difftool--helper: Remove use of the GIT_MERGE_TOOL variable

An undocumented mis-feature in git-difftool is that it allows you
to specify a default difftool by setting GIT_MERGE_TOOL.
This behavior was never documented and was included as an
oversight back when git-difftool was maintained outside of git.

git-mergetool never honored GIT_MERGE_TOOL so neither should
git-difftool.

Signed-off-by: David Aguilar <davvid@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/git-difftool--helper.sh b/git-difftool--helper.sh
index 1b138083d3642af596fe56a74c4f98321e6135fc..3621f28c7969b7848e3fbcac49647f32028f18e7 100755 (executable)
--- a/git-difftool--helper.sh
+++ b/git-difftool--helper.sh
@@ -40,11 +40,10 @@ launch_merge_tool () {
        run_merge_tool "$merge_tool"
 }
 
-# Allow GIT_DIFF_TOOL and GIT_MERGE_TOOL to provide default values
-test -n "$GIT_MERGE_TOOL" && merge_tool="$GIT_MERGE_TOOL"
-test -n "$GIT_DIFF_TOOL" && merge_tool="$GIT_DIFF_TOOL"
-
-if test -z "$merge_tool"; then
+# GIT_DIFF_TOOL indicates that --tool=... was specified
+if test -n "$GIT_DIFF_TOOL"; then
+       merge_tool="$GIT_DIFF_TOOL"
+else
        merge_tool="$(get_merge_tool)" || exit
 fi
 

diff --git a/t/t7800-difftool.sh b/t/t7800-difftool.sh
index 9bf6c98c54f368dfc837a8c5c374021269f20707..eca51a8fe8090e22f49b3c983a95fe1388be4584 100755 (executable)
--- a/t/t7800-difftool.sh
+++ b/t/t7800-difftool.sh
@@ -32,7 +32,6 @@ restore_test_defaults()
        # Restores the test defaults used by several tests
        remove_config_vars
        unset GIT_DIFF_TOOL
-       unset GIT_MERGE_TOOL
        unset GIT_DIFFTOOL_PROMPT
        unset GIT_DIFFTOOL_NO_PROMPT
        git config diff.tool test-tool &&
@@ -107,15 +106,7 @@ test_expect_success 'GIT_DIFF_TOOL overrides' '
        git config diff.tool bogus-tool &&
        git config merge.tool bogus-tool &&
 
-       GIT_MERGE_TOOL=test-tool &&
-       export GIT_MERGE_TOOL &&
-       diff=$(git difftool --no-prompt branch) &&
-       test "$diff" = "branch" &&
-       unset GIT_MERGE_TOOL &&
-
-       GIT_MERGE_TOOL=bogus-tool &&
        GIT_DIFF_TOOL=test-tool &&
-       export GIT_MERGE_TOOL &&
        export GIT_DIFF_TOOL &&
 
        diff=$(git difftool --no-prompt branch) &&