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, 60 insertions, 0 deletions

diff --git a/third_party/git/Documentation/RelNotes/2.25.2.txt b/third_party/git/Documentation/RelNotes/2.25.2.txt
new file mode 100644
index 0000000000..303c53a17f
--- /dev/null
+++ b/third_party/git/Documentation/RelNotes/2.25.2.txt
@@ -0,0 +1,60 @@
+Git 2.25.2 Release Notes
+========================
+
+Fixes since v2.25.1
+-------------------
+
+ * Minor bugfixes to "git add -i" that has recently been rewritten in C.
+
+ * An earlier update to show the location of working tree in the error
+   message did not consider the possibility that a git command may be
+   run in a bare repository, which has been corrected.
+
+ * The "--recurse-submodules" option of various subcommands did not
+   work well when run in an alternate worktree, which has been
+   corrected.
+
+ * Running "git rm" on a submodule failed unnecessarily when
+   .gitmodules is only cache-dirty, which has been corrected.
+
+ * "git rebase -i" identifies existing commits in its todo file with
+   their abbreviated object name, which could become ambigous as it
+   goes to create new commits, and has a mechanism to avoid ambiguity
+   in the main part of its execution.  A few other cases however were
+   not covered by the protection against ambiguity, which has been
+   corrected.
+
+ * The index-pack code now diagnoses a bad input packstream that
+   records the same object twice when it is used as delta base; the
+   code used to declare a software bug when encountering such an
+   input, but it is an input error.
+
+ * The code to automatically shrink the fan-out in the notes tree had
+   an off-by-one bug, which has been killed.
+
+ * "git check-ignore" did not work when the given path is explicitly
+   marked as not ignored with a negative entry in the .gitignore file.
+
+ * The merge-recursive machinery failed to refresh the cache entry for
+   a merge result in a couple of places, resulting in an unnecessary
+   merge failure, which has been fixed.
+
+ * Fix for a bug revealed by a recent change to make the protocol v2
+   the default.
+
+ * "git merge signed-tag" while lacking the public key started to say
+   "No signature", which was utterly wrong.  This regression has been
+   reverted.
+
+ * MinGW's poll() emulation has been improved.
+
+ * "git show" and others gave an object name in raw format in its
+   error output, which has been corrected to give it in hex.
+
+ * Both "git ls-remote -h" and "git grep -h" give short usage help,
+   like any other Git subcommand, but it is not unreasonable to expect
+   that the former would behave the same as "git ls-remote --head"
+   (there is no other sensible behaviour for the latter).  The
+   documentation has been updated in an attempt to clarify this.
+
+Also contains various documentation updates, code clean-ups and minor fixups.