[v4,3/3] repo-settings: rename the traditional default fetch.negotiationAlgorithm

Commit Message

Elijah Newren Feb. 2, 2022, 3:42 a.m. UTC

From: Elijah Newren <[e-mail]>

Give the traditional default fetch.negotiationAlgorithm the name
'consecutive'.  Also allow a choice of 'default' to have Git decide
between the choices (currently, picking 'skipping' if
feature.experimental is true and 'consecutive' otherwise).  Update the
documentation accordingly.

Signed-off-by: Elijah Newren <[e-mail]>
---
 Documentation/config/fetch.txt | 25 +++++++++++++------------
 fetch-negotiator.c             |  2 +-
 repo-settings.c                |  7 +++++--
 repository.h                   |  2 +-
 t/t5500-fetch-pack.sh          |  2 +-
 5 files changed, 21 insertions(+), 17 deletions(-)

Comments

Junio C Hamano Feb. 2, 2022, 5:50 p.m. UTC | #1

"Elijah Newren via GitGitGadget" <[e-mail]> writes:

> diff --git a/repo-settings.c b/repo-settings.c
> index 41e1c30845f..b4fbd16cdcc 100644
> --- a/repo-settings.c
> +++ b/repo-settings.c
> @@ -26,7 +26,7 @@ void prepare_repo_settings(struct repository *r)
>  	/* Defaults */
>  	r->settings.index_version = -1;
>  	r->settings.core_untracked_cache = UNTRACKED_CACHE_KEEP;
> -	r->settings.fetch_negotiation_algorithm = FETCH_NEGOTIATION_DEFAULT;
> +	r->settings.fetch_negotiation_algorithm = FETCH_NEGOTIATION_CONSECUTIVE;
>  
>  	/* Booleans config or default, cascades to other settings */
>  	repo_cfg_bool(r, "feature.manyfiles", &manyfiles, 0);
> @@ -81,12 +81,15 @@ void prepare_repo_settings(struct repository *r)
>  	}
>  
>  	if (!repo_config_get_string(r, "fetch.negotiationalgorithm", &strval)) {
> +		int fetch_default = r->settings.fetch_negotiation_algorithm;
>  		if (!strcasecmp(strval, "skipping"))
>  			r->settings.fetch_negotiation_algorithm = FETCH_NEGOTIATION_SKIPPING;
>  		else if (!strcasecmp(strval, "noop"))
>  			r->settings.fetch_negotiation_algorithm = FETCH_NEGOTIATION_NOOP;
> +		else if (!strcasecmp(strval, "consecutive"))
> +			r->settings.fetch_negotiation_algorithm = FETCH_NEGOTIATION_CONSECUTIVE;
>  		else if (!strcasecmp(strval, "default"))
> -			r->settings.fetch_negotiation_algorithm = FETCH_NEGOTIATION_DEFAULT;
> +			r->settings.fetch_negotiation_algorithm = fetch_default;
>  		else
>  			die("unknown fetch negotiation algorithm '%s'", strval);
>  	}

This 

    - set the default to whatever experimental says
    - parse the configuration and set it 
      - to the specified value unless it is DEFAULT
      - to the value the experimental bit set as the default otherwise

certainly works, even though I find it a bit convoluted and
backwards.  I have slight preference to "if the user says 'default',
hold onto it as a symbolic 'default' setting, and resolve it to a
concrete value at the very end" pattern, which tends to handle the
"reverting to default" case better.

There is the "manyfiles" precedent that sets index.version and
core.untrackedCache irreversibly nearby, and I am sympathetic to
whoever added the fetch_negotiation_algorithm support (it probably
is not you, I am guessing) by mimicking it, so I am OK with the
version posted as-is.

Thanks.

Patch

diff --git a/Documentation/config/fetch.txt b/Documentation/config/fetch.txt
index 63748c02b72..cd65d236b43 100644
--- a/Documentation/config/fetch.txt
+++ b/Documentation/config/fetch.txt
@@ -56,18 +56,19 @@  fetch.output::
 	OUTPUT in linkgit:git-fetch[1] for detail.
 
 fetch.negotiationAlgorithm::
-	Control how information about the commits in the local repository is
-	sent when negotiating the contents of the packfile to be sent by the
-	server. Set to "skipping" to use an algorithm that skips commits in an
-	effort to converge faster, but may result in a larger-than-necessary
-	packfile; or set to "noop" to not send any information at all, which
-	will almost certainly result in a larger-than-necessary packfile, but
-	will skip the negotiation step.
-	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). If `feature.experimental` is enabled, then this
-	setting defaults to "skipping".
-	Unknown values will cause 'git fetch' to error out.
+	Control how information about the commits in the local repository
+	is sent when negotiating the contents of the packfile to be sent by
+	the server.  Set to "consecutive" to use an algorithm that walks
+	over consecutive commits checking each one.  Set to "skipping" to
+	use an algorithm that skips commits in an effort to converge
+	faster, but may result in a larger-than-necessary packfile; or set
+	to "noop" to not send any information at all, which will almost
+	certainly result in a larger-than-necessary packfile, but will skip
+	the negotiation step.  Set to "default" to override settings made
+	previously and use the default behaviour.  The default is normally
+	"consecutive", but if `feature.experimental` is true, then the
+	default is "skipping".  Unknown values will cause 'git fetch' to
+	error out.
 +
 See also the `--negotiate-only` and `--negotiation-tip` options to
 linkgit:git-fetch[1].
diff --git a/fetch-negotiator.c b/fetch-negotiator.c
index 273390229fe..874797d767b 100644
--- a/fetch-negotiator.c
+++ b/fetch-negotiator.c
@@ -18,7 +18,7 @@  void fetch_negotiator_init(struct repository *r,
 		noop_negotiator_init(negotiator);
 		return;
 
-	case FETCH_NEGOTIATION_DEFAULT:
+	case FETCH_NEGOTIATION_CONSECUTIVE:
 		default_negotiator_init(negotiator);
 		return;
 	}
diff --git a/repo-settings.c b/repo-settings.c
index 41e1c30845f..b4fbd16cdcc 100644
--- a/repo-settings.c
+++ b/repo-settings.c
@@ -26,7 +26,7 @@  void prepare_repo_settings(struct repository *r)
 	/* Defaults */
 	r->settings.index_version = -1;
 	r->settings.core_untracked_cache = UNTRACKED_CACHE_KEEP;
-	r->settings.fetch_negotiation_algorithm = FETCH_NEGOTIATION_DEFAULT;
+	r->settings.fetch_negotiation_algorithm = FETCH_NEGOTIATION_CONSECUTIVE;
 
 	/* Booleans config or default, cascades to other settings */
 	repo_cfg_bool(r, "feature.manyfiles", &manyfiles, 0);
@@ -81,12 +81,15 @@  void prepare_repo_settings(struct repository *r)
 	}
 
 	if (!repo_config_get_string(r, "fetch.negotiationalgorithm", &strval)) {
+		int fetch_default = r->settings.fetch_negotiation_algorithm;
 		if (!strcasecmp(strval, "skipping"))
 			r->settings.fetch_negotiation_algorithm = FETCH_NEGOTIATION_SKIPPING;
 		else if (!strcasecmp(strval, "noop"))
 			r->settings.fetch_negotiation_algorithm = FETCH_NEGOTIATION_NOOP;
+		else if (!strcasecmp(strval, "consecutive"))
+			r->settings.fetch_negotiation_algorithm = FETCH_NEGOTIATION_CONSECUTIVE;
 		else if (!strcasecmp(strval, "default"))
-			r->settings.fetch_negotiation_algorithm = FETCH_NEGOTIATION_DEFAULT;
+			r->settings.fetch_negotiation_algorithm = fetch_default;
 		else
 			die("unknown fetch negotiation algorithm '%s'", strval);
 	}
diff --git a/repository.h b/repository.h
index 2b5cf97f31e..ca837cb9e91 100644
--- a/repository.h
+++ b/repository.h
@@ -20,7 +20,7 @@  enum untracked_cache_setting {
 };
 
 enum fetch_negotiation_setting {
-	FETCH_NEGOTIATION_DEFAULT,
+	FETCH_NEGOTIATION_CONSECUTIVE,
 	FETCH_NEGOTIATION_SKIPPING,
 	FETCH_NEGOTIATION_NOOP,
 };
diff --git a/t/t5500-fetch-pack.sh b/t/t5500-fetch-pack.sh
index 41ea9f25de6..ee6d2dde9f3 100755
--- a/t/t5500-fetch-pack.sh
+++ b/t/t5500-fetch-pack.sh
@@ -968,7 +968,7 @@  test_expect_success 'use ref advertisement to prune "have" lines sent' '
 test_expect_success 'same as last but with config overrides' '
 	test_negotiation_algorithm_default \
 		-c feature.experimental=true \
-		-c fetch.negotiationAlgorithm=default
+		-c fetch.negotiationAlgorithm=consecutive
 '
 
 test_expect_success 'ensure bogus fetch.negotiationAlgorithm yields error' '