[PATCH 3/3] commit-graph: Use commit-graph by default

["Derrick Stolee via GitGitGadget" <gitgitgadget@gmail.com>]

From: Derrick Stolee <dstolee@microsoft.com>

The config setting "core.commitGraph" enables using the commit-graph
file to accelerate commit walks through parsing speed and generation
numbers. The setting "gc.writeCommitGraph" enables writing the
commit-graph file on every non-trivial 'git gc' operation. Together,
they help users automatically improve their performance.

By setting these config variables to true by default, we make the
commit-graph feature an "opt-out" feature instead of "opt-in".

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
---
 Documentation/config.txt | 4 ++--
 builtin/gc.c             | 2 +-
 commit-graph.c           | 6 +++---
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/Documentation/config.txt b/Documentation/config.txt
index f6f4c21a54..dc5ee7c145 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -923,7 +923,7 @@ the `GIT_NOTES_REF` environment variable.  See linkgit:git-notes[1].
 
 core.commitGraph::
 	If true, then git will read the commit-graph file (if it exists)
-	to parse the graph structure of commits. Defaults to false. See
+	to parse the graph structure of commits. Defaults to true. See
 	linkgit:git-commit-graph[1] for more information.
 
 core.useReplaceRefs::
@@ -1639,7 +1639,7 @@ gc.writeCommitGraph::
 	If true, then gc will rewrite the commit-graph file when
 	linkgit:git-gc[1] is run. When using linkgit:git-gc[1]
 	'--auto' the commit-graph will be updated if housekeeping is
-	required. Default is false. See linkgit:git-commit-graph[1]
+	required. Default is true. See linkgit:git-commit-graph[1]
 	for details.
 
 gc.logExpiry::
diff --git a/builtin/gc.c b/builtin/gc.c
index 871a56f1c5..77e7413f94 100644
--- a/builtin/gc.c
+++ b/builtin/gc.c
@@ -41,7 +41,7 @@ static int aggressive_depth = 50;
 static int aggressive_window = 250;
 static int gc_auto_threshold = 6700;
 static int gc_auto_pack_limit = 50;
-static int gc_write_commit_graph;
+static int gc_write_commit_graph = 1;
 static int detach_auto = 1;
 static timestamp_t gc_log_expire_time;
 static const char *gc_log_expire = "1.day.ago";
diff --git a/commit-graph.c b/commit-graph.c
index a686758603..a459272466 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -232,15 +232,15 @@ static int prepare_commit_graph(struct repository *r)
 {
 	struct alternate_object_database *alt;
 	char *obj_dir;
-	int config_value;
+	int config_value = 1;
 
 	if (r->objects->commit_graph_attempted)
 		return !!r->objects->commit_graph;
 	r->objects->commit_graph_attempted = 1;
 
+	repo_config_get_bool(r, "core.commitgraph", &config_value);
 	if (!git_env_bool(GIT_TEST_COMMIT_GRAPH, 0) &&
-	    (repo_config_get_bool(r, "core.commitgraph", &config_value) ||
-	    !config_value))
+	    !config_value)
 		/*
 		 * This repository is not configured to use commit graphs, so
 		 * do not load one. (But report commit_graph_attempted anyway
-- 
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