merge(3p/git): Merge git subtree at v2.29.2 r/1890

This also bumps the stable nixpkgs to 20.09 as of 2020-11-21, because
there is some breakage in the git build related to the netrc
credentials helper which someone has taken care of in nixpkgs.

The stable channel is not used for anything other than git, so this
should be fine.

Change-Id: I3575a19dab09e1e9556cf8231d717de9890484fb

1 files changed, 33 insertions, 7 deletions

diff --git a/third_party/git/Documentation/config/fetch.txt b/third_party/git/Documentation/config/fetch.txt
index ba890b5884fc..6af6f5edb278 100644
--- a/third_party/git/Documentation/config/fetch.txt
+++ b/third_party/git/Documentation/config/fetch.txt
@@ -1,11 +1,14 @@
 fetch.recurseSubmodules::
-	This option can be either set to a boolean value or to 'on-demand'.
+	This option controls whether `git fetch` (and the underlying fetch
+	in `git pull`) will recursively fetch into populated submodules.
+	This option can be set either to a boolean value or to 'on-demand'.
 	Setting it to a boolean changes the behavior of fetch and pull to
-	unconditionally recurse into submodules when set to true or to not
-	recurse at all when set to false. When set to 'on-demand' (the default
-	value), fetch and pull will only recurse into a populated submodule
-	when its superproject retrieves a commit that updates the submodule's
+	recurse unconditionally into submodules when set to true or to not
+	recurse at all when set to false. When set to 'on-demand', fetch and
+	pull will only recurse into a populated submodule when its
+	superproject retrieves a commit that updates the submodule's
 	reference.
+	Defaults to 'on-demand', or to the value of 'submodule.recurse' if set.
 
 fetch.fsckObjects::
 	If it is set to true, git-fetch-pack will check all fetched
@@ -57,9 +60,13 @@ fetch.negotiationAlgorithm::
 	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; The default is "default" which instructs Git to use the default algorithm
+	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).
+	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].
@@ -68,3 +75,22 @@ fetch.showForcedUpdates::
 	Set to false to enable `--no-show-forced-updates` in
 	linkgit:git-fetch[1] and linkgit:git-pull[1] commands.
 	Defaults to true.
+
+fetch.parallel::
+	Specifies the maximal number of fetch operations to be run in parallel
+	at a time (submodules, or remotes when the `--multiple` option of
+	linkgit:git-fetch[1] is in effect).
++
+A value of 0 will give some reasonable default. If unset, it defaults to 1.
++
+For submodules, this setting can be overridden using the `submodule.fetchJobs`
+config setting.
+
+fetch.writeCommitGraph::
+	Set to true to write a commit-graph after every `git fetch` command
+	that downloads a pack-file from a remote. Using the `--split` option,
+	most executions will create a very small commit-graph file on top of
+	the existing commit-graph file(s). Occasionally, these files will
+	merge and the write may take longer. Having an updated commit-graph
+	file helps performance of many Git commands, including `git merge-base`,
+	`git push -f`, and `git log --graph`. Defaults to false.