Merge branch 'maint'

* maint:
  rebase -i: clarify in-editor documentation of "exec"
  tests: sanitize more git environment variables
  fast-import: treat filemodify with empty tree as delete
  rebase: give a better error message for bogus branch
  rebase: use explicit "--" with checkout

Conflicts:
	t/t9300-fast-import.sh

t/t9300-fast-import.sh

@@ -919,6 +919,48 @@ test_expect_success \
 	 git diff-tree -C --find-copies-harder -r N4 N6 >actual &&
 	 compare_diff_raw expect actual'
 
+test_expect_success \
+	'N: delete directory by copying' \
+	'cat >expect <<-\EOF &&
+	OBJID
+	:100644 000000 OBJID OBJID D	foo/bar/qux
+	OBJID
+	:000000 100644 OBJID OBJID A	foo/bar/baz
+	:000000 100644 OBJID OBJID A	foo/bar/qux
+	EOF
+	 empty_tree=$(git mktree </dev/null) &&
+	 cat >input <<-INPUT_END &&
+	commit refs/heads/N-delete
+	committer $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> $GIT_COMMITTER_DATE
+	data <<COMMIT
+	collect data to be deleted
+	COMMIT
+
+	deleteall
+	M 100644 inline foo/bar/baz
+	data <<DATA_END
+	hello
+	DATA_END
+	C "foo/bar/baz" "foo/bar/qux"
+	C "foo/bar/baz" "foo/bar/quux/1"
+	C "foo/bar/baz" "foo/bar/quuux"
+	M 040000 $empty_tree foo/bar/quux
+	M 040000 $empty_tree foo/bar/quuux
+
+	commit refs/heads/N-delete
+	committer $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> $GIT_COMMITTER_DATE
+	data <<COMMIT
+	delete subdirectory
+	COMMIT
+
+	M 040000 $empty_tree foo/bar/qux
+	INPUT_END
+	 git fast-import <input &&
+	 git rev-list N-delete |
+		git diff-tree -r --stdin --root --always |
+		sed -e "s/$_x40/OBJID/g" >actual &&
+	 test_cmp expect actual'
+
 test_expect_success \
 	'N: modify copied tree' \
 	'cat >expect <<-\EOF &&

t/test-lib.sh

@@ -70,6 +70,9 @@ unset GIT_NOTES_REF
 unset GIT_NOTES_DISPLAY_REF
 unset GIT_NOTES_REWRITE_REF
 unset GIT_NOTES_REWRITE_MODE
+unset GIT_REFLOG_ACTION
+unset GIT_CHERRY_PICK_HELP
+unset GIT_QUIET
 GIT_MERGE_VERBOSITY=5
 export GIT_MERGE_VERBOSITY
 export GIT_AUTHOR_EMAIL GIT_AUTHOR_NAME