git-log-json.sh

#!/bin/bash
# attempting to be the most robust solution for outputting git log as JSON,
# using only `git` and the standard shell functions, without requiring
# additional software.

# - uses traditional JSON camelCase
# - includes every major field that git log can output, including the body
# - proper sections for author, committer, and signature
# - multiple date formats (one for reading, ISO for parsing)
# - should properly handle (most? all?) body values, even those that contain
#   quotation marks and escaped characters
# - outputs as minimized JSON, can be piped to `jq` for pretty printing
# - can run against the current directory as `git-log-json` or against a file
#   or folder with `git-log-json foo`
# - easily piped into `jq`, e.g. this will get all the commit subjects:
#   $ git-log-json foo | jq -r '.[] | .subject'

# credit to @nsisodiya, @varemenos, @overengineer, and others for the
# original working code:
# https://gist.github.com/varemenos/e95c2e098e657c7688fd

git_log_json() {
    IFS='' read -r -d '' FORMAT << 'EOF'
    {
        ^^^^author^^^^: { ^^^^name^^^^: ^^^^%aN^^^^,
        ^^^^email^^^^: ^^^^%aE^^^^,
        ^^^^date^^^^: ^^^^%aD^^^^,
        ^^^^dateISO8601^^^^: ^^^^%aI^^^^},
        ^^^^body^^^^: ^^^^%b^^^^,
        ^^^^commitHash^^^^: ^^^^%H^^^^,
        ^^^^commitHashAbbreviated^^^^: ^^^^%h^^^^,
        ^^^^committer^^^^: {
        ^^^^name^^^^: ^^^^%cN^^^^,
        ^^^^email^^^^: ^^^^%cE^^^^,
        ^^^^date^^^^: ^^^^%cD^^^^,
        ^^^^dateISO8601^^^^: ^^^^%cI^^^^},
        ^^^^encoding^^^^: ^^^^%e^^^^,
        ^^^^notes^^^^: ^^^^%N^^^^,
        ^^^^parent^^^^: ^^^^%P^^^^,
        ^^^^parentAbbreviated^^^^: ^^^^%p^^^^,
        ^^^^refs^^^^: ^^^^%D^^^^,
        ^^^^signature^^^^: {
        ^^^^key^^^^: ^^^^%GK^^^^,
        ^^^^signer^^^^: ^^^^%GS^^^^,
        ^^^^verificationFlag^^^^: ^^^^%G?^^^^},
        ^^^^subject^^^^: ^^^^%s^^^^,
        ^^^^subjectSanitized^^^^: ^^^^%f^^^^,
        ^^^^tree^^^^: ^^^^%T^^^^,
        ^^^^treeAbbreviated^^^^: ^^^^%t^^^^
    },
EOF
    FORMAT=$(echo "$FORMAT"|tr -d '\r\n ')

    git log --pretty=format:"$FORMAT" "$1" | \
        sed -e ':a' -e 'N' -e '$!ba' -e s'/\^^^^},\n{\^^^^/^^^^},{^^^^/g' \
        -e 's/\\/\\\\/g' -e 's/"/\\"/g' -e 's/\^^^^/"/g' -e '$ s/,$//' | \
        sed -e ':a' -e 'N' -e '$!ba' -e 's/\r//g' -e 's/\n/\\n/g' -e 's/\t/\\t/g' | \
        awk 'BEGIN { ORS=""; printf("[") } { print($0) } END { printf("]\n") }'
    }