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>

diff --git a/Documentation/config/feature.txt b/Documentation/config/feature.txt
index 8ea198a642fac5c652107597343a232d6659ccbf..545522f306eb86e10c877208ab6949debda6870a 100644 (file)
--- a/Documentation/config/feature.txt
+++ b/Documentation/config/feature.txt
@@ -4,6 +4,20 @@ feature.*::
        developer community as recommended defaults and are subject to change.
        In particular, new config options may be added with different defaults.
 
+feature.experimental::
+       Enable config options that are new to Git, and are being considered for
+       future defaults. Config settings included here may be added or removed
+       with each release, including minor version updates. These settings may
+       have unintended interactions since they are so new. Please enable this
+       setting if you are interested in providing feedback on experimental
+       features. The new default values are:
++
+* `pack.useSparse=true` uses a new algorithm when constructing a pack-file
+which can improve `git push` performance in repos with many files.
++
+* `fetch.negotiationAlgorithm=skipping` may improve fetch negotiation times by
+skipping more commits at a time, reducing the number of round trips.
+
 feature.manyFiles::
        Enable config options that optimize for repos with many files in the
        working directory. With many files, commands such as `git status` and

diff --git a/Documentation/config/fetch.txt b/Documentation/config/fetch.txt
index ba890b5884fc3496e6529cb8e1f41ad7dd9748f4..d402110638b4e465075bf1a59885563d15f190e1 100644 (file)
--- a/Documentation/config/fetch.txt
+++ b/Documentation/config/fetch.txt
@@ -59,7 +59,8 @@ fetch.negotiationAlgorithm::
        effort to converge faster, but may result in a larger-than-necessary
        packfile; The default is "default" which instructs Git to use the default algorithm
        that never skips commits (unless the server has acknowledged it or one
-       of its descendants).
+       of its descendants). If `feature.experimental` is enabled, then this
+       setting defaults to "skipping".
        Unknown values will cause 'git fetch' to error out.
 +
 See also the `--negotiation-tip` option for linkgit:git-fetch[1].

diff --git a/Documentation/config/pack.txt b/Documentation/config/pack.txt
index 9cdcfa7324784299f431d94b5237cc136aa585d1..1d66f0c992c38237dfa7def97d9b62c9803c7fc8 100644 (file)
--- a/Documentation/config/pack.txt
+++ b/Documentation/config/pack.txt
@@ -112,7 +112,8 @@ pack.useSparse::
        objects. This can have significant performance benefits when
        computing a pack to send a small change. However, it is possible
        that extra objects are added to the pack-file if the included
-       commits contain certain types of direct renames.
+       commits contain certain types of direct renames. Default is `false`
+       unless `feature.experimental` is enabled.
 
 pack.writeBitmaps (deprecated)::
        This is a deprecated synonym for `repack.writeBitmaps`.

diff --git a/fetch-negotiator.c b/fetch-negotiator.c
index d6d685cba012d6765b3998fde14b5c40fff82a96..0a1357dc9d55b34992ff5a6f65e3bdf77375465e 100644 (file)
--- a/fetch-negotiator.c
+++ b/fetch-negotiator.c
@@ -2,19 +2,20 @@
 #include "fetch-negotiator.h"
 #include "negotiator/default.h"
 #include "negotiator/skipping.h"
+#include "repository.h"
 
-void fetch_negotiator_init(struct fetch_negotiator *negotiator,
-                          const char *algorithm)
+void fetch_negotiator_init(struct repository *r,
+                          struct fetch_negotiator *negotiator)
 {
-       if (algorithm) {
-               if (!strcmp(algorithm, "skipping")) {
-                       skipping_negotiator_init(negotiator);
-                       return;
-               } else if (!strcmp(algorithm, "default")) {
-                       /* Fall through to default initialization */
-               } else {
-                       die("unknown fetch negotiation algorithm '%s'", algorithm);
-               }
+       prepare_repo_settings(r);
+       switch(r->settings.fetch_negotiation_algorithm) {
+       case FETCH_NEGOTIATION_SKIPPING:
+               skipping_negotiator_init(negotiator);
+               return;
+
+       case FETCH_NEGOTIATION_DEFAULT:
+       default:
+               default_negotiator_init(negotiator);
+               return;
        }
-       default_negotiator_init(negotiator);
 }

diff --git a/fetch-negotiator.h b/fetch-negotiator.h
index 9e3967ce6626be459ad7d8a0590240b06e7056e3..ea78868504bdcff0121c40cd40b6857df1680cfc 100644 (file)
--- a/fetch-negotiator.h
+++ b/fetch-negotiator.h
@@ -2,6 +2,7 @@
 #define FETCH_NEGOTIATOR_H
 
 struct commit;
+struct repository;
 
 /*
  * An object that supplies the information needed to negotiate the contents of
@@ -52,7 +53,7 @@ struct fetch_negotiator {
        void *data;
 };
 
-void fetch_negotiator_init(struct fetch_negotiator *negotiator,
-                          const char *algorithm);
+void fetch_negotiator_init(struct repository *r,
+                          struct fetch_negotiator *negotiator);
 
 #endif

diff --git a/fetch-pack.c b/fetch-pack.c
index 65be043f2afafdb37b4ce4d6fe8fbd3ac0eb2eaf..d81f47c07b36de586fda0840093ff259eb29650d 100644 (file)
--- a/fetch-pack.c
+++ b/fetch-pack.c
@@ -36,7 +36,6 @@ static int agent_supported;
 static int server_supports_filtering;
 static struct lock_file shallow_lock;
 static const char *alternate_shallow_file;
-static char *negotiation_algorithm;
 static struct strbuf fsck_msg_types = STRBUF_INIT;
 
 /* Remember to update object flag allocation in object.h */
@@ -892,12 +891,13 @@ static struct ref *do_fetch_pack(struct fetch_pack_args *args,
                                 struct shallow_info *si,
                                 char **pack_lockfile)
 {
+       struct repository *r = the_repository;
        struct ref *ref = copy_ref_list(orig_ref);
        struct object_id oid;
        const char *agent_feature;
        int agent_len;
        struct fetch_negotiator negotiator;
-       fetch_negotiator_init(&negotiator, negotiation_algorithm);
+       fetch_negotiator_init(r, &negotiator);
 
        sort_ref_list(&ref, ref_compare_name);
        QSORT(sought, nr_sought, cmp_ref_by_name);
@@ -911,7 +911,7 @@ static struct ref *do_fetch_pack(struct fetch_pack_args *args,
 
        if (server_supports("shallow"))
                print_verbose(args, _("Server supports %s"), "shallow");
-       else if (args->depth > 0 || is_repository_shallow(the_repository))
+       else if (args->depth > 0 || is_repository_shallow(r))
                die(_("Server does not support shallow clients"));
        if (args->depth > 0 || args->deepen_since || args->deepen_not)
                args->deepen = 1;
@@ -1379,6 +1379,7 @@ static struct ref *do_fetch_pack_v2(struct fetch_pack_args *args,
                                    struct shallow_info *si,
                                    char **pack_lockfile)
 {
+       struct repository *r = the_repository;
        struct ref *ref = copy_ref_list(orig_ref);
        enum fetch_state state = FETCH_CHECK_LOCAL;
        struct oidset common = OIDSET_INIT;
@@ -1386,7 +1387,7 @@ static struct ref *do_fetch_pack_v2(struct fetch_pack_args *args,
        int in_vain = 0;
        int haves_to_send = INITIAL_FLUSH;
        struct fetch_negotiator negotiator;
-       fetch_negotiator_init(&negotiator, negotiation_algorithm);
+       fetch_negotiator_init(r, &negotiator);
        packet_reader_init(&reader, fd[0], NULL, 0,
                           PACKET_READ_CHOMP_NEWLINE |
                           PACKET_READ_DIE_ON_ERR_PACKET);
@@ -1505,8 +1506,6 @@ static void fetch_pack_config(void)
        git_config_get_bool("repack.usedeltabaseoffset", &prefer_ofs_delta);
        git_config_get_bool("fetch.fsckobjects", &fetch_fsck_objects);
        git_config_get_bool("transfer.fsckobjects", &transfer_fsck_objects);
-       git_config_get_string("fetch.negotiationalgorithm",
-                             &negotiation_algorithm);
 
        git_config(fetch_pack_config_cb, NULL);
 }

diff --git a/repo-settings.c b/repo-settings.c
index d5bf9069f4ae31a54d53823b27f702bf66fefbee..3779b85c17532c7f51de0ae6e28208e3ca2c9c8e 100644 (file)
--- a/repo-settings.c
+++ b/repo-settings.c
@@ -36,16 +36,29 @@ void prepare_repo_settings(struct repository *r)
                free(strval);
        }
 
+       if (!repo_config_get_string(r, "fetch.negotiationalgorithm", &strval)) {
+               if (!strcasecmp(strval, "skipping"))
+                       r->settings.fetch_negotiation_algorithm = FETCH_NEGOTIATION_SKIPPING;
+               else
+                       r->settings.fetch_negotiation_algorithm = FETCH_NEGOTIATION_DEFAULT;
+       }
+
        if (!repo_config_get_bool(r, "pack.usesparse", &value))
                r->settings.pack_use_sparse = value;
        if (!repo_config_get_bool(r, "feature.manyfiles", &value) && value) {
                UPDATE_DEFAULT_BOOL(r->settings.index_version, 4);
                UPDATE_DEFAULT_BOOL(r->settings.core_untracked_cache, UNTRACKED_CACHE_WRITE);
        }
+       if (!repo_config_get_bool(r, "feature.experimental", &value) && value) {
+               UPDATE_DEFAULT_BOOL(r->settings.pack_use_sparse, 1);
+               UPDATE_DEFAULT_BOOL(r->settings.fetch_negotiation_algorithm, FETCH_NEGOTIATION_SKIPPING);
+       }
 
        /* Hack for test programs like test-dump-untracked-cache */
        if (ignore_untracked_cache_config)
                r->settings.core_untracked_cache = UNTRACKED_CACHE_KEEP;
        else
                UPDATE_DEFAULT_BOOL(r->settings.core_untracked_cache, UNTRACKED_CACHE_KEEP);
+
+       UPDATE_DEFAULT_BOOL(r->settings.fetch_negotiation_algorithm, FETCH_NEGOTIATION_DEFAULT);
 }

diff --git a/repository.h b/repository.h
index cf7ff0778c853b55fff917959797de579b4a0412..4da275e73fac1a97c39109b7bf31ae01f20e0730 100644 (file)
--- 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 {

diff --git a/t/t5552-skipping-fetch-negotiator.sh b/t/t5552-skipping-fetch-negotiator.sh
index 8a14be51a13280d3fccd340c027cd5f20bb941a5..f70cbcc9cabf6499de57529cbfa095ed9eff73e3 100755 (executable)
--- a/t/t5552-skipping-fetch-negotiator.sh
+++ b/t/t5552-skipping-fetch-negotiator.sh
@@ -60,29 +60,6 @@ test_expect_success 'commits with no parents are sent regardless of skip distanc
        have_not_sent c6 c4 c3
 '
 
-test_expect_success 'unknown fetch.negotiationAlgorithm values error out' '
-       rm -rf server client trace &&
-       git init server &&
-       test_commit -C server to_fetch &&
-
-       git init client &&
-       test_commit -C client on_client &&
-       git -C client checkout on_client &&
-
-       test_config -C client fetch.negotiationAlgorithm invalid &&
-       test_must_fail git -C client fetch "$(pwd)/server" 2>err &&
-       test_i18ngrep "unknown fetch negotiation algorithm" err &&
-
-       # Explicit "default" value
-       test_config -C client fetch.negotiationAlgorithm default &&
-       git -C client -c fetch.negotiationAlgorithm=default fetch "$(pwd)/server" &&
-
-       # Implementation detail: If there is nothing to fetch, we will not error out
-       test_config -C client fetch.negotiationAlgorithm invalid &&
-       git -C client fetch "$(pwd)/server" 2>err &&
-       test_i18ngrep ! "unknown fetch negotiation algorithm" err
-'
-
 test_expect_success 'when two skips collide, favor the larger one' '
        rm -rf server client trace &&
        git init server &&