CHG: Correcting handling of git commit and changes when fetch has not…

… been used

.gitignore

@@ -74,4 +74,4 @@ test/NightlyRun/*.tar.gz
 
 # Custom build files #
 #=====================
-.issm
+.PREV_COMMIT

jenkins/jenkins.sh

@@ -58,17 +58,24 @@ fi
 echo "======================================================";
 echo " Determining installation type "
 echo "======================================================";
-if [ -a ${ISSM_DIR}/.issm ]; then
- # Get list of changed files
- #
- CHANGES=$(git diff --name-only ORIG_HEAD HEAD)
+if [ -f ${ISSM_DIR}/.PREV_COMMIT ]; then
+ # Fetch main branch from remote origin (this does not affect local files 
+ # like `git pull` would)
+ git fetch --quiet origin main
+
+ # Retrieve previous commit SHA
+ PREV_COMMIT=$(cat ${ISSM_DIR}/.PREV_COMMIT)
 
- # Print list of changed files
- echo " "
- echo "List of changed files"
- echo "---------------------"
- echo "${CHANGES}"
- echo " "
+ # Get list of changed files
+ CHANGES=$(git diff --name-only ${PREV_COMMIT} FETCH_HEAD)
+
+ if [ ! "${CHANGES}" == "" ]; then
+ # Print list of changed files
+ echo " "
+ echo "List of changed files"
+ echo "---------------------"
+ echo "${CHANGES}"
+ fi
 
  # If the contents of the externalpackages directory were modified in any
  # way, check for changed external packages
@@ -102,10 +109,8 @@ if [ -a ${ISSM_DIR}/.issm ]; then
  ISSM_COMPILATION="no"
  fi
 else
- # Write out hidden file so we know next time that this script it run, it is 
- # not on a fresh copy of the repo (this is really only useful when running 
- # this script manually, i.e. *not* on Jenkins)
- touch ${ISSM_DIR}/.issm
+ # Write out hidden file containing this commit's SHA
+ git rev-parse HEAD > ${ISSM_DIR}/.PREV_COMMIT
 
  echo "Fresh copy of repository; building everything"
  echo "-- checking for changed externalpackages... yes"