[v2] mklog: handle Signed-Off-By, minor cleanup

  Consider Signed-Off-By lines as part of the ending of the initial
commit to avoid having these in the middle of the log when the
changelog part is injected after.

This is particularly usefull with:

 $ git gcc-commit-mklog --amend -s

that can be used to create the changelog and add the Signed-Off-By line.

Also applies most of the shellcheck suggestions on the
prepare-commit-msg hook.

contrib/ChangeLog:

	* mklog.py: Leave SOB lines after changelog.
	* prepare-commit-msg: Apply most shellcheck suggestions.

Signed-off-by: Marc Poulhiès <dkm@kataplop.net>
---
Previous version was missing the ChangeLog.

This command is used in particular during the dev of the frontend
for the Rust language (see r13-7099-g4b25fc15b925f8 as an example
of a SoB ending in the middle of the commit message).

Ok for master?

 contrib/mklog.py           | 34 +++++++++++++++++++++++++++++-----
 contrib/prepare-commit-msg | 20 ++++++++++----------
 2 files changed, 39 insertions(+), 15 deletions(-)
  

Marc Poulhiès via Gcc-patches <gcc-patches@gcc.gnu.org> writes:
> Consider Signed-Off-By lines as part of the ending of the initial
> commit to avoid having these in the middle of the log when the
> changelog part is injected after.
>
> This is particularly usefull with:
>
>  $ git gcc-commit-mklog --amend -s
>
> that can be used to create the changelog and add the Signed-Off-By line.
>
> Also applies most of the shellcheck suggestions on the
> prepare-commit-msg hook.
>
> contrib/ChangeLog:
>
> 	* mklog.py: Leave SOB lines after changelog.
> 	* prepare-commit-msg: Apply most shellcheck suggestions.
>
> Signed-off-by: Marc Poulhiès <dkm@kataplop.net>
> ---
> Previous version was missing the ChangeLog.
>
> This command is used in particular during the dev of the frontend
> for the Rust language (see r13-7099-g4b25fc15b925f8 as an example
> of a SoB ending in the middle of the commit message).
>
> Ok for master?
>
>  contrib/mklog.py           | 34 +++++++++++++++++++++++++++++-----
>  contrib/prepare-commit-msg | 20 ++++++++++----------
>  2 files changed, 39 insertions(+), 15 deletions(-)
>
> diff --git a/contrib/mklog.py b/contrib/mklog.py
> index 777212c98d7..e5cc69e0d0a 100755
> --- a/contrib/mklog.py
> +++ b/contrib/mklog.py
> @@ -41,7 +41,34 @@ from unidiff import PatchSet
>  
>  LINE_LIMIT = 100
>  TAB_WIDTH = 8
> -CO_AUTHORED_BY_PREFIX = 'co-authored-by: '
> +
> +# Initial commit:
> +#   +--------------------------------------------------+
> +#   | gccrs: Some title                                |
> +#   |                                                  | This is the "start"
> +#   | This is some text explaining the commit.         |
> +#   | There can be several lines.                      |
> +#   |                                                  |<------------------->
> +#   | Signed-off-by: My Name <my@mail.com>             | This is the "end"
> +#   +--------------------------------------------------+
> +#
> +# Results in:
> +#   +--------------------------------------------------+
> +#   | gccrs: Some title                                |
> +#   |                                                  |
> +#   | This is some text explaining the commit.         | This is the "start"
> +#   | There can be several lines.                      |
> +#   |                                                  |<------------------->
> +#   | gcc/rust/ChangeLog:                              |
> +#   |                                                  | This is the generated
> +#   |         * some_file (bla):                       | ChangeLog part
> +#   |         (foo):                                   |
> +#   |                                                  |<------------------->
> +#   | Signed-off-by: My Name <my@mail.com>             | This is the "end"
> +#   +--------------------------------------------------+
> +
> +# this regex matches the first line of the "end" in the initial commit message
> +FIRST_LINE_OF_END_RE = re.compile('(?i)^(signed-off-by|co-authored-by|#): ')

The current code only requires an initial "#", rather than an initial "#: ".
Is that a deliberate change?

The patch LGTM apart from that.

Thanks,
Richard

>  pr_regex = re.compile(r'(\/(\/|\*)|[Cc*!])\s+(?P<pr>PR [a-z+-]+\/[0-9]+)')
>  prnum_regex = re.compile(r'PR (?P<comp>[a-z+-]+)/(?P<num>[0-9]+)')
> @@ -330,10 +357,7 @@ def update_copyright(data):
>  
>  
>  def skip_line_in_changelog(line):
> -    if line.lower().startswith(CO_AUTHORED_BY_PREFIX) or line.startswith('#'):
> -        return False
> -    return True
> -
> +    return FIRST_LINE_OF_END_RE.match(line) == None
>  
>  if __name__ == '__main__':
>      extra_args = os.getenv('GCC_MKLOG_ARGS')
> diff --git a/contrib/prepare-commit-msg b/contrib/prepare-commit-msg
> index 48c9dad3c6f..1e94706ba40 100755
> --- a/contrib/prepare-commit-msg
> +++ b/contrib/prepare-commit-msg
> @@ -32,11 +32,11 @@ if ! [ -f "$COMMIT_MSG_FILE" ]; then exit 0; fi
>  # Don't do anything unless requested to.
>  if [ -z "$GCC_FORCE_MKLOG" ]; then exit 0; fi
>  
> -if [ -z "$COMMIT_SOURCE" ] || [ $COMMIT_SOURCE = template ]; then
> +if [ -z "$COMMIT_SOURCE" ] || [ "$COMMIT_SOURCE" = template ]; then
>      # No source or "template" means new commit.
>      cmd="diff --cached"
>  
> -elif [ $COMMIT_SOURCE = message ]; then
> +elif [ "$COMMIT_SOURCE" = message ]; then
>      # "message" means -m; assume a new commit if there are any changes staged.
>      if ! git diff --cached --quiet; then
>  	cmd="diff --cached"
> @@ -44,23 +44,23 @@ elif [ $COMMIT_SOURCE = message ]; then
>  	cmd="diff --cached HEAD^"
>      fi
>  
> -elif [ $COMMIT_SOURCE = commit ]; then
> +elif [ "$COMMIT_SOURCE" = commit ]; then
>      # The message of an existing commit.  If it's HEAD, assume --amend;
>      # otherwise, assume a new commit with -C.
> -    if [ $SHA1 = HEAD ]; then
> +    if [ "$SHA1" = HEAD ]; then
>  	cmd="diff --cached HEAD^"
>  	if [ "$(git config gcc-config.mklog-hook-type)" = "smart-amend" ]; then
>  	    # Check if the existing message still describes the staged changes.
>  	    f=$(mktemp /tmp/git-commit.XXXXXX) || exit 1
> -	    git log -1 --pretty=email HEAD > $f
> -	    printf '\n---\n\n' >> $f
> -	    git $cmd >> $f
> +	    git log -1 --pretty=email HEAD > "$f"
> +	    printf '\n---\n\n' >> "$f"
> +	    git $cmd >> "$f"
>  	    if contrib/gcc-changelog/git_email.py "$f" >/dev/null 2>&1; then
>  		# Existing commit message is still OK for amended commit.
> -		rm $f
> +		rm "$f"
>  		exit 0
>  	    fi
> -	    rm $f
> +	    rm "$f"
>  	fi
>      else
>  	cmd="diff --cached"
> @@ -72,7 +72,7 @@ fi
>  
>  # Save diff to a file if requested.
>  DIFF_FILE=$(git config gcc-config.diff-file)
> -if ! [ -z "$DIFF_FILE" ]; then
> +if [ -n "$DIFF_FILE" ]; then
>      tee="tee $DIFF_FILE"
>  else
>      tee="cat"