[PATCH v2] update-hook-example: optionally allow non-fast-forward

[Dmitry Potapov <dpotapov@gmail.com>]

Sometimes it is desirable to have non-fast-forward branches in a
shared repository. A typical example of that is the 'pu' branch.
This patch extends the format of allowed-users and allow-groups
files by using the '+' sign at the beginning as the mark that
non-fast-forward pushes are permitted to the branch.

Signed-off-by: Dmitry Potapov <dpotapov@gmail.com>
---

On Wed, Jun 25, 2008 at 01:04:56PM -0700, Junio C Hamano wrote:
> 
> I'd probably write this part like so:
<snip>

Thank you for advice. I have corrected the patch.

 Documentation/howto/update-hook-example.txt |   75 ++++++++++++++++-----------
 1 files changed, 45 insertions(+), 30 deletions(-)

diff --git a/Documentation/howto/update-hook-example.txt b/Documentation/howto/update-hook-example.txt
index a8d3bae..7f430a0 100644
--- a/Documentation/howto/update-hook-example.txt
+++ b/Documentation/howto/update-hook-example.txt
@@ -65,7 +65,7 @@ function info {
 
 # Implement generic branch and tag policies.
 # - Tags should not be updated once created.
-# - Branches should only be fast-forwarded.
+# - Branches should only be fast-forwarded unless their pattern starts with '+'
 case "$1" in
   refs/tags/*)
     git rev-parse --verify -q "$1" &&
@@ -80,7 +80,7 @@ case "$1" in
       mb=$(git-merge-base "$2" "$3")
       case "$mb,$2" in
         "$2,$mb") info "Update is fast-forward" ;;
-        *)        deny >/dev/null  "This is not a fast-forward update." ;;
+        *)        noff=y; info "This is not a fast-forward update.";;
       esac
     fi
     ;;
@@ -97,19 +97,25 @@ info "The user is: '$username'"
 
 if [ -f "$allowed_users_file" ]; then
   rc=$(cat $allowed_users_file | grep -v '^#' | grep -v '^$' |
-    while read head_pattern user_patterns; do
-      matchlen=$(expr "$1" : "$head_pattern")
-      if [ "$matchlen" == "${#1}" ]; then
-        info "Found matching head pattern: '$head_pattern'"
-        for user_pattern in $user_patterns; do
-          info "Checking user: '$username' against pattern: '$user_pattern'"
-          matchlen=$(expr "$username" : "$user_pattern")
-          if [ "$matchlen" == "${#username}" ]; then
-            grant "Allowing user: '$username' with pattern: '$user_pattern'"
-          fi
-        done
-        deny "The user is not in the access list for this branch"
-      fi
+    while read heads user_patterns; do
+      #  does this rule apply to us?
+      head_pattern=${heads#+}
+      matchlen=$(expr "$1" : "${head_pattern#+}")
+      test "$matchlen" = ${#1} || continue
+
+      # if non-ff, $heads must be with the '+' prefix
+      test -n "$noff" &&
+      test "$head_pattern" = "$heads" && continue
+
+      info "Found matching head pattern: '$head_pattern'"
+      for user_pattern in $user_patterns; do
+        info "Checking user: '$username' against pattern: '$user_pattern'"
+        matchlen=$(expr "$username" : "$user_pattern")
+        if [ "$matchlen" == "${#username}" ]; then
+          grant "Allowing user: '$username' with pattern: '$user_pattern'"
+        fi
+      done
+      deny "The user is not in the access list for this branch"
     done
   )
   case "$rc" in
@@ -127,20 +133,27 @@ info "'$groups'"
 if [ -f "$allowed_groups_file" ]; then
   rc=$(cat $allowed_groups_file | grep -v '^#' | grep -v '^$' |
     while read head_pattern group_patterns; do
-      matchlen=$(expr "$1" : "$head_pattern")
-      if [ "$matchlen" == "${#1}" ]; then
-        info "Found matching head pattern: '$head_pattern'"
-        for group_pattern in $group_patterns; do
-          for groupname in $groups; do
-            info "Checking group: '$groupname' against pattern: '$group_pattern'"
-            matchlen=$(expr "$groupname" : "$group_pattern")
-            if [ "$matchlen" == "${#groupname}" ]; then
-              grant "Allowing group: '$groupname' with pattern: '$group_pattern'"
-            fi
-          done
+
+      #  does this rule apply to us?
+      head_pattern=${heads#+}
+      matchlen=$(expr "$1" : "${head_pattern#+}")
+      test "$matchlen" = ${#1} || continue
+
+      # if non-ff, $heads must be with the '+' prefix
+      test -n "$noff" &&
+      test "$head_pattern" = "$heads" && continue
+
+      info "Found matching head pattern: '$head_pattern'"
+      for group_pattern in $group_patterns; do
+        for groupname in $groups; do
+          info "Checking group: '$groupname' against pattern: '$group_pattern'"
+          matchlen=$(expr "$groupname" : "$group_pattern")
+          if [ "$matchlen" == "${#groupname}" ]; then
+            grant "Allowing group: '$groupname' with pattern: '$group_pattern'"
+          fi
         done
-        deny "None of the user's groups are in the access list for this branch"
-      fi
+      done
+      deny "None of the user's groups are in the access list for this branch"
     done
   )
   case "$rc" in
@@ -159,6 +172,7 @@ allowed-groups, to describe which heads can be pushed into by
 whom.  The format of each file would look like this:
 
         refs/heads/master	junio
+        +refs/heads/pu		junio
         refs/heads/cogito$	pasky
         refs/heads/bw/.*	linus
         refs/heads/tmp/.*	.*
@@ -166,7 +180,8 @@ whom.  The format of each file would look like this:
 
 With this, Linus can push or create "bw/penguin" or "bw/zebra"
 or "bw/panda" branches, Pasky can do only "cogito", and JC can
-do master branch and make versioned tags.  And anybody can do
-tmp/blah branches.
+do master and pu branches and make versioned tags.  And anybody
+can do tmp/blah branches. The '+' sign at the pu record means
+that JC can make non-fast-forward pushes on it.
 
 ------------
-- 
1.5.6