Hi Peff,
On Fri, 25 Nov 2016, Jeff King wrote:
> On Fri, Nov 25, 2016 at 06:41:23PM +0100, Johannes Schindelin wrote:
>
> > > Ah, I didn't realize that was a requirement. If this is going to be part
> > > of a release and real end-users are going to see it, that does make me
> > > think the config option is the better path (than the presence of some
> > > file), as it's our standard way of tweaking run-time behavior.
> >
> > So how do you easily switch back and forth between testing the old vs the
> > new difftool via the test suite?
>
> If it's for a specific tool, I'd consider teaching the test suite to run
> the whole script twice: once with the flag set and once without.
>
> That is sometimes more complicated, though, if the script creates many
> sub-repos. An environment variable might be more natural. If you already
> support flipping the default via config, you can probably do:
>
> GIT_CONFIG_PARAMETERS="'difftool.usebuiltin=true'"
> export GIT_CONFIG_PARAMETERS
Except that that does not work, of course. To figure out why, apply this
diff:
-- snip --
diff --git a/t/t7800-difftool.sh b/t/t7800-difftool.sh
index 17f3008277..27159f65f3 100755
--- a/t/t7800-difftool.sh
+++ b/t/t7800-difftool.sh
@@ -10,6 +10,9 @@ Testing basic diff tool invocation
. ./test-lib.sh
+echo "config $(git config difftool.usebuiltin)." >&2
+exit 1
+
difftool_test_setup ()
{
test_config diff.tool test-tool &&
diff --git a/t/test-lib.sh b/t/test-lib.sh
index 9980a46133..0ddeded92b 100644
--- a/t/test-lib.sh
+++ b/t/test-lib.sh
@@ -86,6 +86,7 @@ EDITOR=:
# /usr/xpg4/bin/sh and /bin/ksh to bail out. So keep the unsets
# deriving from the command substitution clustered with the other
# ones.
+echo "before $(git config difftool.usebuiltin)." >&2
unset VISUAL EMAIL LANGUAGE COLUMNS $("$PERL_PATH" -e '
my @env = keys %ENV;
my $ok = join("|", qw(
@@ -104,6 +105,7 @@ unset VISUAL EMAIL LANGUAGE COLUMNS $("$PERL_PATH" -e
'
my @vars = grep(/^GIT_/ && !/^GIT_($ok)/o, @env);
print join("\n", @vars);
')
+echo "after $(git config difftool.usebuiltin)." >&2
unset XDG_CONFIG_HOME
unset GITPERLLIB
[email protected]
-- snap --
and then weep at this output:
GIT_CONFIG_PARAMETERS="'difftool.usebuiltin=true'"; export
GIT_CONFIG_PARAMETERS; bash t7800-difftool.sh -i -v -x
before true.
after .
Initialized empty Git repository in
/home/virtualbox/git/git-for-windows/t/trash
directory.t7800-difftool/.git/
config .
FATAL: Unexpected exit with code 1
In other words, GIT_CONFIG_PARAMETERS is *explicitly scrubbed* from the
environment when we run our tests (by the code block between the "before"
and the "after" statements in the diff above).
Ciao,
Dscho
