From bf865b6383af86f4095f9ec9c98b141be6352fc3 Mon Sep 17 00:00:00 2001
From: "Karl O. Pinc" <kop@karlpinc.com>
Date: Sun, 3 Sep 2023 14:50:01 -0500
Subject: [PATCH] Support creations and deletions

---
 lib/git_email_hook.sh | 68 ++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 61 insertions(+), 7 deletions(-)

diff --git a/lib/git_email_hook.sh b/lib/git_email_hook.sh
index 1b85ecf..8baab77 100755
--- a/lib/git_email_hook.sh
+++ b/lib/git_email_hook.sh
@@ -33,49 +33,103 @@
 # of a bare repository, the hooks/ directory) and give it the
 # name: post-receive
 #
+# Notes:
+# Turns out it's hard to find the name of the branch from which a ref
+# branched.  Instead we use awk to filter out the commits in the parent
+# branch.  (And give up on producing summary statistics for newly created
+# branches.)
+#
 # Karl O. Pinc <kop@karlpinc.com>
 
 # Emails line break at 78 chars (IIRC)
 STAT_WIDTH=77
+STANDARD_STAT_ARGS="--stat-width=${STAT_WIDTH} --compact-summary"
 
 REPO_PATH="$(git rev-parse --absolute-git-dir)"
 EMAIL_RECIPIENTS="git-push-email-recipients-${REPO_PATH}"
 
 SUBJECT="Git push report from the repository at $(hostname):${REPO_PATH}"
 
+to_branch () {
+    # Filter out all `git log` output after the first branchpoint commit
+    awk 'BEGIN {past_first = 0;
+                branch_found = 0;
+                send_output = 1; };
+         /^commit / {if (branch_found)
+                        send_output = 0 };
+         /^commit .*\(.*refs\/heads\/.+\)$/ {if (past_first)
+                                           branch_found = 1
+                                         else
+                                           past_first = 1; };
+         {if (send_output)
+            print; };' \
+      | head -n -1
+}
+
 breakline=''
 while read oval nval ref ; do
     printf "${breakline}"
 
     rev_type="$(git cat-file -t ${nval} 2>/dev/null)"
-    if expr "$oval" : '^0*$' >/dev/null ; then
+    deleted='n'
+    created='n'
+    filter='cat'
+    if expr " ${oval}" : ' 00*$' >/dev/null ; then
         # All zeros means some sort of creation operation
+        created='y'
         rev_range="${nval}"
         # (At the time of this writing diffs don't work when pushing
         # the first branch into a repo, so turn off stats in the log
         # display.)
         do_stat='n'
+        if [ $(git branch | wc -l) -eq 1 ] ; then
+            stat_args='--name-only'
+        else
+            stat_args="${STANDARD_STAT_ARGS}"
+        fi
+        filter='to_branch'
+    elif expr " ${nval}" : ' 00*$' > /dev/null ; then
+        # Zeros for a new value means deletion
+        rev_type="$(git cat-file -t ${oval} 2>/dev/null)"
+        deleted='y'
+        do_stat='n'
         stat_args='--name-only'
     else
         rev_range="${oval}..${nval}"
         do_stat='y'
-        stat_args="--stat-width=${STAT_WIDTH} --compact-summary"
+        stat_args="${STANDARD_STAT_ARGS}"
     fi
 
+    refname="$(basename ${ref})"
     if [ "${rev_type}" = 'commit' ] ; then
-        git log --decorate=full ${stat_args} "${rev_range}"
+        if [ "${deleted}" = 'y' ] ; then
+            printf 'Branch deleted: %s' "${refname}"
+        fi
+
+        git log --decorate=full ${stat_args} "${rev_range}" \
+            | ${filter}
 
         if [ "${do_stat}" = 'y' ] ; then
             printf '\n````````````````````````````````````````````````````\n'
             printf '\nSummary of changes to the branch: %s\n' \
-                   "$(basename ${ref})"
+                   "${refname}"
             git diff --stat=${STAT_WIDTH} "${rev_range}"
         else
-            printf '\n\nNo summary statistics available.\n'
+            printf '\n\n'
+            [ "${created}" = 'y' ] \
+                && printf 'New branch: %s\n' "${refname}"
+            printf 'No summary statistics available.\n'
         fi
     else
-        printf 'Information on the push of a %s:\n\n' "${rev_type}"
-        git log --decorate=full --name-only --max-count=1 ${nval}
+        printf 'Information on the push of a %s:\n' "${rev_type}"
+        if [ "${deleted}" = 'y' ] ; then
+            printf '\nDeleted: %s\n' "${refname}"
+        else
+            if [ "${created}" = 'y' ] ; then
+                printf '\nCreated: %s\n\n' "${refname}"
+            fi
+            git log --decorate=full --name-only --max-count=1 ${nval}
+        fi
     fi
 
     breakline='\n====================================================\n'
-- 
2.34.1