pathspec: warn on empty strings as pathspec

An empty string as a pathspec element matches all paths.  A buggy
script, however, could accidentally assign an empty string to a
variable that then gets passed to a Git command invocation, e.g.:

	path=... compute a path to be removed in $path ...
        git rm -r "$paht"

which would unintentionally remove all paths in the current
directory.

The fix for this issue requires a two-step approach. As there may be
existing scripts that knowingly use empty strings in this manner,
the first step simply gives a warning that (1) tells that an empty
string will become an invalid pathspec element and (2) asks the user
to use "." if they mean to match all.

For step two, a follow-up patch several release cycles later will
remove the warning and throw an error instead.

This patch is the first step.

Signed-off-by: Emily Xie <emilyxxie@gmail.com>
Reported-by: David Turner <novalis@novalis.org>
Mentored-by: Michail Denchev <mdenchev@gmail.com>
Thanks-to: Sarah Sharp <sarah@thesharps.us> and James Sharp <jamey@minilop.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/pathspec.c b/pathspec.c
index c9e9b6c0778c755fcade1430cf674dfd867050f1..729df9f385fd2542d7b889b010fe33dfc8ddd019 100644 (file)
--- a/pathspec.c
+++ b/pathspec.c
@@ -364,7 +364,7 @@ void parse_pathspec(struct pathspec *pathspec,
 {
        struct pathspec_item *item;
        const char *entry = argv ? *argv : NULL;
-       int i, n, prefixlen, nr_exclude = 0;
+       int i, n, prefixlen, warn_empty_string, nr_exclude = 0;
 
        memset(pathspec, 0, sizeof(*pathspec));
 
@@ -402,8 +402,15 @@ void parse_pathspec(struct pathspec *pathspec,
        }
 
        n = 0;
-       while (argv[n])
+       warn_empty_string = 1;
+       while (argv[n]) {
+               if (*argv[n] == '\0' && warn_empty_string) {
+                       warning(_("empty strings as pathspecs will be made invalid in upcoming releases. "
+                                 "please use . instead if you meant to match all paths"));
+                       warn_empty_string = 0;
+               }
                n++;
+       }
 
        pathspec->nr = n;
        ALLOC_ARRAY(pathspec->items, n);

diff --git a/t/t3600-rm.sh b/t/t3600-rm.sh
index d046d98aec61748ad936515807f28f77600f630e..14f0edca2b6f67e6ae98379702b5566e4083d8e0 100755 (executable)
--- a/t/t3600-rm.sh
+++ b/t/t3600-rm.sh
@@ -881,4 +881,9 @@ test_expect_success 'rm files with two different errors' '
        test_i18ncmp expect actual
 '
 
+test_expect_success 'rm empty string should invoke warning' '
+       git rm -rf "" 2>output &&
+       test_i18ngrep "warning: empty strings" output
+'
+
 test_done

diff --git a/t/t3700-add.sh b/t/t3700-add.sh
index f14a6653565cede5ad9d43e47e71eaf98f58839f..05379d0a4a5c5312896f8cc13e286ebb37c517e7 100755 (executable)
--- a/t/t3700-add.sh
+++ b/t/t3700-add.sh
@@ -332,4 +332,9 @@ test_expect_success 'git add --dry-run --ignore-missing of non-existing file out
        test_i18ncmp expect.err actual.err
 '
 
+test_expect_success 'git add empty string should invoke warning' '
+       git add "" 2>output &&
+       test_i18ngrep "warning: empty strings" output
+'
+
 test_done