4 files changed, 207 insertions, 5 deletions
diff --git a/Documentation/technical/api-hashmap.txt b/Documentation/technical/api-hashmap.txt
index ad7a5bddd2..28f5a8b715 100644
--- a/Documentation/technical/api-hashmap.txt
+++ b/Documentation/technical/api-hashmap.txt
@@ -104,6 +104,11 @@ If `free_entries` is true, each hashmap_entry in the map is freed as well
 `entry` points to the entry to initialize.
 +
 `hash` is the hash code of the entry.
++
+The hashmap_entry structure does not hold references to external resources,
+and it is safe to just discard it once you are done with it (i.e. if
+your structure was allocated with xmalloc(), you can just free(3) it,
+and if it is on stack, you can just let it go out of scope).
 
 `void *hashmap_get(const struct hashmap *map, const void *key, const void *keydata)`::
 
diff --git a/Documentation/technical/pack-protocol.txt b/Documentation/technical/pack-protocol.txt
index 8b36343802..736f3894a8 100644
--- a/Documentation/technical/pack-protocol.txt
+++ b/Documentation/technical/pack-protocol.txt
@@ -307,7 +307,7 @@ In multi_ack mode:
     ready to make a packfile, it will blindly ACK all 'have' obj-ids
     back to the client.
 
-  * the server will then send a 'NACK' and then wait for another response
+  * the server will then send a 'NAK' and then wait for another response
     from the client - either a 'done' or another list of 'have' lines.
 
 In multi_ack_detailed mode:
@@ -454,7 +454,8 @@ 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' and 'ofs-delta'.
+possible values are 'report-status', 'delete-refs', 'ofs-delta' and
+'push-options'.
 
 Reference Update Request and Packfile Transfer
 ----------------------------------------------
@@ -465,9 +466,10 @@ that it wants to update, it sends a line listing the obj-id currently on
 the server, the obj-id the client would like to update it to and the name
 of the reference.
 
-This list is followed by a flush-pkt and then the packfile that should
-contain all the objects that the server will need to complete the new
-references.
+This list is followed by a flush-pkt. Then the push options are transmitted
+one per packet followed by another flush-pkt. After that the packfile that
+should contain all the objects that the server will need to complete the new
+references will be sent.
 
 ----
   update-request    =  *shallow ( command-list | push-cert ) [packfile]
diff --git a/Documentation/technical/protocol-capabilities.txt b/Documentation/technical/protocol-capabilities.txt
index eaab6b4ac7..4c28d3a8ae 100644
--- a/Documentation/technical/protocol-capabilities.txt
+++ b/Documentation/technical/protocol-capabilities.txt
@@ -253,6 +253,15 @@ atomic pushes. If the pushing client requests this capability, the server
 will update the refs in one atomic transaction. Either all refs are
 updated or none.
 
+push-options
+------------
+
+If the server sends the 'push-options' capability it is able to accept
+push options after the update commands have been sent, but before the
+packfile is streamed. If the pushing client requests this capability,
+the server will pass the options to the pre- and post- receive hooks
+that process this push request.
+
 allow-tip-sha1-in-want
 ----------------------
 
diff --git a/Documentation/technical/signature-format.txt b/Documentation/technical/signature-format.txt
new file mode 100644
index 0000000000..2c9406a56a
--- /dev/null
+++ b/Documentation/technical/signature-format.txt
@@ -0,0 +1,186 @@
+Git signature format
+====================
+
+== Overview
+
+Git uses cryptographic signatures in various places, currently objects (tags,
+commits, mergetags) and transactions (pushes). In every case, the command which
+is about to create an object or transaction determines a payload from that,
+calls gpg to obtain a detached signature for the payload (`gpg -bsa`) and
+embeds the signature into the object or transaction.
+
+Signatures always begin with `-----BEGIN PGP SIGNATURE-----`
+and end with `-----END PGP SIGNATURE-----`, unless gpg is told to
+produce RFC1991 signatures which use `MESSAGE` instead of `SIGNATURE`.
+
+The signed payload and the way the signature is embedded depends
+on the type of the object resp. transaction.
+
+== Tag signatures
+
+- created by: `git tag -s`
+- payload: annotated tag object
+- embedding: append the signature to the unsigned tag object
+- example: tag `signedtag` with subject `signed tag`
+
+----
+object 04b871796dc0420f8e7561a895b52484b701d51a
+type commit
+tag signedtag
+tagger C O Mitter <committer@example.com> 1465981006 +0000
+
+signed tag
+
+signed tag message body
+-----BEGIN PGP SIGNATURE-----
+Version: GnuPG v1
+
+iQEcBAABAgAGBQJXYRhOAAoJEGEJLoW3InGJklkIAIcnhL7RwEb/+QeX9enkXhxn
+rxfdqrvWd1K80sl2TOt8Bg/NYwrUBw/RWJ+sg/hhHp4WtvE1HDGHlkEz3y11Lkuh
+8tSxS3qKTxXUGozyPGuE90sJfExhZlW4knIQ1wt/yWqM+33E9pN4hzPqLwyrdods
+q8FWEqPPUbSJXoMbRPw04S5jrLtZSsUWbRYjmJCHzlhSfFWW4eFd37uquIaLUBS0
+rkC3Jrx7420jkIpgFcTI2s60uhSQLzgcCwdA2ukSYIRnjg/zDkj8+3h/GaROJ72x
+lZyI6HWixKJkWw8lE9aAOD9TmTW9sFJwcVAzmAuFX2kUreDUKMZduGcoRYGpD7E=
+=jpXa
+-----END PGP SIGNATURE-----
+----
+
+- verify with: `git verify-tag [-v]` or `git tag -v`
+
+----
+gpg: Signature made Wed Jun 15 10:56:46 2016 CEST using RSA key ID B7227189
+gpg: Good signature from "Eris Discordia <discord@example.net>"
+gpg: WARNING: This key is not certified with a trusted signature!
+gpg:          There is no indication that the signature belongs to the owner.
+Primary key fingerprint: D4BE 2231 1AD3 131E 5EDA  29A4 6109 2E85 B722 7189
+object 04b871796dc0420f8e7561a895b52484b701d51a
+type commit
+tag signedtag
+tagger C O Mitter <committer@example.com> 1465981006 +0000
+
+signed tag
+
+signed tag message body
+----
+
+== Commit signatures
+
+- created by: `git commit -S`
+- payload: commit object
+- embedding: header entry `gpgsig`
+  (content is preceded by a space)
+- example: commit with subject `signed commit`
+
+----
+tree eebfed94e75e7760540d1485c740902590a00332
+parent 04b871796dc0420f8e7561a895b52484b701d51a
+author A U Thor <author@example.com> 1465981137 +0000
+committer C O Mitter <committer@example.com> 1465981137 +0000
+gpgsig -----BEGIN PGP SIGNATURE-----
+ Version: GnuPG v1
+
+ iQEcBAABAgAGBQJXYRjRAAoJEGEJLoW3InGJ3IwIAIY4SA6GxY3BjL60YyvsJPh/
+ HRCJwH+w7wt3Yc/9/bW2F+gF72kdHOOs2jfv+OZhq0q4OAN6fvVSczISY/82LpS7
+ DVdMQj2/YcHDT4xrDNBnXnviDO9G7am/9OE77kEbXrp7QPxvhjkicHNwy2rEflAA
+ zn075rtEERDHr8nRYiDh8eVrefSO7D+bdQ7gv+7GsYMsd2auJWi1dHOSfTr9HIF4
+ HJhWXT9d2f8W+diRYXGh4X0wYiGg6na/soXc+vdtDYBzIxanRqjg8jCAeo1eOTk1
+ EdTwhcTZlI0x5pvJ3H0+4hA2jtldVtmPM4OTB0cTrEWBad7XV6YgiyuII73Ve3I=
+ =jKHM
+ -----END PGP SIGNATURE-----
+
+signed commit
+
+signed commit message body
+----
+
+- verify with: `git verify-commit [-v]` (or `git show --show-signature`)
+
+----
+gpg: Signature made Wed Jun 15 10:58:57 2016 CEST using RSA key ID B7227189
+gpg: Good signature from "Eris Discordia <discord@example.net>"
+gpg: WARNING: This key is not certified with a trusted signature!
+gpg:          There is no indication that the signature belongs to the owner.
+Primary key fingerprint: D4BE 2231 1AD3 131E 5EDA  29A4 6109 2E85 B722 7189
+tree eebfed94e75e7760540d1485c740902590a00332
+parent 04b871796dc0420f8e7561a895b52484b701d51a
+author A U Thor <author@example.com> 1465981137 +0000
+committer C O Mitter <committer@example.com> 1465981137 +0000
+
+signed commit
+
+signed commit message body
+----
+
+== Mergetag signatures
+
+- created by: `git merge` on signed tag
+- payload/embedding: the whole signed tag object is embedded into
+  the (merge) commit object as header entry `mergetag`
+- example: merge of the signed tag `signedtag` as above
+
+----
+tree c7b1cff039a93f3600a1d18b82d26688668c7dea
+parent c33429be94b5f2d3ee9b0adad223f877f174b05d
+parent 04b871796dc0420f8e7561a895b52484b701d51a
+author A U Thor <author@example.com> 1465982009 +0000
+committer C O Mitter <committer@example.com> 1465982009 +0000
+mergetag object 04b871796dc0420f8e7561a895b52484b701d51a
+ type commit
+ tag signedtag
+ tagger C O Mitter <committer@example.com> 1465981006 +0000
+
+ signed tag
+
+ signed tag message body
+ -----BEGIN PGP SIGNATURE-----
+ Version: GnuPG v1
+
+ iQEcBAABAgAGBQJXYRhOAAoJEGEJLoW3InGJklkIAIcnhL7RwEb/+QeX9enkXhxn
+ rxfdqrvWd1K80sl2TOt8Bg/NYwrUBw/RWJ+sg/hhHp4WtvE1HDGHlkEz3y11Lkuh
+ 8tSxS3qKTxXUGozyPGuE90sJfExhZlW4knIQ1wt/yWqM+33E9pN4hzPqLwyrdods
+ q8FWEqPPUbSJXoMbRPw04S5jrLtZSsUWbRYjmJCHzlhSfFWW4eFd37uquIaLUBS0
+ rkC3Jrx7420jkIpgFcTI2s60uhSQLzgcCwdA2ukSYIRnjg/zDkj8+3h/GaROJ72x
+ lZyI6HWixKJkWw8lE9aAOD9TmTW9sFJwcVAzmAuFX2kUreDUKMZduGcoRYGpD7E=
+ =jpXa
+ -----END PGP SIGNATURE-----
+
+Merge tag 'signedtag' into downstream
+
+signed tag
+
+signed tag message body
+
+# gpg: Signature made Wed Jun 15 08:56:46 2016 UTC using RSA key ID B7227189
+# gpg: Good signature from "Eris Discordia <discord@example.net>"
+# gpg: WARNING: This key is not certified with a trusted signature!
+# gpg:          There is no indication that the signature belongs to the owner.
+# Primary key fingerprint: D4BE 2231 1AD3 131E 5EDA  29A4 6109 2E85 B722 7189
+----
+
+- verify with: verification is embedded in merge commit message by default,
+  alternatively with `git show --show-signature`:
+
+----
+commit 9863f0c76ff78712b6800e199a46aa56afbcbd49
+merged tag 'signedtag'
+gpg: Signature made Wed Jun 15 10:56:46 2016 CEST using RSA key ID B7227189
+gpg: Good signature from "Eris Discordia <discord@example.net>"
+gpg: WARNING: This key is not certified with a trusted signature!
+gpg:          There is no indication that the signature belongs to the owner.
+Primary key fingerprint: D4BE 2231 1AD3 131E 5EDA  29A4 6109 2E85 B722 7189
+Merge: c33429b 04b8717
+Author: A U Thor <author@example.com>
+Date:   Wed Jun 15 09:13:29 2016 +0000
+
+    Merge tag 'signedtag' into downstream
+
+    signed tag
+
+    signed tag message body
+
+    # gpg: Signature made Wed Jun 15 08:56:46 2016 UTC using RSA key ID B7227189
+    # gpg: Good signature from "Eris Discordia <discord@example.net>"
+    # gpg: WARNING: This key is not certified with a trusted signature!
+    # gpg:          There is no indication that the signature belongs to the owner.
+    # Primary key fingerprint: D4BE 2231 1AD3 131E 5EDA  29A4 6109 2E85 B722 7189
+----