From cac6a524a27389d15496a550fc455d83cf014292 Mon Sep 17 00:00:00 2001
From: Kevin Willford <kewillf@microsoft.com>
Date: Tue, 24 Jan 2017 17:38:59 +0100
Subject: [PATCH] gvfs: add the feature to skip writing the index' SHA-1

This takes a substantial amount of time, and if the user is reasonably
sure that the files' integrity is not compromised, that time can be saved.

Git no longer verifies the SHA-1 by default, anyway.

Signed-off-by: Kevin Willford <kewillf@microsoft.com>

Update for 2023-02-27: This feature was upstreamed as the index.skipHash
config option. This resulted in some changes to the struct and some of
the setup code. In particular, the config reading was moved to
prepare_repo_settings(), so the core.gvfs bit check was moved there,
too.

Signed-off-by: Derrick Stolee <derrickstolee@github.com>
---
 Documentation/config/core.txt         | 10 +++++++++-
 gvfs.h                                |  6 ++++++
 repo-settings.c                       |  8 ++++++++
 t/t1016-read-tree-skip-sha-on-read.sh | 22 ++++++++++++++++++++++
 4 files changed, 45 insertions(+), 1 deletion(-)
 create mode 100755 t/t1016-read-tree-skip-sha-on-read.sh

diff --git a/Documentation/config/core.txt b/Documentation/config/core.txt
index 5fa9e77214392e..93ffdee63f4e36 100644
--- a/Documentation/config/core.txt
+++ b/Documentation/config/core.txt
@@ -729,7 +729,15 @@ core.multiPackIndex::
 	information. Defaults to true.
 
 core.gvfs::
-	Enable the features needed for GVFS.
+	Enable the features needed for GVFS.  This value can be set to true
+	to indicate all features should be turned on or the bit values listed
+	below can be used to turn on specific features.
++
+--
+	GVFS_SKIP_SHA_ON_INDEX::
+		Bit value 1
+		Disables the calculation of the sha when writing the index
+--
 
 core.sparseCheckout::
 	Enable "sparse checkout" feature. See linkgit:git-sparse-checkout[1]
diff --git a/gvfs.h b/gvfs.h
index 011185dea93734..c75991530fa1fa 100644
--- a/gvfs.h
+++ b/gvfs.h
@@ -7,6 +7,12 @@
  * used for GVFS functionality
  */
 
+
+/*
+ * The list of bits in the core_gvfs setting
+ */
+#define GVFS_SKIP_SHA_ON_INDEX                      (1 << 0)
+
 void gvfs_load_config_value(const char *value);
 int gvfs_config_is_set(int mask);
 
diff --git a/repo-settings.c b/repo-settings.c
index 9f711c87753c1b..fb76ee4c69ca7e 100644
--- a/repo-settings.c
+++ b/repo-settings.c
@@ -4,6 +4,7 @@
 #include "midx.h"
 #include "fsmonitor-ipc.h"
 #include "fsmonitor-settings.h"
+#include "gvfs.h"
 
 static void repo_cfg_bool(struct repository *r, const char *key, int *dest,
 			  int def)
@@ -94,6 +95,13 @@ void prepare_repo_settings(struct repository *r)
 		      r->settings.pack_use_bitmap_boundary_traversal);
 	repo_cfg_bool(r, "core.usereplacerefs", &r->settings.read_replace_refs, 1);
 
+	/*
+	 * For historical compatibility reasons, enable index.skipHash based
+	 * on a bit in core.gvfs.
+	 */
+	if (gvfs_config_is_set(GVFS_SKIP_SHA_ON_INDEX))
+		r->settings.index_skip_hash = 1;
+
 	/*
 	 * The GIT_TEST_MULTI_PACK_INDEX variable is special in that
 	 * either it *or* the config sets
diff --git a/t/t1016-read-tree-skip-sha-on-read.sh b/t/t1016-read-tree-skip-sha-on-read.sh
new file mode 100755
index 00000000000000..5b76a80a0020dc
--- /dev/null
+++ b/t/t1016-read-tree-skip-sha-on-read.sh
@@ -0,0 +1,22 @@
+#!/bin/sh
+
+test_description='check that read-tree works with core.gvfs config value'
+
+. ./test-lib.sh
+. "$TEST_DIRECTORY"/lib-read-tree.sh
+
+test_expect_success setup '
+	echo one >a &&
+	git add a &&
+	git commit -m initial
+'
+test_expect_success 'read-tree without core.gvsf' '
+	read_tree_u_must_succeed -m -u HEAD
+'
+
+test_expect_success 'read-tree with core.gvfs set to 1' '
+	git config core.gvfs 1 &&
+	read_tree_u_must_succeed -m -u HEAD
+'
+
+test_done