tools/check_commit_msg.sh - third_party/ffmpeg - Git at Google

 #!/bin/sh
 #
 # Validate commit messages against FFmpeg conventions.
 #
 # Based on lint_commit_msg.py from mpv (LGPL).
 # Original authors: Kacper Michajłow, Timo Rothenpieler
 #
 # This file is part of FFmpeg.
 #
 # FFmpeg is free software; you can redistribute it and/or modify
 # it under the terms of the GNU Lesser General Public License as published by
 # the Free Software Foundation; either version 2.1 of the License, or
 # (at your option) any later version.
 #
 # FFmpeg is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 # GNU Lesser General Public License for more details.
 #
 # You should have received a copy of the GNU Lesser General Public License
 # along with FFmpeg; if not, write to the Free Software Foundation, Inc.,
 # 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 #
 # Exit code 0 = all pass, non-zero = errors found.
 #
 # Usage:
 #   Single message from stdin:
 #     git log -1 --format="%B" <commit> | sh tools/check_commit_msg.sh
 #
 #   Single message from file (pre-commit commit-msg hook):
 #     sh tools/check_commit_msg.sh .git/COMMIT_EDITMSG
 #
 #   Multiple commits via revision range:
 #     sh tools/check_commit_msg.sh HEAD~5..HEAD
 #     sh tools/check_commit_msg.sh origin/master..my-branch
 #     sh tools/check_commit_msg.sh -10          # last 10 commits
 #
 # Examples:
 #   echo "avcodec/vvc: fix intra prediction" | sh tools/check_commit_msg.sh
 #   # => commit message OK
 #
 #   echo "fix bug" | sh tools/check_commit_msg.sh
 #   # => ERROR: subject does not match 'component: description' pattern: fix bug
 #
 # Checks (errors block, warnings only print):
 #   - Subject matches "component[/module]: description" pattern   (error)
 #   - No conventional-commits style (feat:/fix:/chore: etc.)      (error)
 #   - Blank line between subject and body (if body exists)        (error)
 #   - No duplicate Signed-off-by from same person                 (error)
 #   - No multiple subject-like lines (2+) in body (squash-mess)   (error)
 #   - Subject line <= 120 characters                              (warning)
 #   - No trailing whitespace on subject line                      (warning)
 #   - Subject does not end with a period                          (warning)
 #   - Prefix does not contain file extension (.c, .h, etc.)       (warning)

 RED='\033[1;31m'
 YEL='\033[1;33m'
 RST='\033[0m'

 # --- Single-message validation (operates on a temp file) ---

 check_message() {
     msgfile=$1
     err=0
     warn_count=0

     error() {
         printf "${RED}ERROR:${RST} %s\n" "$1" >&2
         err=1
     }

     warning() {
         printf "${YEL}WARNING:${RST} %s\n" "$1" >&2
         warn_count=$((warn_count + 1))
     }

     # Check for empty message
     if ! grep -q '[^[:space:]]' "$msgfile"; then
         error "commit message is empty"
         return $err
     fi

     # Split into subject (first line) and the rest
     subject=$(head -n 1 "$msgfile")

     # --- Subject checks ---

     # Trailing whitespace on subject (second pattern is a literal tab)
     case "$subject" in
         *" "|*"	")
             warning "trailing whitespace on subject line"
             ;;
     esac

     # Subject format: component/module: description
     # Allow nested paths like avcodec/vvc/inter: or single component like doc:
     # Also allow "Merge", "Revert" and "Reapply" subjects used by forges
     # Patterns supported:
     #   component: desc                           (avcodec/vvc: fix)
     #   component modifier: desc                  (avcodec/vvc decode: fix)
     #   component, component: desc                (avformat/a, avcodec/b: fix)
     #   .component: desc                          (.forgejo/CODEOWNERS: add)
     #   {component}: desc                         ({lib{a,b}/x86/,}Makefile: fix)
     # COMP: a component token starting with a letter, at least 2 characters.
     COMP='[a-zA-Z][]a-zA-Z0-9_./{},*?|()[-]+'
     case "$subject" in
         Merge\ *|Revert\ *|Reapply\ *)
             # Merge, revert and reapply commits get a pass on format checks
             ;;
         *)
             # Require a non-empty description after ": " so that bare
             # "component:" or "component: " (no text) are rejected.
             if ! printf '%s\n' "$subject" | grep -qE "^[{.]?${COMP}(, *${COMP})*( +[a-zA-Z0-9_]+)*: [^[:space:]]"; then
                 error "subject does not match 'component: description' pattern: $subject"
             fi

             # Do not use conventional-commits style (feat:/fix:/chore:/refactor:)
             if printf '%s\n' "$subject" | grep -qEi '^(feat|fix|chore|refactor)[!:(]'; then
                 error "do not use conventional-commits style (feat:/fix:/chore:/refactor:)"
             fi

             # Prefix should not include file extension
             prefix=$(printf '%s\n' "$subject" | sed -n 's/: .*//p')
             if printf '%s\n' "$prefix" | grep -qE '[a-z0-9]\.(c|h|m|texi)$'; then
                 warning "prefix should not include file extension: $prefix"
             fi
             ;;
     esac

     # Subject should not end with a period
     case "$subject" in
         *.)
             warning "subject should not end with a period"
             ;;
     esac

     # Subject length
     subj_len=${#subject}
     if [ "$subj_len" -gt 120 ]; then
         warning "subject is $subj_len characters (> 120)"
     fi

     # --- Blank line between subject and body ---
     # Use sed to check line 2 directly; works regardless of trailing newline.
     second_line=$(sed -n '2p' "$msgfile")
     rest=$(sed -n '2,$p' "$msgfile")
     if [ -n "$rest" ]; then
         if [ -n "$second_line" ]; then
             error "missing blank line between subject and body"
         fi

         # Body is everything after the blank separator line
         body=$(tail -n +3 "$msgfile")
     else
         body=""
     fi

     # --- Squash-mess detection ---

     if [ -n "$body" ]; then
         # Multiple Signed-off-by from the same person
         sob_dups=$(printf '%s\n' "$body" | grep -i '^Signed-off-by:' | sort | uniq -d)
         if [ -n "$sob_dups" ]; then
             error "duplicate Signed-off-by: $(printf '%s\n' "$sob_dups" | head -n 1)"
         fi

         # Heuristic squash detection: count body lines that look like
         # additional commit subjects of the form "component/module: text".
         # Intentionally restricted to prefixes that contain '/' so that
         # prose definitions (e.g. "maximum: No restriction") and data
         # labels are not flagged as subjects; this trades recall for
         # precision and will not catch squash bodies made entirely of
         # single-component subjects like "doc: ..." or "configure: ...".
         # Match any non-space after ": " so lowercase subjects are counted too.
         # Exclude known trailer tags.
         subj_like_count=$(printf '%s\n' "$body" \
             | grep -E '^[a-zA-Z][a-zA-Z0-9_./-]*/[a-zA-Z0-9_./-]+: [^[:space:]]' \
             | grep -ivcE '^(Signed-off-by|Reviewed-by|Acked-by|Tested-by|CC|Reported-by|Co-authored-by|Link|Fixes|Note|Suggested-by|Bug):')
         if [ "$subj_like_count" -ge 2 ]; then
             error "body contains $subj_like_count subject-like lines (squash-mess?)"
         fi
     fi

     if [ $err -eq 0 ] && [ $warn_count -eq 0 ]; then
         printf "commit message OK\n"
     fi

     return $err
 }

 # --- Main ---

 if [ $# -eq 0 ]; then
     # No argument: read a single message from stdin
     tmpfile=$(mktemp)
     trap 'rm -f "$tmpfile"' EXIT
     cat > "$tmpfile"
     check_message "$tmpfile"
     exit $?
 elif [ $# -eq 1 ] && [ -f "$1" ]; then
     # Single argument is an existing file: treat as commit message file
     # (used by pre-commit commit-msg hook passing .git/COMMIT_EDITMSG)
     check_message "$1"
     exit $?
 else
     # Argument(s) provided: treat as git revision range.
     # Store SHAs in a temp file and iterate via 'while read' rather than
     # 'for sha in $revs', which depends on unquoted word-splitting and is
     # not portable to shells that don't enable SH_WORD_SPLIT by default.
     tmpfile=$(mktemp)
     revsfile=$(mktemp)
     trap 'rm -f "$tmpfile" "$revsfile"' EXIT

     if ! git log --format=%H "$@" > "$revsfile" 2>/dev/null; then
         printf "${RED}ERROR:${RST} invalid revision range: %s\n" "$*" >&2
         exit 1
     fi
     if [ ! -s "$revsfile" ]; then
         printf "no commits in range: %s\n" "$*"
         exit 0
     fi

     total=0
     failures=0

     while IFS= read -r sha; do
         total=$((total + 1))
         printf '\n--- %s: %s ---\n' "$sha" "$(git log -1 --format=%s "$sha")"
         git log -1 --format="%B" "$sha" > "$tmpfile"
         if ! check_message "$tmpfile"; then
             failures=$((failures + 1))
         fi
     done < "$revsfile"

     printf '\n--- Result: %d/%d passed ---\n' "$((total - failures))" "$total"
     [ "$failures" -eq 0 ]
     exit $?
 fi
	#!/bin/sh
	#
	# Validate commit messages against FFmpeg conventions.
	#
	# Based on lint_commit_msg.py from mpv (LGPL).
	# Original authors: Kacper Michajłow, Timo Rothenpieler
	#
	# This file is part of FFmpeg.
	#
	# FFmpeg is free software; you can redistribute it and/or modify
	# it under the terms of the GNU Lesser General Public License as published by
	# the Free Software Foundation; either version 2.1 of the License, or
	# (at your option) any later version.
	#
	# FFmpeg is distributed in the hope that it will be useful,
	# but WITHOUT ANY WARRANTY; without even the implied warranty of
	# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	# GNU Lesser General Public License for more details.
	#
	# You should have received a copy of the GNU Lesser General Public License
	# along with FFmpeg; if not, write to the Free Software Foundation, Inc.,
	# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
	#
	# Exit code 0 = all pass, non-zero = errors found.
	#
	# Usage:
	# Single message from stdin:
	# git log -1 --format="%B" <commit> \| sh tools/check_commit_msg.sh
	#
	# Single message from file (pre-commit commit-msg hook):
	# sh tools/check_commit_msg.sh .git/COMMIT_EDITMSG
	#
	# Multiple commits via revision range:
	# sh tools/check_commit_msg.sh HEAD~5..HEAD
	# sh tools/check_commit_msg.sh origin/master..my-branch
	# sh tools/check_commit_msg.sh -10 # last 10 commits
	#
	# Examples:
	# echo "avcodec/vvc: fix intra prediction" \| sh tools/check_commit_msg.sh
	# # => commit message OK
	#
	# echo "fix bug" \| sh tools/check_commit_msg.sh
	# # => ERROR: subject does not match 'component: description' pattern: fix bug
	#
	# Checks (errors block, warnings only print):
	# - Subject matches "component[/module]: description" pattern (error)
	# - No conventional-commits style (feat:/fix:/chore: etc.) (error)
	# - Blank line between subject and body (if body exists) (error)
	# - No duplicate Signed-off-by from same person (error)
	# - No multiple subject-like lines (2+) in body (squash-mess) (error)
	# - Subject line <= 120 characters (warning)
	# - No trailing whitespace on subject line (warning)
	# - Subject does not end with a period (warning)
	# - Prefix does not contain file extension (.c, .h, etc.) (warning)

	RED='\033[1;31m'
	YEL='\033[1;33m'
	RST='\033[0m'

	# --- Single-message validation (operates on a temp file) ---

	check_message() {
	msgfile=$1
	err=0
	warn_count=0

	error() {
	printf "${RED}ERROR:${RST} %s\n" "$1" >&2
	err=1
	}

	warning() {
	printf "${YEL}WARNING:${RST} %s\n" "$1" >&2
	warn_count=$((warn_count + 1))
	}

	# Check for empty message
	if ! grep -q '[^[:space:]]' "$msgfile"; then
	error "commit message is empty"
	return $err
	fi

	# Split into subject (first line) and the rest
	subject=$(head -n 1 "$msgfile")

	# --- Subject checks ---

	# Trailing whitespace on subject (second pattern is a literal tab)
	case "$subject" in
	" "\|" ")
	warning "trailing whitespace on subject line"
	;;
	esac

	# Subject format: component/module: description
	# Allow nested paths like avcodec/vvc/inter: or single component like doc:
	# Also allow "Merge", "Revert" and "Reapply" subjects used by forges
	# Patterns supported:
	# component: desc (avcodec/vvc: fix)
	# component modifier: desc (avcodec/vvc decode: fix)
	# component, component: desc (avformat/a, avcodec/b: fix)
	# .component: desc (.forgejo/CODEOWNERS: add)
	# {component}: desc ({lib{a,b}/x86/,}Makefile: fix)
	# COMP: a component token starting with a letter, at least 2 characters.
	COMP='[a-zA-Z][]a-zA-Z0-9_./{},*?\|()[-]+'
	case "$subject" in
	Merge\ \|Revert\ \|Reapply\ *)
	# Merge, revert and reapply commits get a pass on format checks
	;;
	*)
	# Require a non-empty description after ": " so that bare
	# "component:" or "component: " (no text) are rejected.
	if ! printf '%s\n' "$subject" \| grep -qE "^[{.]?${COMP}(, ${COMP})( +[a-zA-Z0-9_]+)*: [^[:space:]]"; then
	error "subject does not match 'component: description' pattern: $subject"
	fi

	# Do not use conventional-commits style (feat:/fix:/chore:/refactor:)
	if printf '%s\n' "$subject" \| grep -qEi '^(feat\|fix\|chore\|refactor)[!:(]'; then
	error "do not use conventional-commits style (feat:/fix:/chore:/refactor:)"
	fi

	# Prefix should not include file extension
	prefix=$(printf '%s\n' "$subject" \| sed -n 's/: .*//p')
	if printf '%s\n' "$prefix" \| grep -qE '[a-z0-9]\.(c\|h\|m\|texi)$'; then
	warning "prefix should not include file extension: $prefix"
	fi
	;;
	esac

	# Subject should not end with a period
	case "$subject" in
	*.)
	warning "subject should not end with a period"
	;;
	esac

	# Subject length
	subj_len=${#subject}
	if [ "$subj_len" -gt 120 ]; then
	warning "subject is $subj_len characters (> 120)"
	fi

	# --- Blank line between subject and body ---
	# Use sed to check line 2 directly; works regardless of trailing newline.
	second_line=$(sed -n '2p' "$msgfile")
	rest=$(sed -n '2,$p' "$msgfile")
	if [ -n "$rest" ]; then
	if [ -n "$second_line" ]; then
	error "missing blank line between subject and body"
	fi

	# Body is everything after the blank separator line
	body=$(tail -n +3 "$msgfile")
	else
	body=""
	fi

	# --- Squash-mess detection ---

	if [ -n "$body" ]; then
	# Multiple Signed-off-by from the same person
	sob_dups=$(printf '%s\n' "$body" \| grep -i '^Signed-off-by:' \| sort \| uniq -d)
	if [ -n "$sob_dups" ]; then
	error "duplicate Signed-off-by: $(printf '%s\n' "$sob_dups" \| head -n 1)"
	fi

	# Heuristic squash detection: count body lines that look like
	# additional commit subjects of the form "component/module: text".
	# Intentionally restricted to prefixes that contain '/' so that
	# prose definitions (e.g. "maximum: No restriction") and data
	# labels are not flagged as subjects; this trades recall for
	# precision and will not catch squash bodies made entirely of
	# single-component subjects like "doc: ..." or "configure: ...".
	# Match any non-space after ": " so lowercase subjects are counted too.
	# Exclude known trailer tags.
	subj_like_count=$(printf '%s\n' "$body" \
	\| grep -E '^[a-zA-Z][a-zA-Z0-9_./-]*/[a-zA-Z0-9_./-]+: [^[:space:]]' \
	\| grep -ivcE '^(Signed-off-by\|Reviewed-by\|Acked-by\|Tested-by\|CC\|Reported-by\|Co-authored-by\|Link\|Fixes\|Note\|Suggested-by\|Bug):')
	if [ "$subj_like_count" -ge 2 ]; then
	error "body contains $subj_like_count subject-like lines (squash-mess?)"
	fi
	fi

	if [ $err -eq 0 ] && [ $warn_count -eq 0 ]; then
	printf "commit message OK\n"
	fi

	return $err
	}

	# --- Main ---

	if [ $# -eq 0 ]; then
	# No argument: read a single message from stdin
	tmpfile=$(mktemp)
	trap 'rm -f "$tmpfile"' EXIT
	cat > "$tmpfile"
	check_message "$tmpfile"
	exit $?
	elif [ $# -eq 1 ] && [ -f "$1" ]; then
	# Single argument is an existing file: treat as commit message file
	# (used by pre-commit commit-msg hook passing .git/COMMIT_EDITMSG)
	check_message "$1"
	exit $?
	else
	# Argument(s) provided: treat as git revision range.
	# Store SHAs in a temp file and iterate via 'while read' rather than
	# 'for sha in $revs', which depends on unquoted word-splitting and is
	# not portable to shells that don't enable SH_WORD_SPLIT by default.
	tmpfile=$(mktemp)
	revsfile=$(mktemp)
	trap 'rm -f "$tmpfile" "$revsfile"' EXIT

	if ! git log --format=%H "$@" > "$revsfile" 2>/dev/null; then
	printf "${RED}ERROR:${RST} invalid revision range: %s\n" "$*" >&2
	exit 1
	fi
	if [ ! -s "$revsfile" ]; then
	printf "no commits in range: %s\n" "$*"
	exit 0
	fi

	total=0
	failures=0

	while IFS= read -r sha; do
	total=$((total + 1))
	printf '\n--- %s: %s ---\n' "$sha" "$(git log -1 --format=%s "$sha")"
	git log -1 --format="%B" "$sha" > "$tmpfile"
	if ! check_message "$tmpfile"; then
	failures=$((failures + 1))
	fi
	done < "$revsfile"

	printf '\n--- Result: %d/%d passed ---\n' "$((total - failures))" "$total"
	[ "$failures" -eq 0 ]
	exit $?
	fi