2 files changed, 43 insertions, 0 deletions
diff --git a/internal/engine/engine.go b/internal/engine/engine.go
index 00a249d..958e4f9 100644
--- a/internal/engine/engine.go
+++ b/internal/engine/engine.go
@@ -177,6 +177,11 @@ func Load(mainFile string, names ...string) (*Engine, []*config.Diag) {
 func checkCaptures(file string, r *config.Rule, c *cond.Cond) *config.Diag {
 	groups := c.NameGroups()
 	for _, a := range r.Actions {
+		if err := plan.CheckTemplate(a.Arg); err != nil {
+			// A placeholder that could never expand is a config error, not a
+			// step skipped at plan time (plan 12).
+			return &config.Diag{File: file, Pos: a.Pos, Msg: fmt.Sprintf("rule %q: %v", r.Name, err)}
+		}
 		n, err := plan.MaxIndex(a.Arg)
 		if err != nil || n == 0 {
 			continue
diff --git a/internal/engine/engine_test.go b/internal/engine/engine_test.go
index 9de3ea4..4af8f79 100644
--- a/internal/engine/engine_test.go
+++ b/internal/engine/engine_test.go
@@ -256,3 +256,41 @@ func TestLoadAcceptsDuplicateWithMove(t *testing.T) {
 		}
 	}
 }
+
+// TestLoadRefusesBadPlaceholders: a copy or move destination or a rename
+// name whose placeholders could never expand is a config error at load, so
+// krino check reports it at the action's position instead of a run skipping
+// the step (plan 12).
+func TestLoadRefusesBadPlaceholders(t *testing.T) {
+	for _, c := range []struct {
+		action, want string
+	}{
+		{`(move "Out/{foo}")`, "unknown placeholder {foo}"},
+		{`(move "Out/{mtime}")`, "unknown placeholder {mtime}"},
+		{`(move "Out/{now}")`, "unknown placeholder {now}"},
+		{`(move "Out/{mtime:%B}")`, "%B"},
+		{`(rename "{0}-x")`, "numbered from 1"},
+		{`(copy "Out/{10}")`, "unknown placeholder {10}"},
+		{`(move "Out/{name")`, "unclosed placeholder"},
+	} {
+		h := sandbox(t)
+		os.MkdirAll(filepath.Join(h, "dl"), 0o755)
+		main := writeConfig(t, h, `(include "dl")`, map[string]string{"dl": "(path \"~/dl\")\n(rule \"r\" (when (name \"^(a)\")) " + c.action + ")\n"})
+		_, errs := Load(main)
+		found := false
+		for _, e := range errs {
+			if strings.Contains(e.Error(), c.want) && strings.Contains(e.Error(), "dl.conf:2:") {
+				found = true
+			}
+		}
+		if !found {
+			t.Errorf("%s: errors %v; want %q at line 2", c.action, errs, c.want)
+		}
+	}
+	h := sandbox(t)
+	os.MkdirAll(filepath.Join(h, "dl"), 0o755)
+	main := writeConfig(t, h, `(include "dl")`, map[string]string{"dl": "(path \"~/dl\")\n(rule \"r\" (when (name \"^(a)\")) (rename \"{1}-{stem}{ext}\") (move \"Out/{mtime:%Y/%m}/{{x}}/{now:%j}\"))\n"})
+	if _, errs := Load(main); len(errs) > 0 {
+		t.Errorf("valid placeholders refused: %v", errs)
+	}
+}