[PATCH] mergetool: support absolute paths to tools by git config merge.<tool>path

[PATCH] mergetool: support absolute paths to tools by git config merge.<tool>path

[Steffen Prohaska]

This commit adds a mechanism to provide absolute paths to the
commands called by 'git mergetool'. A path can be specified
in the configuation variable merge.<toolname>path.

This mechanism is especially useful on Windows, where external
programs are unlikely to be in the path.

Signed-off-by: Steffen Prohaska <prohaska@zib.de>
---
 Documentation/git-mergetool.txt |    5 ++
 git-mergetool.sh                |   81 ++++++++++++++++++++++-----------------
 2 files changed, 51 insertions(+), 35 deletions(-)

diff --git a/Documentation/git-mergetool.txt b/Documentation/git-mergetool.txt
index 6c32c6d..6b97aaa 100644
--- a/Documentation/git-mergetool.txt
+++ b/Documentation/git-mergetool.txt
@@ -31,6 +31,11 @@ If a merge resolution program is not specified, 'git mergetool'
 will use the configuration variable merge.tool.  If the
 configuration variable merge.tool is not set, 'git mergetool'
 will pick a suitable default.
++
+You can explicitly provide a full path to the tool by setting the
+configuration variable merge.<tool>path. For example, you
+can configure the absolute path to kdiff3 by setting merge.kdiff3path.
+Otherise, 'git mergetool' assumes the tool is available in PATH.
 
 Author
 ------
diff --git a/git-mergetool.sh b/git-mergetool.sh
index 9f4f313..7f6c16f 100755
--- a/git-mergetool.sh
+++ b/git-mergetool.sh
@@ -192,10 +192,10 @@ merge_file () {
     case "$merge_tool" in
 	kdiff3)
 	    if base_present ; then
-		(kdiff3 --auto --L1 "$path (Base)" --L2 "$path (Local)" --L3 "$path (Remote)" \
+		("$merge_tool_path" --auto --L1 "$path (Base)" --L2 "$path (Local)" --L3 "$path (Remote)" \
 		    -o "$path" -- "$BASE" "$LOCAL" "$REMOTE" > /dev/null 2>&1)
 	    else
-		(kdiff3 --auto --L1 "$path (Local)" --L2 "$path (Remote)" \
+		("$merge_tool_path" --auto --L1 "$path (Local)" --L2 "$path (Remote)" \
 		    -o "$path" -- "$LOCAL" "$REMOTE" > /dev/null 2>&1)
 	    fi
 	    status=$?
@@ -203,35 +203,35 @@ merge_file () {
 	    ;;
 	tkdiff)
 	    if base_present ; then
-		tkdiff -a "$BASE" -o "$path" -- "$LOCAL" "$REMOTE"
+		"$merge_tool_path" -a "$BASE" -o "$path" -- "$LOCAL" "$REMOTE"
 	    else
-		tkdiff -o "$path" -- "$LOCAL" "$REMOTE"
+		"$merge_tool_path" -o "$path" -- "$LOCAL" "$REMOTE"
 	    fi
 	    status=$?
 	    save_backup
 	    ;;
 	meld|vimdiff)
 	    touch "$BACKUP"
-	    $merge_tool -- "$LOCAL" "$path" "$REMOTE"
+	    "$merge_tool_path" -- "$LOCAL" "$path" "$REMOTE"
 	    check_unchanged
 	    save_backup
 	    ;;
 	gvimdiff)
 		touch "$BACKUP"
-		gvimdiff -f -- "$LOCAL" "$path" "$REMOTE"
+		"$merge_tool_path" -f -- "$LOCAL" "$path" "$REMOTE"
 		check_unchanged
 		save_backup
 		;;
 	xxdiff)
 	    touch "$BACKUP"
 	    if base_present ; then
-		xxdiff -X --show-merged-pane \
+		"$merge_tool_path" -X --show-merged-pane \
 		    -R 'Accel.SaveAsMerged: "Ctrl-S"' \
 		    -R 'Accel.Search: "Ctrl+F"' \
 		    -R 'Accel.SearchForward: "Ctrl-G"' \
 		    --merged-file "$path" -- "$LOCAL" "$BASE" "$REMOTE"
 	    else
-		xxdiff -X --show-merged-pane \
+		"$merge_tool_path" -X --show-merged-pane \
 		    -R 'Accel.SaveAsMerged: "Ctrl-S"' \
 		    -R 'Accel.Search: "Ctrl+F"' \
 		    -R 'Accel.SearchForward: "Ctrl-G"' \
@@ -243,18 +243,18 @@ merge_file () {
 	opendiff)
 	    touch "$BACKUP"
 	    if base_present; then
-		opendiff "$LOCAL" "$REMOTE" -ancestor "$BASE" -merge "$path" | cat
+		"$merge_tool_path" "$LOCAL" "$REMOTE" -ancestor "$BASE" -merge "$path" | cat
 	    else
-		opendiff "$LOCAL" "$REMOTE" -merge "$path" | cat
+		"$merge_tool_path" "$LOCAL" "$REMOTE" -merge "$path" | cat
 	    fi
 	    check_unchanged
 	    save_backup
 	    ;;
 	emerge)
 	    if base_present ; then
-		emacs -f emerge-files-with-ancestor-command "$LOCAL" "$REMOTE" "$BASE" "$(basename "$path")"
+		"$merge_tool_path" -f emerge-files-with-ancestor-command "$LOCAL" "$REMOTE" "$BASE" "$(basename "$path")"
 	    else
-		emacs -f emerge-files-command "$LOCAL" "$REMOTE" "$(basename "$path")"
+		"$merge_tool_path" -f emerge-files-command "$LOCAL" "$REMOTE" "$(basename "$path")"
 	    fi
 	    status=$?
 	    save_backup
@@ -297,17 +297,23 @@ do
     shift
 done
 
+valid_tool() {
+	case "$1" in
+		kdiff3 | tkdiff | xxdiff | meld | opendiff | emerge | vimdiff | gvimdiff)
+			;; # happy
+		*)
+			return 1
+			;;
+	esac
+}
+
 if test -z "$merge_tool"; then
     merge_tool=`git config merge.tool`
-    case "$merge_tool" in
-	kdiff3 | tkdiff | xxdiff | meld | opendiff | emerge | vimdiff | gvimdiff | "")
-	    ;; # happy
-	*)
+    test -n "$merge_tool" || valid_tool "$merge_tool" || {
 	    echo >&2 "git config option merge.tool set to unknown tool: $merge_tool"
 	    echo >&2 "Resetting to default..."
 	    unset merge_tool
-	    ;;
-    esac
+    }
 fi
 
 if test -z "$merge_tool" ; then
@@ -345,24 +351,29 @@ if test -z "$merge_tool" ; then
     fi
 fi
 
-case "$merge_tool" in
-    kdiff3|tkdiff|meld|xxdiff|vimdiff|gvimdiff|opendiff)
-	if ! type "$merge_tool" > /dev/null 2>&1; then
-	    echo "The merge tool $merge_tool is not available"
-	    exit 1
-	fi
-	;;
-    emerge)
-	if ! type "emacs" > /dev/null 2>&1; then
-	    echo "Emacs is not available"
-	    exit 1
-	fi
-	;;
-    *)
-	echo "Unknown merge tool: $merge_tool"
+valid_tool "$merge_tool" || {
+	echo >&2 "Unknown merge_tool $merge_tool"
 	exit 1
-	;;
-esac
+}
+
+if test -z "$merge_tool_path" ; then
+	merge_tool_path=`git config merge.${merge_tool}path`
+	if test -z "$merge_tool_path" ; then
+		case "$merge_tool" in
+			emerge)
+				merge_tool_path=emacs
+				;;
+			*)
+				merge_tool_path=$merge_tool
+				;;
+		esac
+	fi
+fi
+
+if ! type "$merge_tool_path" > /dev/null 2>&1; then
+    echo "The merge tool $merge_tool is not available as '$merge_tool_path'"
+    exit 1
+fi
 
 if test $# -eq 0 ; then
 	files=`git ls-files -u | sed -e 's/^[^	]*	//' | sort -u`
-- 
1.5.3.3.127.g40d17

[PATCH] mergetool: add support for ECMerge

[Steffen Prohaska]

Add support for ECMerge available from
http://www.elliecomputing.com/Products/merge_overview.asp

Signed-off-by: Steffen Prohaska <prohaska@zib.de>
---
 Documentation/git-mergetool.txt |    2 +-
 git-mergetool.sh                |   12 +++++++++++-
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/Documentation/git-mergetool.txt b/Documentation/git-mergetool.txt
index 6b97aaa..ece7718 100644
--- a/Documentation/git-mergetool.txt
+++ b/Documentation/git-mergetool.txt
@@ -25,7 +25,7 @@ OPTIONS
 -t or --tool=<tool>::
 	Use the merge resolution program specified by <tool>.
 	Valid merge tools are:
-	kdiff3, tkdiff, meld, xxdiff, emerge, vimdiff, gvimdiff, and opendiff
+	kdiff3, tkdiff, meld, xxdiff, emerge, vimdiff, gvimdiff, ecmerge, and opendiff
 +
 If a merge resolution program is not specified, 'git mergetool'
 will use the configuration variable merge.tool.  If the
diff --git a/git-mergetool.sh b/git-mergetool.sh
index 7f6c16f..39f6595 100755
--- a/git-mergetool.sh
+++ b/git-mergetool.sh
@@ -250,6 +250,16 @@ merge_file () {
 	    check_unchanged
 	    save_backup
 	    ;;
+	ecmerge)
+	    touch "$BACKUP"
+	    if base_present; then
+		"$merge_tool_path" "$BASE" "$LOCAL" "$REMOTE" --mode=merge3 --to="$path"
+	    else
+		"$merge_tool_path" "$LOCAL" "$REMOTE" --mode=merge2 --to="$path"
+	    fi
+	    check_unchanged
+	    save_backup
+	    ;;
 	emerge)
 	    if base_present ; then
 		"$merge_tool_path" -f emerge-files-with-ancestor-command "$LOCAL" "$REMOTE" "$BASE" "$(basename "$path")"
@@ -299,7 +309,7 @@ done
 
 valid_tool() {
 	case "$1" in
-		kdiff3 | tkdiff | xxdiff | meld | opendiff | emerge | vimdiff | gvimdiff)
+		kdiff3 | tkdiff | xxdiff | meld | opendiff | emerge | vimdiff | gvimdiff | ecmerge)
 			;; # happy
 		*)
 			return 1
-- 
1.5.3.3.127.g40d17

Re: [PATCH] mergetool: add support for ECMerge

[Theodore Tso]

On Mon, Oct 08, 2007 at 11:22:41PM +0200, Steffen Prohaska wrote:
> Add support for ECMerge available from
> http://www.elliecomputing.com/Products/merge_overview.asp

Hmm.  A propietary merge tool.  It's not that much code, so I guess....

I note though that it claims on the web page that they are integrated
with "most famous SCM's", but they don't include git.  If we add this
support, are they going to change their web page?  :-)

Also, ECmerge is supported on Linux, Solaris, MacOS X, and Windows.
Which platforms have you tested on?  My guess is that if it works on
Linux, it'll probably work on Solaris and MacOS, but is it a fair
guess you haven't tested under Windows?  Not that most Windows systems
are going to be able to use git-mergetool since it's a bash script,
unless they are using Cygwin or some such.

       	    	      	     	     - Ted

Re: [PATCH] mergetool: support absolute paths to tools by git config merge.<tool>path

[Theodore Tso]

On Mon, Oct 08, 2007 at 11:22:40PM +0200, Steffen Prohaska wrote:
> This commit adds a mechanism to provide absolute paths to the
> commands called by 'git mergetool'. A path can be specified
> in the configuation variable merge.<toolname>path.

This patch doesn't work the config file doesn't specify an explicit
mergetool via merge.tool.   The reason for that is this loop:

    for i in $merge_tool_candidates; do
        if test $i = emerge ; then
            cmd=emacs
        else
            cmd=$i
        fi
        if type $cmd > /dev/null 2>&1; then
            merge_tool=$i
            break
        fi
    done

is only checking to see if $cmd is in the path; it's not looking up
the merge.<toolname>path variable in this loop.

I guess the other question is whether we would be better off simply
telling the user to specify an absolute pathname in merge.tool, and
then having git-mergetool strip off the directory path via basename,
and then on window systems, stripping off the .EXE or .COM suffix, and
then downcasing the name so that something like "C:\Program
Files\ECMerge\ECMerge.exe" gets translated to "ecmerge".  Would I be
right in guessing that the reason why you used merge.<toolname>path
approach was to avoid this messy headache?

					- Ted

Re: [PATCH] mergetool: support absolute paths to tools by git config merge.<tool>path

[Frank Lichtenheld]

On Mon, Oct 08, 2007 at 11:22:40PM +0200, Steffen Prohaska wrote:
> This commit adds a mechanism to provide absolute paths to the
> commands called by 'git mergetool'. A path can be specified
> in the configuation variable merge.<toolname>path.

Why not merge.<toolname>.path?
This would it make easy to introduce new variables of the form
merge.<toolname>.<var> later if needed. I also think it is more
consistent with names of existing configuration variables.
(think branch.<name>.<var> or remote.<name>.<var>)

Gruesse,
-- 
Frank Lichtenheld <frank@lichtenheld.de>
www: http://www.djpig.de/

Re: [PATCH] mergetool: support absolute paths to tools by git config merge.<tool>path

[Theodore Tso]

On Mon, Oct 08, 2007 at 05:57:29PM -0400, Theodore Tso wrote:
> This patch doesn't work the config file doesn't specify an explicit
> mergetool via merge.tool.   The reason for that is this loop:

Err, let me try that again.  "This patch doesn't work IF the config
file doesn't specify an explicit > mergetool via merge.tool."

Sorry about the missing conjuction; the sentence doesn't make much
sense without it...

						- Ted

Re: [PATCH] mergetool: add support for ECMerge

[Steffen Prohaska]

On Oct 8, 2007, at 11:44 PM, Theodore Tso wrote:

> On Mon, Oct 08, 2007 at 11:22:41PM +0200, Steffen Prohaska wrote:
>> Add support for ECMerge available from
>> http://www.elliecomputing.com/Products/merge_overview.asp
>
> Hmm.  A propietary merge tool.  It's not that much code, so I  
> guess....
>
> I note though that it claims on the web page that they are integrated
> with "most famous SCM's", but they don't include git.  If we add this
> support, are they going to change their web page?  :-)

You may even apply for a free (as beer) license if you contribute
to open source projects:

http://www.elliecomputing.com/Community/opensource.asp

I didn't try this, so I can't say how this works in practice.

> Also, ECmerge is supported on Linux, Solaris, MacOS X, and Windows.
> Which platforms have you tested on?

Windows. Haven't tested Unix systems yet.

> My guess is that if it works on
> Linux, it'll probably work on Solaris and MacOS, but is it a fair
> guess you haven't tested under Windows?  Not that most Windows systems
> are going to be able to use git-mergetool since it's a bash script,
> unless they are using Cygwin or some such.

I work on the msysgit project and I'd like to have mergetool
available before I advertise git on Windows. It makes merging
so much easier ;)

	Steffen

Re: [PATCH] mergetool: support absolute paths to tools by git config merge.<tool>path

[Steffen Prohaska]

On Oct 8, 2007, at 11:57 PM, Theodore Tso wrote:

> On Mon, Oct 08, 2007 at 11:22:40PM +0200, Steffen Prohaska wrote:
>> This commit adds a mechanism to provide absolute paths to the
>> commands called by 'git mergetool'. A path can be specified
>> in the configuation variable merge.<toolname>path.
>
> This patch doesn't work if the config file doesn't specify an explicit
> mergetool via merge.tool.   The reason for that is this loop:
>
>     for i in $merge_tool_candidates; do
>         if test $i = emerge ; then
>             cmd=emacs
>         else
>             cmd=$i
>         fi
>         if type $cmd > /dev/null 2>&1; then
>             merge_tool=$i
>             break
>         fi
>     done
>
> is only checking to see if $cmd is in the path; it's not looking up
> the merge.<toolname>path variable in this loop.

I didn't change the automatic detection. It should work as before.
That is it continues to assume that merge tools are in PATH.

Is you expectation that git-mergetool should also consider the
absolute paths provided in merge.<toolname>path?

When I wrote the patch I had in mind that people will set the
merge.tool explicitly if they provide an absolute path. Automatic
detection would only be used if nothing is configured. In this
case a tool must be in PATH or would not be found.


> I guess the other question is whether we would be better off simply
> telling the user to specify an absolute pathname in merge.tool, and
> then having git-mergetool strip off the directory path via basename,
> and then on window systems, stripping off the .EXE or .COM suffix, and
> then downcasing the name so that something like "C:\Program
> Files\ECMerge\ECMerge.exe" gets translated to "ecmerge".  Would I be
> right in guessing that the reason why you used merge.<toolname>path
> approach was to avoid this messy headache?

Yes. The program to start ECMerge on Windows is called 'guimerge.exe'.
Hard to derive a sensible short name from this.

So I don't think that an automatic translation is an option. I prefer
to provide the absolute paths.

Absolute paths have another advantage. You can set several of them
and choose a tool on the command line. Maybe you have several tools
you want to try. Or you hacking with someone else who preferes a
different tool. Or you just want to give a demo. I see
merge.<toolname>path more as a database associating absolute paths
with the shortnames.

My mental model is as follows:
1) merge.tool selects the mechanism needed to call the tool, that is
command line arguments, how merge result is passed, ...
2) merge.<toolname>path provides additional information how to locate
the selected tool in the filesystem.

The two points are somewhat orthogonal. I'd not fuse them into one.

	Steffen

Re: [PATCH] mergetool: support absolute paths to tools by git config merge.<tool>path

[Steffen Prohaska]

On Oct 9, 2007, at 12:00 AM, Frank Lichtenheld wrote:

> On Mon, Oct 08, 2007 at 11:22:40PM +0200, Steffen Prohaska wrote:
>> This commit adds a mechanism to provide absolute paths to the
>> commands called by 'git mergetool'. A path can be specified
>> in the configuation variable merge.<toolname>path.
>
> Why not merge.<toolname>.path?
>
> This would it make easy to introduce new variables of the form
> merge.<toolname>.<var> later if needed. I also think it is more
> consistent with names of existing configuration variables.
> (think branch.<name>.<var> or remote.<name>.<var>)

Looks more beautiful on the command line but a bit more complex
in the config file. But I like the idea.

Maybe mergetool.<tool>.path is even a better choice? It clearly
indicate the relationship with mergetool. We could explain:

'The variable merge.tool = <tool> refers to a tool that can
be further specified in mergetool.<tool>.path.'

	Steffen

Re: [PATCH] mergetool: support absolute paths to tools by git config merge.<tool>path

[Johannes Schindelin]

Hi,

On Mon, 8 Oct 2007, Steffen Prohaska wrote:

> This commit adds a mechanism to provide absolute paths to the
> commands called by 'git mergetool'. A path can be specified
> in the configuation variable merge.<toolname>path.

Would it not be more in line with all other config variables if it was 
written merge.<toolname>.path?  (Indeed, I thought your subject line 
contained a typo when I read it first.)

Ciao,
Dscho

Re: [PATCH] mergetool: add support for ECMerge

[Johannes Schindelin]

Hi,

On Tue, 9 Oct 2007, Steffen Prohaska wrote:

> I work on the msysgit project and I'd like to have mergetool available 
> before I advertise git on Windows. It makes merging so much easier ;)

I would _hate_ to rely on a closed source program (in addition to Windows 
itself) in msysGit.

And it seems that you cannot even get ECMerge for free in general.

What does TortoiseCVS use?

Ciao,
Dscho

Re: [PATCH] mergetool: add support for ECMerge

[Steffen Prohaska]

On Oct 9, 2007, at 2:37 PM, Johannes Schindelin wrote:

> On Tue, 9 Oct 2007, Steffen Prohaska wrote:
>
>> I work on the msysgit project and I'd like to have mergetool  
>> available
>> before I advertise git on Windows. It makes merging so much easier ;)
>
> I would _hate_ to rely on a closed source program (in addition to  
> Windows
> itself) in msysGit.

It's only an option. You can also choose kdiff3 if you like, or  
vimdiff or
emacs merge. But personally, I prefer ECMerge because is seems to  
support
a faster and safer workflow (at least for me).

Before submitted this patch I thought about a general mechanism to  
easily
specify any tool that supports command line argument. But just adding  
them
tool by tool as needed looks easier to me, and hopefully to the user. We
can include the correct command line in git-mergetool and only require
the location of the program from the user.


> And it seems that you cannot even get ECMerge for free in general.

True. But does it matter? I can't get Windows for free and git runs  
on it.


> What does TortoiseCVS use?

Don't know.

	Steffen

Re: [PATCH] mergetool: add support for ECMerge

[Alan Hadsell]

On 10/9/07, Johannes Schindelin <Johannes.Schindelin@gmx.de> wrote:

> What does TortoiseCVS use?

They don't actually include it in the package, but they recommend
WinMerge http://winmerge.org/, which is free (GPL).

-- 
Alan Hadsell

Re: [PATCH] mergetool: add support for ECMerge

[Steffen Prohaska]

On Oct 9, 2007, at 3:03 PM, Alan Hadsell wrote:

> On 10/9/07, Johannes Schindelin <Johannes.Schindelin@gmx.de> wrote:
>
>> What does TortoiseCVS use?
>
> They don't actually include it in the package, but they recommend
> WinMerge http://winmerge.org/, which is free (GPL).

WinMerge doesn't support 3-way merges. At least I cannot find any
indication for 3-way in the manual [1] and the comparison at [2] also
tells that WinMerge doesn't support 3-way.

	Steffen

[1] http://winmerge.org/2.6/manual/CompareFiles.html
[2] http://en.wikipedia.org/wiki/Comparison_of_file_comparison_tools

Re: [PATCH] mergetool: add support for ECMerge

[Alan Hadsell]

Steffen Prohaska writes:

> WinMerge doesn't support 3-way merges. At least I cannot find any
> indication for 3-way in the manual [1] and the comparison at [2] also
> tells that WinMerge doesn't support 3-way.

>From their FAQ:

Does WinMerge support merging three files? Sometimes it is called
3-way merge, where one file is ancestor. This would be useful for
version control!

Unfortunately not. We acknowledge it would be good feature but have no
plans to implement it in near future. This can be somewhat worked
around by using two WinMerge instances. (One developer has begun
preliminary work on this feature, but it is not yet available, even in
experimental releases.)