Automatically bump the semantic version tag if there are changes since the last (with discrimination between major, minor, patch bumps from comments)

ado_bump.sh

# https://gist.github.com/NickLarsenNZ/ee907e05429a02fb6f2bcc73e7c34733
set -euo pipefail

COMMIT_MESSAGES=""
LAST_TAG=$(git describe --abbrev=0 --tags 2>/dev/null)

if [ -z "$LAST_TAG" ]; then
    >&2 echo "No tags previously defined"
    LAST_TAG="0.0.1"
    # Get commit logs for all time
    COMMIT_MESSAGES=$(git log --pretty=format:'%s' --abbrev-commit)
else
    # Ensure semver
    echo -n "Validating last version: "
    grep --color -E "[0-9]+\.[0-9]+\.[0-9]+[-+]?.*" <(echo $LAST_TAG)

    # Get commit logs between now and the last semver
    COMMIT_MESSAGES=$(git log --pretty=format:'%s' --abbrev-commit HEAD...${LAST_TAG})

    # If the commit log is empty, then we don't need to bump
    if [ -z "$COMMIT_MESSAGES" ]; then
        >&2 echo "No change since the last tag"
        echo $LAST_TAG
        exit 0
    fi
fi

# Check if the commit logs contain major/minor changes
echo "${COMMIT_MESSAGES}" | grep -i '\[major\]' &> /dev/null
IS_MAJOR=$?
echo "${COMMIT_MESSAGES}" | grep -i '\[minor\]' &> /dev/null
IS_MINOR=$?

MAJOR=$(echo $LAST_TAG | cut -d. -f1 | grep -oE "^[0-9]+\$")
MINOR=$(echo $LAST_TAG | cut -d. -f2 | grep -oE "^[0-9]+\$")
PATCH=$(echo $LAST_TAG | cut -d. -f3 | grep -oE "^[0-9]+")

if [ $IS_MAJOR == 0 ]; then
  NEW_TAG=$(($MAJOR+1)).0.0
elif [ $IS_MINOR == 0 ]; then
  NEW_TAG=$MAJOR.$(($MINOR+1)).0
else
  NEW_TAG=$MAJOR.$MINOR.$(($PATCH+1))
fi

git tag $NEW_TAG
git push --tags

echo "##vso[task.setvariable variable=NEW_TAG;isOutput=true]$NEW_TAG"

bump_semver.sh

#!/usr/bin/env bash

COMMIT_MESSAGES=""
#PREVIOUS_SEMVER
#SEMVER
BUMP="patch"

PREVIOUS_SEMVER=$(git describe --abbrev=0 --tags 2>/dev/null)
if [ -z "$PREVIOUS_SEMVER" ]; then
    >&2 echo "No tags previously defined"
    PREVIOUS_SEMVER="0.0.1"
    # Get commit logs for all time
    COMMIT_MESSAGES=$(git log --pretty=format:'%s' --abbrev-commit)
else
    # Get commit logs between now and the last semver
    COMMIT_MESSAGES=$(git log --pretty=format:'%s' --abbrev-commit HEAD...${PREVIOUS_SEMVER})

    # If the commit log is empty, then we don't need to bump
    if [ -z "$COMMIT_MESSAGES" ]; then
        >&2 echo "No change since the last tag"
        echo $PREVIOUS_SEMVER
    exit 0
fi
fi

# Check if the commit logs contain major/minor changes
echo "${COMMIT_MESSAGE}" | grep -i '\[major\]' &> /dev/null
IS_MAJOR=$?
echo "${COMMIT_MESSAGE}" | grep -i '\[minor\]' &> /dev/null
IS_MINOR=$?

if [ $IS_MAJOR == 0 ]; then
    BUMP = 'major'
elif [ $IS_MINOR == 0 ]; then
    BUMP = 'minor'
fi

# Do the needful
SEMVER=$(>&2 git semver ${BUMP}) || exit 1

# Push the tags upstream
>&2 git push --tags || exit 2

# Print the new semver to stdout
echo -n $SEMVER

Usage:

curl https://gist.githubusercontent.com/NickLarsenNZ/ee907e05429a02fb6f2bcc73e7c34733/raw/48565868371b9428d582fee1db37e254b59bfc32/bump_semver.sh | bash