[1/3] mergetool-lib: use $XDG_CURRENT_DESKTOP to check GNOME
diff mbox series

Message ID 66a026ae678341fe7e93a89e22f76e24282cebaa.1596634463.git.gitgitgadget@gmail.com
State New
Headers show
Series
  • mergetool-lib: Don't use deprecated variable to detect GNOME
Related show

Commit Message

Andrew Klotz via GitGitGadget Aug. 5, 2020, 1:34 p.m. UTC
From: =?UTF-8?q?Marco=20Trevisan=20=28Trevi=C3=B1o=29?= <mail@3v1n0.net>

To list merge tool candidates we used to use a private GNOME env
variable (GNOME_DESKTOP_SESSION_ID) that has been deprecated for long time ago
and removed as part of GNOME 3.30.0 release [1].

So, git should instead check the XDG_CURRENT_DESKTOP env variable, that
is supported by all the desktop environments.

Since the variable is actually a colon-separated list of names that the current
desktop is known as, we need to go through all the values to ensure
we're using GNOME.

[1] https://gitlab.gnome.org/GNOME/gnome-session/-/commit/00e0e6226371d53f65

Signed-off-by: Marco Trevisan (Treviño) <mail@3v1n0.net>
---
 git-mergetool--lib.sh | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

Comments

Eric Sunshine Aug. 5, 2020, 8:58 p.m. UTC | #1
On Wed, Aug 5, 2020 at 3:51 PM Marco Trevisan (Treviño) via
GitGitGadget <gitgitgadget@gmail.com> wrote:
> To list merge tool candidates we used to use a private GNOME env
> variable (GNOME_DESKTOP_SESSION_ID) that has been deprecated for long time ago
> and removed as part of GNOME 3.30.0 release [1].
>
> So, git should instead check the XDG_CURRENT_DESKTOP env variable, that
> is supported by all the desktop environments.
>
> Since the variable is actually a colon-separated list of names that the current
> desktop is known as, we need to go through all the values to ensure
> we're using GNOME.
>
> Signed-off-by: Marco Trevisan (Treviño) <mail@3v1n0.net>
> ---
> diff --git a/git-mergetool--lib.sh b/git-mergetool--lib.sh
> @@ -266,6 +266,19 @@ run_merge_cmd () {
> +is_desktop () {
> +       IFS=':'

We usually want to restore the value of IFS after we're done with it.
For instance:

    OLDIFS=$IFS
    IFS=:

and then restore it before returning:

    IFS=$OLDIFS

> +       for desktop in ${XDG_CURRENT_DESKTOP}
> +       do
> +               if test "$desktop" = "$1"
> +               then
> +                       return 0
> +               fi
> +       done
> +
> +       return 1
> +}

Rather than looping and mucking with IFS, even easier would be:

is_desktop () {
    case ":$XDG_CURRENT_DESKTOP:" in
    *:$1:*) return 0 ;;
    *) return 1 ;;
    esac
}

But perhaps that's too magical for people?

> @@ -275,7 +288,7 @@ list_merge_tool_candidates () {
> -               if test -n "$GNOME_DESKTOP_SESSION_ID"
> +               if is_desktop "GNOME"

Why do we need to retire the $GNOME_DESKTOP_SESSION_ID check here,
thus penalizing people who might still be on an old version of GNOME?
It doesn't seem like it would be a maintenance burden to continue
checking it while also taking advantage of $XDG_CURRENT_DESKTOP:

    if test -n "$GNOME_DESKTOP_SESSION_ID" || is_desktop GNOME
Junio C Hamano Aug. 5, 2020, 10:14 p.m. UTC | #2
Eric Sunshine <sunshine@sunshineco.com> writes:

> Rather than looping and mucking with IFS, even easier would be:
>
> is_desktop () {
>     case ":$XDG_CURRENT_DESKTOP:" in
>     *:$1:*) return 0 ;;
>     *) return 1 ;;
>     esac
> }
>
> But perhaps that's too magical for people?

Nah, that is exactly how 'case' in shell is supposed to be used.

Thanks.
Marco Trevisan (Treviño) Aug. 6, 2020, 12:12 p.m. UTC | #3
Hi,

Il giorno mer 5 ago 2020 alle ore 22:58 Eric Sunshine
<sunshine@sunshineco.com> ha scritto:
>
> On Wed, Aug 5, 2020 at 3:51 PM Marco Trevisan (Treviño) via
> GitGitGadget <gitgitgadget@gmail.com> wrote:
> > To list merge tool candidates we used to use a private GNOME env
> > variable (GNOME_DESKTOP_SESSION_ID) that has been deprecated for long time ago
> > and removed as part of GNOME 3.30.0 release [1].
> >
> > So, git should instead check the XDG_CURRENT_DESKTOP env variable, that
> > is supported by all the desktop environments.
> >
> > Since the variable is actually a colon-separated list of names that the current
> > desktop is known as, we need to go through all the values to ensure
> > we're using GNOME.
> >
> > Signed-off-by: Marco Trevisan (Treviño) <mail@3v1n0.net>
> > ---
> > diff --git a/git-mergetool--lib.sh b/git-mergetool--lib.sh
> > @@ -266,6 +266,19 @@ run_merge_cmd () {
> > +is_desktop () {
> > +       IFS=':'
>
> We usually want to restore the value of IFS after we're done with it.
> For instance:
>
>     OLDIFS=$IFS
>     IFS=:
>
> and then restore it before returning:
>
>     IFS=$OLDIFS

Yeah, that's true and always a good practice, but it was never
happening in this file, so I followed the style.

> > +       for desktop in ${XDG_CURRENT_DESKTOP}
> > +       do
> > +               if test "$desktop" = "$1"
> > +               then
> > +                       return 0
> > +               fi
> > +       done
> > +
> > +       return 1
> > +}
>
> Rather than looping and mucking with IFS, even easier would be:
>
> is_desktop () {
>     case ":$XDG_CURRENT_DESKTOP:" in
>     *:$1:*) return 0 ;;
>     *) return 1 ;;
>     esac
> }
>
> But perhaps that's too magical for people?

Ok, fair enough, this is fine as well.

> > @@ -275,7 +288,7 @@ list_merge_tool_candidates () {
> > -               if test -n "$GNOME_DESKTOP_SESSION_ID"
> > +               if is_desktop "GNOME"
>
> Why do we need to retire the $GNOME_DESKTOP_SESSION_ID check here,
> thus penalizing people who might still be on an old version of GNOME?
> It doesn't seem like it would be a maintenance burden to continue
> checking it while also taking advantage of $XDG_CURRENT_DESKTOP:
>
>     if test -n "$GNOME_DESKTOP_SESSION_ID" || is_desktop GNOME

Ok, keeping this as well, it's even true that most people won't be in
gnome 2 these days, but not a problem to keep it around.

Patch
diff mbox series

diff --git a/git-mergetool--lib.sh b/git-mergetool--lib.sh
index 204a5acd66..be28fe375f 100644
--- a/git-mergetool--lib.sh
+++ b/git-mergetool--lib.sh
@@ -266,6 +266,19 @@  run_merge_cmd () {
 	fi
 }
 
+is_desktop () {
+	IFS=':'
+	for desktop in ${XDG_CURRENT_DESKTOP}
+	do
+		if test "$desktop" = "$1"
+		then
+			return 0
+		fi
+	done
+
+	return 1
+}
+
 list_merge_tool_candidates () {
 	if merge_mode
 	then
@@ -275,7 +288,7 @@  list_merge_tool_candidates () {
 	fi
 	if test -n "$DISPLAY"
 	then
-		if test -n "$GNOME_DESKTOP_SESSION_ID"
+		if is_desktop "GNOME"
 		then
 			tools="meld opendiff kdiff3 tkdiff xxdiff $tools"
 		else