fixes

acceptance/bundle/variables/double_underscore/output.txt

@@ -1,9 +1,7 @@
 
->>> $CLI bundle validate
-Name: double_underscore
-Target: default
-Workspace:
-  User: $USERNAME
-  Path: /Workspace/Users/$USERNAME/.bundle/double_underscore/default
-
-Validation OK!
+>>> $CLI bundle validate -o json
+[
+  {
+    "task_key": "test default"
+  }
+]

acceptance/bundle/variables/double_underscore/script

@@ -1 +1 @@
-trace $CLI bundle validate
+trace $CLI bundle validate -o json | jq .resources.jobs.test_job.tasks

libs/dyn/dynvar/ref.go

@@ -1,13 +1,16 @@
 package dynvar
 
 import (
+	"fmt"
 	"regexp"
-	"strings"
 
 	"github.com/databricks/cli/libs/dyn"
 )
 
-var re = regexp.MustCompile(`\$\{([a-zA-Z]+([-_]*[a-zA-Z0-9]+)*(\.[a-zA-Z]+([-_]*[a-zA-Z0-9]+)*(\[[0-9]+\])*)*(\[[0-9]+\])*)\}`)
+var (
+	baseVarDef = `[a-zA-Z]+([-_]*[a-zA-Z0-9]+)*`
+	re         = regexp.MustCompile(fmt.Sprintf(`\$\{(%s(\.%s(\[[0-9]+\])*)*(\[[0-9]+\])*)\}`, baseVarDef, baseVarDef))
+)
 
 // ref represents a variable reference.
 // It is a string [dyn.Value] contained in a larger [dyn.Value].
@@ -23,8 +26,6 @@ type ref struct {
 	matches [][]string
 }
 
-var invalidSeq = []string{"-_", "_-"}
-
 // newRef returns a new ref if the given [dyn.Value] contains a string
 // with one or more variable references. It returns false if the given
 // [dyn.Value] does not contain variable references.
@@ -45,16 +46,6 @@ func newRef(v dyn.Value) (ref, bool) {
 		return ref{}, false
 	}
 
-	// Check that it does not have invalid sequences such as "-_" or "_-".
-
-	for _, match := range m {
-		for _, seq := range invalidSeq {
-			if strings.Contains(match[1], seq) {
-				return ref{}, false
-			}
-		}
-	}
-
 	return ref{
 		value:   v,
 		str:     s,

libs/dyn/dynvar/ref_test.go

@@ -20,6 +20,8 @@ func TestNewRefValidPattern(t *testing.T) {
 		"${hello-world.world-world}":  {"hello-world.world-world"},
 		"${hello_world.world__world}": {"hello_world.world__world"},
 		"${hello_world.world--world}": {"hello_world.world--world"},
+		"${hello_world.world-_world}": {"hello_world.world-_world"},
+		"${hello_world.world_-world}": {"hello_world.world_-world"},
 	} {
 		ref, ok := newRef(dyn.V(in))
 		require.True(t, ok, "should match valid pattern: %s", in)
@@ -38,7 +40,6 @@ func TestNewRefInvalidPattern(t *testing.T) {
 		"${_-_._-_.id}",                 // cannot use _- in sequence
 		"${0helloworld.world-world}",    // interpolated first section shouldn't start with number
 		"${helloworld.9world-world}",    // interpolated second section shouldn't start with number
-		"${a-a.a-_a-a.id}",              // fails because of -_ in the second segment
 	}
 	for _, v := range invalid {
 		_, ok := newRef(dyn.V(v))