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

[Simon Horman <horms@kernel.org>]

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
> +}

...