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, 55 insertions, 0 deletions

diff --git a/third_party/git/Documentation/RelNotes/2.25.1.txt b/third_party/git/Documentation/RelNotes/2.25.1.txt
new file mode 100644
index 000000000000..cd869b02bbbc
--- /dev/null
+++ b/third_party/git/Documentation/RelNotes/2.25.1.txt
@@ -0,0 +1,55 @@
+Git 2.25.1 Release Notes
+========================
+
+Fixes since v2.25
+-----------------
+
+ * "git commit" gives output similar to "git status" when there is
+   nothing to commit, but without honoring the advise.statusHints
+   configuration variable, which has been corrected.
+
+ * has_object_file() said "no" given an object registered to the
+   system via pretend_object_file(), making it inconsistent with
+   read_object_file(), causing lazy fetch to attempt fetching an
+   empty tree from promisor remotes.
+
+ * The code that tries to skip over the entries for the paths in a
+   single directory using the cache-tree was not careful enough
+   against corrupt index file.
+
+ * Complete an update to tutorial that encourages "git switch" over
+   "git checkout" that was done only half-way.
+
+ * Reduce unnecessary round-trip when running "ls-remote" over the
+   stateless RPC mechanism.
+
+ * "git restore --staged" did not correctly update the cache-tree
+   structure, resulting in bogus trees to be written afterwards, which
+   has been corrected.
+
+ * The code recently added to move to the entry beyond the ones in the
+   same directory in the index in the sparse-cone mode did not count
+   the number of entries to skip over incorrectly, which has been
+   corrected.
+
+ * Work around test breakages caused by custom regex engine used in
+   libasan, when address sanitizer is used with more recent versions
+   of gcc and clang.
+
+ * "git fetch --refmap=" option has got a better documentation.
+
+ * Corner case bugs in "git clean" that stems from a (necessarily for
+   performance reasons) awkward calling convention in the directory
+   enumeration API has been corrected.
+
+ * "git grep --no-index" should not get affected by the contents of
+   the .gitmodules file but when "--recurse-submodules" is given or
+   the "submodule.recurse" variable is set, it did.  Now these
+   settings are ignored in the "--no-index" mode.
+
+ * Technical details of the bundle format has been documented.
+
+ * Unhelpful warning messages during documentation build have been
+   squelched.
+
+Also contains various documentation updates, code clean-ups and minor fixups.