Re: [PATCH] scripts: Add git-resolve tool for full SHA-1 resolution

Simon Horman
2025-03-16T13:24:24Z

On Tue, Mar 11, 2025 at 12:53:36PM -0400, Sasha Levin wrote:
> Introduce git-resolve.sh, a tool that resolves short git commit IDs to their
> full SHA-1 hash. This is particularly useful for navigating references in commit
> messages and verifying Fixes tags.
>
> When faced with ambiguous commit IDs or imprecise references in messages,
> this tool can help by resolving commit hashes based on not just the ID
> itself but also the commit subject, making it more robust than standard
> git rev-parse.
>
> This is especially valuable for maintainers who need to verify Fixes tags
> or cross-reference commits. Unlike proposals to add dates to Fixes tags
> (which would break existing tooling), this script provides a way to
> disambiguate commits without changing the established tag format.
>
> The script includes several features:
> - Resolves short commit IDs to full SHA-1 hashes
> - Uses commit subjects to disambiguate between multiple potential matches
> - Supports wildcard patterns in subjects with ellipsis (...)
> - Provides a force mode to attempt resolution by subject when ID lookup fails
> - Includes comprehensive self-tests
>
> Signed-off-by: Sasha Levin <sashal@kernel.org>
> ---
> scripts/git-resolve.sh | 199 +++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 199 insertions(+)
> create mode 100755 scripts/git-resolve.sh
>
> diff --git a/scripts/git-resolve.sh b/scripts/git-resolve.sh

...

> +git_resolve_commit() {
> + local force=0
> + if [ "$1" = "--force" ]; then
> + force=1
> + shift
> + fi
> +
> + # Split input into commit ID and subject
> + local input="$*"
> + local commit_id="${input%% *}"
> + local subject=""
> +
> + # Extract subject if present (everything after the first space)
> + if [[ "$input" == *" "* ]]; then
> + subject="${input#* }"
> + # Strip the ("...") quotes if present
> + subject="${subject#*(\"}"
> + subject="${subject%\")*}"
> + fi
> +
> + # Get all possible matching commit IDs
> + local matches
> + readarray -t matches < <(git rev-parse --disambiguate="$commit_id" 2>/dev/null)
> +
> + # Return immediately if we have exactly one match
> + if [ ${#matches[@]} -eq 1 ]; then
> + echo "${matches[0]}"
> + return 0
> + fi
> +
> + # If no matches and not in force mode, return failure
> + if [ ${#matches[@]} -eq 0 ] && [ $force -eq 0 ]; then
> + return 1
> + fi
> +
> + # If we have a subject, try to find a match with that subject
> + if [ -n "$subject" ]; then
> + # Convert subject with possible ellipsis to grep pattern
> + local grep_pattern
> + grep_pattern=$(convert_to_grep_pattern "$subject")
> +
> + # In force mode with no ID matches, use git log --grep directly
> + if [ ${#matches[@]} -eq 0 ] && [ $force -eq 1 ]; then
> + # Use git log to search, but filter to ensure subject matches exactly
> + local match

I suppose it doesn't matter in practice, but it seems somewhat inconsistent
to declare match as local here...

> + match=$(git log --format="%H %s" --grep="$grep_pattern" --perl-regexp -10 | \
> + while read -r hash subject; do
> + if echo "$subject" | grep -qP "$grep_pattern"; then
> + echo "$hash"
> + break
> + fi
> + done)
> + if [ -n "$match" ]; then
> + echo "$match"
> + return 0
> + fi
> + else
> + # Normal subject matching for existing matches

... but not here.

> + for match in "${matches[@]}"; do
> + if git log -1 --format="%s" "$match" | grep -qP "$grep_pattern"; then
> + echo "$match"
> + return 0
> + fi
> + done
> + fi
> + fi
> +
> + # No match found
> + return 1
> +}

...