maintenance: create maintenance.strategy config

To provide an on-ramp for users to use background maintenance without
several 'git config' commands, create a 'maintenance.strategy' config
option. Currently, the only important value is 'incremental' which
assigns the following schedule:

* gc: never
* prefetch: hourly
* commit-graph: hourly
* loose-objects: daily
* incremental-repack: daily

These tasks are chosen to minimize disruptions to foreground Git
commands and use few compute resources.

The 'maintenance.strategy' is intended as a baseline that can be
customzied further by manually assigning 'maintenance.<task>.enabled'
and 'maintenance.<task>.schedule' config options, which will override
any recommendation from 'maintenance.strategy'. This operates similarly
to config options like 'feature.experimental' which operate as "meta"
config options that change default config values.

This presents a way forward for updating the 'incremental' strategy in
the future or adding new strategies. For example, a potential strategy
could be to include a 'full' strategy that runs the 'gc' task weekly
and no other tasks by default.

Helped-by: Martin Ågren <martin.agren@gmail.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 49 insertions, 0 deletions

diff --git a/t/t7900-maintenance.sh b/t/t7900-maintenance.sh
index 7715e40..7440a0e 100755
--- a/t/t7900-maintenance.sh
+++ b/t/t7900-maintenance.sh
@@ -300,6 +300,55 @@ test_expect_success '--schedule inheritance weekly -> daily -> hourly' '
 	test_subcommand git multi-pack-index write --no-progress <weekly.txt
 '
 
+test_expect_success 'maintenance.strategy inheritance' '
+	for task in commit-graph loose-objects incremental-repack
+	do
+		git config --unset maintenance.$task.schedule || return 1
+	done &&
+
+	test_when_finished git config --unset maintenance.strategy &&
+	git config maintenance.strategy incremental &&
+
+	GIT_TRACE2_EVENT="$(pwd)/incremental-hourly.txt" \
+		git maintenance run --schedule=hourly --quiet &&
+	GIT_TRACE2_EVENT="$(pwd)/incremental-daily.txt" \
+		git maintenance run --schedule=daily --quiet &&
+
+	test_subcommand git commit-graph write --split --reachable \
+		--no-progress <incremental-hourly.txt &&
+	test_subcommand ! git prune-packed --quiet <incremental-hourly.txt &&
+	test_subcommand ! git multi-pack-index write --no-progress \
+		<incremental-hourly.txt &&
+
+	test_subcommand git commit-graph write --split --reachable \
+		--no-progress <incremental-daily.txt &&
+	test_subcommand git prune-packed --quiet <incremental-daily.txt &&
+	test_subcommand git multi-pack-index write --no-progress \
+		<incremental-daily.txt &&
+
+	# Modify defaults
+	git config maintenance.commit-graph.schedule daily &&
+	git config maintenance.loose-objects.schedule hourly &&
+	git config maintenance.incremental-repack.enabled false &&
+
+	GIT_TRACE2_EVENT="$(pwd)/modified-hourly.txt" \
+		git maintenance run --schedule=hourly --quiet &&
+	GIT_TRACE2_EVENT="$(pwd)/modified-daily.txt" \
+		git maintenance run --schedule=daily --quiet &&
+
+	test_subcommand ! git commit-graph write --split --reachable \
+		--no-progress <modified-hourly.txt &&
+	test_subcommand git prune-packed --quiet <modified-hourly.txt &&
+	test_subcommand ! git multi-pack-index write --no-progress \
+		<modified-hourly.txt &&
+
+	test_subcommand git commit-graph write --split --reachable \
+		--no-progress <modified-daily.txt &&
+	test_subcommand git prune-packed --quiet <modified-daily.txt &&
+	test_subcommand ! git multi-pack-index write --no-progress \
+		<modified-daily.txt
+'
+
 test_expect_success 'register and unregister' '
 	test_when_finished git config --global --unset-all maintenance.repo &&
 	git config --global --add maintenance.repo /existing1 &&