first version of git-drop-changeid

git-drop-changeid

@@ -0,0 +1,56 @@
+#!/bin/bash
+# This script is meant to be run as a GIT_SEQUENCE_EDITOR 
+# when running `git rebase -i`. The idea being that it will
+# cross-reference commit logs and history with the target branch and 
+# drop any changes, squashed or otherwise, that exist on that branch
+
+FILE=${1}
+
+# Find the branch we're rebasing onto
+
+ONTO=$(awk '/^# Rebase/{ print $5 }' ${FILE})
+
+# Create tempfile to rewrite the todo list
+random=$( (whoami ; hostname ; date; cat $1) | git hash-object --stdin)
+dest="$1.tmp.${random}"
+
+trap 'rm -f "${dest}"' EXIT
+
+# For each commit...
+while read -r line; do
+    if [[ "$line" =~ ^#.* ]]; then
+      echo $line >> ${dest}
+      continue
+    fi
+    commit=$(echo -n $line | awk '{ print $2 }') 
+    if [ -z "${commit}" ]; then
+      continue
+    fi
+    # ...see if there's a Change-Id in it....
+    changeid=$(git log --format=%B -n 1 ${commit} | awk '/Change-Id/{ print $2 }')
+    if [ -n "${changeid}" ]; then
+      # ...and match it against the history of the target branch
+      gitlog=$(git log --grep "${changeid}" ${ONTO})
+      if [ -n "${gitlog}" ] ; then
+        echo $line "# Has Change-Id ${changeid}" | sed 's/pick/drop/g' >> ${dest}
+        continue
+      fi
+    fi
+    echo $line >> ${dest}
+done < ${FILE}
+
+
+# Apply the changes from the tempfile
+
+if ! mv "${dest}" "$1" ; then
+  echo "cannot mv ${dest} to $1"
+  exit 1
+fi
+
+# Proceed with the editor as per usual
+
+REAL_EDITOR="$(git var GIT_EDITOR)"
+
+if [ -n "$REAL_EDITOR" ]; then
+  $REAL_EDITOR "$@"
+fi