Count the number of commits on a Git branch

Question

I found this answer already: Number of commits on branch in git but that assumes that the branch was created from master.

How can I count the number of commits along

Answer 1

Well, the selected answer doesn't work if you forked your branch out of unspecific branch (i.e., not master or develop).

Here I offer a another way I am using in my pre-push git hooks.

# Run production build before push
echo "[INFO] run .git/hooks/pre-push"

echo "[INFO] Check if only one commit"

# file .git/hooks/pre-push
currentBranch=$(git symbolic-ref HEAD | sed -e 's,.*/\(.*\),\1,')

gitLog=$(git log --graph --abbrev-commit --decorate  --first-parent HEAD)

commitCountOfCurrentBranch=0
startCountCommit=""
baseBranch=""

while read -r line; do

    # if git log line started with something like "* commit aaface7 (origin/BRANCH_NAME)" or "commit ae4f131 (HEAD -> BRANCH_NAME)"
    # that means it's on our branch BRANCH_NAME

    matchedCommitSubstring="$( [[ $line =~ \*[[:space:]]commit[[:space:]].*\((.*)\) ]] && echo ${BASH_REMATCH[1]} )"

    if [[ ! -z ${matchedCommitSubstring} ]];then

      if [[  $line =~ $currentBranch ]];then
        startCountCommit="true"
      else
        startCountCommit=""

        if [[ -z ${baseBranch} ]];then
          baseBranch=$( [[ ${matchedCommitSubstring} =~ (.*)\, ]] && echo ${BASH_REMATCH[1]} || echo ${matchedCommitSubstring} )

        fi

      fi

    fi


    if [[ ! -z ${startCountCommit} && $line =~ ^\*[[:space:]]commit[[:space:]] ]];then
      ((commitCountOfCurrentBranch++))
    fi


done <<< "$gitLog"

if [[ -z ${baseBranch} ]];then

  baseBranch="origin/master"

else

  baseBranch=$( [[ ${baseBranch} =~ ^(.*)\, ]] && echo ${BASH_REMATCH[1]} || echo ${baseBranch} )

fi


echo "[INFO] Current commit count of the branch ${currentBranch}:  ${commitCountOfCurrentBranch}"

if [[ ${commitCountOfCurrentBranch} -gt 1 ]];then
  echo "[ERROR] Only a commit per branch is allowed. Try run 'git rebase -i ${baseBranch}'"
  exit 1
fi

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