[PATCH v6 3/7] scalar: validate the optional enlistment argument

["Johannes Schindelin via GitGitGadget" <gitgitgadget@gmail.com>]

From: Johannes Schindelin <johannes.schindelin@gmx.de>

The `scalar` command needs a Scalar enlistment for many subcommands, and
looks in the current directory for such an enlistment (traversing the
parent directories until it finds one).

These is subcommands can also be called with an optional argument
specifying the enlistment. Here, too, we traverse parent directories as
needed, until we find an enlistment.

However, if the specified directory does not even exist, or is not a
directory, we should stop right there, with an error message.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 contrib/scalar/scalar.c          | 6 ++++--
 contrib/scalar/t/t9099-scalar.sh | 5 +++++
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/contrib/scalar/scalar.c b/contrib/scalar/scalar.c
index 1ce9c2b00e8..00dcd4b50ef 100644
--- a/contrib/scalar/scalar.c
+++ b/contrib/scalar/scalar.c
@@ -43,9 +43,11 @@ static void setup_enlistment_directory(int argc, const char **argv,
 		usage_with_options(usagestr, options);
 
 	/* find the worktree, determine its corresponding root */
-	if (argc == 1)
+	if (argc == 1) {
 		strbuf_add_absolute_path(&path, argv[0]);
-	else if (strbuf_getcwd(&path) < 0)
+		if (!is_directory(path.buf))
+			die(_("'%s' does not exist"), path.buf);
+	} else if (strbuf_getcwd(&path) < 0)
 		die(_("need a working directory"));
 
 	strbuf_trim_trailing_dir_sep(&path);
diff --git a/contrib/scalar/t/t9099-scalar.sh b/contrib/scalar/t/t9099-scalar.sh
index 2e1502ad45e..9d83fdf25e8 100755
--- a/contrib/scalar/t/t9099-scalar.sh
+++ b/contrib/scalar/t/t9099-scalar.sh
@@ -85,4 +85,9 @@ test_expect_success 'scalar delete with enlistment' '
 	test_path_is_missing cloned
 '
 
+test_expect_success '`scalar [...] <dir>` errors out when dir is missing' '
+	! scalar run config cloned 2>err &&
+	grep "cloned. does not exist" err
+'
+
 test_done
-- 
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