlook.com>
x-exchange-antispam-report-test: UriScan:(28532068793085)(89211679590171)(35073007944872);
x-ms-exchange-senderadcheck: 1
x-exchange-antispam-report-cfa-test: BCL:0;PCL:0;RULEID:(8211001083)(6040522)(2401047)(5005006)(8121501046)(93006095)(93001095)(3002001)(10201501046)(3231254)(2018427008)(944501410)(52105095)(6055026)(149027)(150027)(6041310)(201703131423095)(201702281528075)(20161123555045)(201703061421075)(201703061406153)(20161123564045)(20161123558120)(20161123562045)(20161123560045)(6072148)(201708071742011)(7699016);SRVR:BL0PR2101MB0996;BCL:0;PCL:0;RULEID:;SRVR:BL0PR2101MB0996;
x-forefront-prvs: 06891E23FB
x-forefront-antispam-report: SFV:NSPM;SFS:(10019020)(396003)(39380400002)(346002)(366004)(39860400002)(376002)(199004)(189003)(39060400002)(22452003)(6436002)(25786009)(316002)(10090500001)(4326008)(86362001)(107886003)(3660700001)(3280700002)(5640700003)(97736004)(8936002)(478600001)(53936002)(81166006)(1730700003)(81156014)(2906002)(46003)(6486002)(6916009)(10290500003)(54906003)(8676002)(68736007)(5660300001)(1076002)(2616005)(99286004)(476003)(6116002)(52116002)(6512007)(486006)(36756003)(186003)(2501003)(446003)(2900100001)(7736002)(76176011)(5250100002)(11346002)(14454004)(305945005)(102836004)(106356001)(59450400001)(2351001)(386003)(105586002)(86612001)(6506007)(22906009)(217873001);DIR:OUT;SFP:1102;SCL:1;SRVR:BL0PR2101MB0996;H:BL0PR2101MB1011.namprd21.prod.outlook.com;FPR:;SPF:None;LANG:en;PTR:InfoNoRecords;A:1;MX:1;
received-spf: None (protection.outlook.com: microsoft.com does not designate
 permitted sender hosts)
x-microsoft-antispam-message-info: 6VWSSfJjawPKxeCVXnXCyMm0p8meFlZgWLjG+zo6/nqIO39J9Wlxhz76ThPX6TbaQnzhldCIgQR5nyhIJ1kIQOyZoRngBDL+iGCpIZS0RvxTusBSRSwqTfYVZ4pSyDrzIGvgwhHj9LesuUh76DZuWdTJrlOQvJBvwaM7zXXv/EdYQhLoTcobIuPAT4TTlhwx
spamdiagnosticoutput: 1:99
spamdiagnosticmetadata: NSPM
Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-MS-Office365-Filtering-Correlation-Id: 64bb5aaf-8a09-4e3e-9598-08d5c71db4b5
X-OriginatorOrg: microsoft.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 64bb5aaf-8a09-4e3e-9598-08d5c71db4b5
X-MS-Exchange-CrossTenant-originalarrivaltime: 31 May 2018 17:41:14.8040
 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: 72f988bf-86f1-41af-91ab-2d7cd011db47
X-MS-Exchange-Transport-CrossTenantHeadersStamped: BL0PR2101MB0996
Sender: git-owner@vger.kernel.org
Precedence: bulk
List-ID: <git.vger.kernel.org>
X-Mailing-List: git@vger.kernel.org

Shallow clones do not interact well with the commit-graph feature for
several reasons. Instead of doing the hard thing to fix those
interactions, instead prevent reading or writing a commit-graph file for
shallow repositories.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
---
 commit-graph.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/commit-graph.c b/commit-graph.c
index 95af4ed519..80e377b90f 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -208,6 +208,9 @@ static void prepare_commit_graph(void)
 		return;
 	prepare_commit_graph_run_once =3D 1;
=20
+	if (is_repository_shallow())
+		return;
+
 	obj_dir =3D get_object_directory();
 	prepare_commit_graph_one(obj_dir);
 	prepare_alt_odb();
@@ -711,6 +714,15 @@ void write_commit_graph(const char *obj_dir,
 	int num_extra_edges;
 	struct commit_list *parent;
=20
+	/*
+	 * Shallow clones are not supproted, as they create bad
+	 * generation skips as they are un-shallowed.
+	 */
+	if (is_repository_shallow()) {
+		warning("writing a commit-graph in a shallow repository is not supported=
");
+		return;
+	}
+
 	oids.nr =3D 0;
 	oids.alloc =3D approximate_object_count() / 4;
=20
--=20
2.16.2.338.gcfe06ae955