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, 13 insertions, 8 deletions

diff --git a/third_party/git/Documentation/git-pack-objects.txt b/third_party/git/Documentation/git-pack-objects.txt
index fecdf2600cc9..54d715ead137 100644
--- a/third_party/git/Documentation/git-pack-objects.txt
+++ b/third_party/git/Documentation/git-pack-objects.txt
@@ -14,7 +14,7 @@ SYNOPSIS
 	[--local] [--incremental] [--window=<n>] [--depth=<n>]
 	[--revs [--unpacked | --all]] [--keep-pack=<pack-name>]
 	[--stdout [--filter=<filter-spec>] | base-name]
-	[--shallow] [--keep-true-parents] [--sparse] < object-list
+	[--shallow] [--keep-true-parents] [--[no-]sparse] < object-list
 
 
 DESCRIPTION
@@ -196,14 +196,16 @@ depth is 4095.
 	Add --no-reuse-object if you want to force a uniform compression
 	level on all data no matter the source.
 
---sparse::
-	Use the "sparse" algorithm to determine which objects to include in
+--[no-]sparse::
+	Toggle the "sparse" algorithm to determine which objects to include in
 	the pack, when combined with the "--revs" option. This algorithm
 	only walks trees that appear in paths that introduce new 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.
+	certain types of direct renames. If this option is not included,
+	it defaults to the value of `pack.useSparse`, which is true unless
+	otherwise specified.
 
 --thin::
 	Create a "thin" pack by omitting the common objects between a
@@ -268,15 +270,18 @@ So does `git bundle` (see linkgit:git-bundle[1]) when it creates a bundle.
 	This option specifies how missing objects are handled.
 +
 The form '--missing=error' requests that pack-objects stop with an error if
-a missing object is encountered.  This is the default action.
+a missing object is encountered.  If the repository is a partial clone, an
+attempt to fetch missing objects will be made before declaring them missing.
+This is the default action.
 +
 The form '--missing=allow-any' will allow object traversal to continue
-if a missing object is encountered.  Missing objects will silently be
-omitted from the results.
+if a missing object is encountered.  No fetch of a missing object will occur.
+Missing objects will silently be omitted from the results.
 +
 The form '--missing=allow-promisor' is like 'allow-any', but will only
 allow object traversal to continue for EXPECTED promisor missing objects.
-Unexpected missing object will raise an error.
+No fetch of a missing object will occur.  An unexpected missing object will
+raise an error.
 
 --exclude-promisor-objects::
 	Omit objects that are known to be in the promisor remote.  (This