Re: [PATCH] mergetool: add an option for writing to a temporary directory

> Teach mergetool to write files in a temporary directory when
> 'mergetool.writeToTemp' is true.
>
> This is helpful for tools such as Eclipse which cannot cope with
> multiple copies of the same file in the worktree.
>
> Suggested-by: Charles Bailey <charles@hashpling.org>
> Signed-off-by: David Aguilar <davvid@gmail.com>
> ---
> This patch is dependent on my previous mergetool patches:
> "use more conservative temporary..." and the subsequent --tool-help
> series.

>
>  Documentation/config.txt |  6 ++++++
>  git-mergetool.sh         | 35 +++++++++++++++++++++++++++++++----
>  2 files changed, 37 insertions(+), 4 deletions(-)
>
> diff --git a/Documentation/config.txt b/Documentation/config.txt
> index 04a1e2f..be6cf35 100644
> --- a/Documentation/config.txt
> +++ b/Documentation/config.txt
> @@ -1768,6 +1768,12 @@ mergetool.keepTemporaries::
>  	preserved, otherwise they will be removed after the tool has
>  	exited. Defaults to `false`.
>  
> +mergetool.writeToTemp::
> +	Git writes temporary 'BASE', 'LOCAL', and 'REMOTE' versions of
> +	conflicting files in the worktree by default.  Git will attempt
> +	to use a temporary directory for these files when set `true`.
> +	Defaults to `false`.
> +
>  mergetool.prompt::
>  	Prompt before each invocation of the merge resolution program.
>  
> diff --git a/git-mergetool.sh b/git-mergetool.sh
> index 10782b8..2b788c5 100755
> --- a/git-mergetool.sh
> +++ b/git-mergetool.sh
> @@ -37,6 +37,19 @@ base_present () {
>  	test -n "$base_mode"
>  }
>  
> +mergetool_tmpdir_init () {
> +	if test "$(git config --bool mergetool.writeToTemp)" != true
> +	then
> +		MERGETOOL_TMPDIR=.
> +		return 0
> +	fi
> +	if MERGETOOL_TMPDIR=$(mktemp -d -t "git-mergetool-XXXXXX" 2>/dev/null)
> +	then
> +		return 0
> +	fi
> +	die "error: mktemp is needed when 'mergetool.writeToTemp' is true"
> +}
> +
>  cleanup_temp_files () {
>  	if test "$1" = --save-backup
>  	then
> @@ -46,6 +59,10 @@ cleanup_temp_files () {
>  	else
>  		rm -f -- "$LOCAL" "$REMOTE" "$BASE" "$BACKUP"
>  	fi
> +	if test "$MERGETOOL_TMPDIR" != "."
> +	then
> +		rmdir "$MERGETOOL_TMPDIR"
> +	fi
>  }
>  
>  describe_file () {
> @@ -235,10 +252,20 @@ merge_file () {
>  		BASE=$MERGED
>  		ext=
>  	fi
> -	BACKUP="./${BASE}_BACKUP_$$$ext"
> -	LOCAL="./${BASE}_LOCAL_$$$ext"
> -	REMOTE="./${BASE}_REMOTE_$$$ext"
> -	BASE="./${BASE}_BASE_$$$ext"
> +
> +	mergetool_tmpdir_init
> +
> +	if test "$MERGETOOL_TMPDIR" != "."
> +	then
> +		# If we're using a temporary directory then write to the
> +		# top-level of that directory.
> +		BASE=${BASE##*/}
> +	fi
> +
> +	BACKUP="$MERGETOOL_TMPDIR/${BASE}_BACKUP_$$$ext"
> +	LOCAL="$MERGETOOL_TMPDIR/${BASE}_LOCAL_$$$ext"
> +	REMOTE="$MERGETOOL_TMPDIR/${BASE}_REMOTE_$$$ext"
> +	BASE="$MERGETOOL_TMPDIR/${BASE}_BASE_$$$ext"
>  
>  	base_mode=$(git ls-files -u -- "$MERGED" | awk '{if ($3==1) print $1;}')
>  	local_mode=$(git ls-files -u -- "$MERGED" | awk '{if ($3==2) print $1;}')