repo-settings: create feature.experimental setting

The 'feature.experimental' setting includes config options that are
not committed to become defaults, but could use additional testing.

Update the following config settings to take new defaults, and to
use the repo_settings struct if not already using them:

* 'pack.useSparse=true'

* 'fetch.negotiationAlgorithm=skipping'

In the case of fetch.negotiationAlgorithm, the existing logic
would load the config option only when about to use the setting,
so had a die() statement on an unknown string value. This is
removed as now the config is parsed under prepare_repo_settings().
In general, this die() is probably misplaced and not valuable.
A test was removed that checked this die() statement executed.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/repository.h b/repository.h
index cf7ff0778c..4da275e73f 100644
--- a/repository.h
+++ b/repository.h
@@ -18,6 +18,13 @@ enum untracked_cache_setting {
 	UNTRACKED_CACHE_WRITE = 2
 };
 
+enum fetch_negotiation_setting {
+	FETCH_NEGOTIATION_UNSET = -1,
+	FETCH_NEGOTIATION_NONE = 0,
+	FETCH_NEGOTIATION_DEFAULT = 1,
+	FETCH_NEGOTIATION_SKIPPING = 2,
+};
+
 struct repo_settings {
 	int initialized;
 
@@ -28,6 +35,7 @@ struct repo_settings {
 	enum untracked_cache_setting core_untracked_cache;
 
 	int pack_use_sparse;
+	enum fetch_negotiation_setting fetch_negotiation_algorithm;
 };
 
 struct repository {