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, 42 insertions, 7 deletions

diff --git a/third_party/git/Documentation/technical/pack-protocol.txt b/third_party/git/Documentation/technical/pack-protocol.txt
index c73e72de0e..e13a2c064d 100644
--- a/third_party/git/Documentation/technical/pack-protocol.txt
+++ b/third_party/git/Documentation/technical/pack-protocol.txt
@@ -96,7 +96,7 @@ Basically what the Git client is doing to connect to an 'upload-pack'
 process on the server side over the Git protocol is this:
 
    $ echo -e -n \
-     "0039git-upload-pack /schacon/gitbook.git\0host=example.com\0" |
+     "003agit-upload-pack /schacon/gitbook.git\0host=example.com\0" |
      nc -v example.com 9418
 
 
@@ -171,9 +171,9 @@ with a version number (if "version=1" is sent as an Extra Parameter),
 and a listing of each reference it has (all branches and tags) along
 with the object name that each reference currently points to.
 
-   $ echo -e -n "0044git-upload-pack /schacon/gitbook.git\0host=example.com\0\0version=1\0" |
+   $ echo -e -n "0045git-upload-pack /schacon/gitbook.git\0host=example.com\0\0version=1\0" |
       nc -v example.com 9418
-   000aversion 1
+   000eversion 1
    00887217a7c7e582c46cec22a130adf4b9d7d950fba0 HEAD\0multi_ack thin-pack
 		side-band side-band-64k ofs-delta shallow no-progress include-tag
    00441d3fcd5ced445d1abc402225c0b8a1299641f497 refs/heads/integration
@@ -503,8 +503,8 @@ The reference discovery phase is done nearly the same way as it is in the
 fetching protocol. Each reference obj-id and name on the server is sent
 in packet-line format to the client, followed by a flush-pkt.  The only
 real difference is that the capability listing is different - the only
-possible values are 'report-status', 'delete-refs', 'ofs-delta' and
-'push-options'.
+possible values are 'report-status', 'report-status-v2', 'delete-refs',
+'ofs-delta', 'atomic' and 'push-options'.
 
 Reference Update Request and Packfile Transfer
 ----------------------------------------------
@@ -625,7 +625,7 @@ Report Status
 -------------
 
 After receiving the pack data from the sender, the receiver sends a
-report if 'report-status' capability is in effect.
+report if 'report-status' or 'report-status-v2' capability is in effect.
 It is a short listing of what happened in that update.  It will first
 list the status of the packfile unpacking as either 'unpack ok' or
 'unpack [error]'.  Then it will list the status for each of the references
@@ -644,7 +644,42 @@ update was successful, or 'ng [refname] [error]' if the update was not.
   command-ok        = PKT-LINE("ok" SP refname)
   command-fail      = PKT-LINE("ng" SP refname SP error-msg)
 
-  error-msg         = 1*(OCTECT) ; where not "ok"
+  error-msg         = 1*(OCTET) ; where not "ok"
+----
+
+The 'report-status-v2' capability extends the protocol by adding new option
+lines in order to support reporting of reference rewritten by the
+'proc-receive' hook.  The 'proc-receive' hook may handle a command for a
+pseudo-reference which may create or update one or more references, and each
+reference may have different name, different new-oid, and different old-oid.
+
+----
+  report-status-v2  = unpack-status
+		      1*(command-status-v2)
+		      flush-pkt
+
+  unpack-status     = PKT-LINE("unpack" SP unpack-result)
+  unpack-result     = "ok" / error-msg
+
+  command-status-v2 = command-ok-v2 / command-fail
+  command-ok-v2     = command-ok
+		      *option-line
+
+  command-ok        = PKT-LINE("ok" SP refname)
+  command-fail      = PKT-LINE("ng" SP refname SP error-msg)
+
+  error-msg         = 1*(OCTET) ; where not "ok"
+
+  option-line       = *1(option-refname)
+		      *1(option-old-oid)
+		      *1(option-new-oid)
+		      *1(option-forced-update)
+
+  option-refname    = PKT-LINE("option" SP "refname" SP refname)
+  option-old-oid    = PKT-LINE("option" SP "old-oid" SP obj-id)
+  option-new-oid    = PKT-LINE("option" SP "new-oid" SP obj-id)
+  option-force      = PKT-LINE("option" SP "forced-update")
+
 ----
 
 Updates can be unsuccessful for a number of reasons.  The reference can have