contrib: add git-stats.sh

git shortlog -sn is nice but it does not display the number of changed
files and the amount of changed lines.

  $ git shortlog -sn 0.12.0..
      46  Tim Culverhouse
      28  Robin Jarry
      14  Koni Marti
       9  Moritz Poldrack
       2  Ben Cohen
       2  Bence Ferdinandy
       2  Julian Pidancet
       2  inwit
       1  Jason Cox
       1  Jason Stewart
       1  John Gebbie
       1  Tobias Wölfel
       1  kt programs

Add a simple bash script that adds extra information:

  $ ./contrib/git-stats.sh 0.12.0..
  Author            Commits  Changed Files  Insertions  Deletions
  Tim Culverhouse        46            134        +973      -1090
  Robin Jarry            28             70        +671       -358
  Koni Marti             14             47        +437       -205
  Moritz Poldrack         9             18        +178        -44
  Ben Cohen               2              2         +16         -2
  Bence Ferdinandy        2              6        +104         +0
  Julian Pidancet         2              9        +149         -2
  inwit                   2              3         +11         -1
  Jason Cox               1              7        +106         -6
  Jason Stewart           1              1          +4         -2
  John Gebbie             1              3        +118         -1
  Tobias Wölfel           1              3          +3         -3
  kt programs             1              3         +37         -6

Use the script to generate the release tag and email.

Signed-off-by: Robin Jarry <robin@jarry.cc>
Acked-on-irc-by: Tim Culverhouse <tim@timculverhouse.com>

contrib/git-stats.sh

@@ -0,0 +1,23 @@
+#!/bin/bash
+
+set -e
+set -o pipefail
+
+columns="Author,Commits,Changed Files,Insertions,Deletions"
+
+git shortlog -sn "$@" |
+while read -r commits author; do
+	git log --author="$author" --pretty=tformat: --numstat "$@" | {
+		adds=0
+		subs=0
+		files=0
+		while read -r a s f; do
+			adds=$((adds + a))
+			subs=$((subs + s))
+			files=$((files + 1))
+		done
+		printf '%s;%d;%d;%+d;%+d;\n' \
+			"$author" "$commits" "$files" "$adds" "-$subs"
+	}
+done |
+column -t -s ';' -N "$columns" -R "${columns#*,}"

contrib/release.sh

@@ -24,8 +24,8 @@ git -c core.commentchar='%' tag --edit --sign \
 	-m "Release $next_tag highlights:" \
 	-m "$changes" \
 	-m "Thanks to all contributors!" \
-	-m "~\$ git shortlog -sn $prev_tag..$next_tag
+	-m "~\$ contrib/git-stats.sh $prev_tag..$next_tag
-$(git shortlog -sn $prev_tag..)" \
+$(contrib/git-stats.sh $prev_tag..)" \
 	"$next_tag"
 
 echo "======= Pushing to remote..."