fix(video): pick fal settings from the active start frame input

The Reference Image is a basic upload / advanced reference pair, and the
serializer sends only the active member. The fal settings fields counted
a file left in the inactive member too, so switching to an empty
advanced input kept showing the start frame endpoint's settings while
the run called the prompt endpoint. Resolve the active member with
`resolveActiveCanonicalValue`, and pass `__canonicalModes` to dropdown
option functions as the editor already does for conditions, so a field's
visibility and its options agree.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: myxamediyar

apps/sim/app/workspace/[workspaceId]/w/[workflowId]/components/panel/components/editor/components/sub-block/components/dropdown/dropdown.tsx

@@ -164,15 +164,19 @@ export const Dropdown = memo(function Dropdown({
   }, [multiSelect, value])
 
   // Derived option lists read the block's own values (a model's valid reasoning efforts);
-  // `dependsOn` already re-renders this control when one of those siblings changes.
+  // `dependsOn` already re-renders this control when one of those siblings changes. They also get
+  // `__canonicalModes`, as conditions do, so both read the same active member of a canonical pair.
   const activeWorkflowId = useWorkflowRegistry((state) => state.activeWorkflowId)
   const blockValues = useSubBlockStore((state) =>
     activeWorkflowId ? state.workflowValues[activeWorkflowId]?.[blockId] : undefined
   )
   const evaluatedOptions = useMemo(() => {
-    if (typeof options === 'function') return options({ values: blockValues ?? {} })
-    return options ?? EMPTY_OPTIONS
-  }, [options, blockValues])
+    if (typeof options !== 'function') return options ?? EMPTY_OPTIONS
+    const values = blockValues ?? {}
+    return options({
+      values: canonicalModes ? { ...values, __canonicalModes: canonicalModes } : values,
+    })
+  }, [options, blockValues, canonicalModes])
 
   const reactiveOptions = useMemo(
     () =>

apps/sim/blocks/blocks/video_generator.test.ts

@@ -0,0 +1,41 @@
+import { describe, expect, it } from 'vitest'
+import { evaluateSubBlockCondition } from '@/lib/workflows/subblocks/visibility'
+import { VideoGeneratorV3Block } from '@/blocks/blocks/video_generator'
+
+const frame = { id: 'f', name: 'frame.png', url: '', size: 3, type: 'image/png', key: 'k' }
+
+function aspectRatioField() {
+  const field = VideoGeneratorV3Block.subBlocks.find((subBlock) => subBlock.id === 'falAspectRatio')
+  if (!field) throw new Error('Video Generator must expose a fal aspect ratio field')
+  return field
+}
+
+function optionIds(values: Record<string, unknown>) {
+  const { options } = aspectRatioField()
+  if (typeof options !== 'function') throw new Error('Fal aspect ratio options must be derived')
+  return options({ values }).map((option) => (typeof option === 'string' ? option : option.id))
+}
+
+describe('Video Generator fal start frame', () => {
+  // Happy Horse takes an aspect ratio from a prompt but not from a start frame.
+  const base = { provider: 'falai', model: 'alibaba/happy-horse/text-to-video' }
+
+  it('reads the prompt endpoint when the stored upload is in the inactive mode', () => {
+    const values = {
+      ...base,
+      visualReferenceUpload: frame,
+      visualReferenceInput: '',
+      __canonicalModes: { visualReference: 'advanced' },
+    }
+
+    expect(evaluateSubBlockCondition(aspectRatioField().condition, values)).toBe(true)
+    expect(optionIds(values)).toContain('16:9')
+  })
+
+  it('reads the start frame endpoint when the upload is the active mode', () => {
+    const values = { ...base, visualReferenceUpload: frame }
+
+    expect(evaluateSubBlockCondition(aspectRatioField().condition, values)).toBe(false)
+    expect(optionIds(values)).not.toContain('16:9')
+  })
+})

apps/sim/blocks/blocks/video_generator.ts

@@ -1,3 +1,4 @@
+import { isRecordLike } from '@sim/utils/object'
 import { VideoIcon } from '@/components/icons'
 import {
   directVideoDefaults,
@@ -10,6 +11,11 @@ import {
   getFalVideoModel,
   getFalVideoVariant,
 } from '@/lib/media/fal-video-catalog'
+import {
+  type CanonicalGroup,
+  type CanonicalModeOverrides,
+  resolveActiveCanonicalValue,
+} from '@/lib/workflows/subblocks/visibility'
 import { AuthMode, type BlockConfig, IntegrationType, type SubBlockConfig } from '@/blocks/types'
 import { normalizeFileInput, parseOptionalBooleanInput } from '@/blocks/utils'
 
@@ -52,12 +58,24 @@ const endpointModels = falVideoModels.filter((model) => !model.legacyId)
 const START_FRAME_FIELDS = ['visualReferenceInput', 'visualReferenceUpload']
 const HIDDEN = { field: 'provider', value: [] }
 
+const START_FRAME_GROUP: CanonicalGroup = {
+  canonicalId: 'visualReference',
+  basicId: 'visualReferenceUpload',
+  advancedIds: ['visualReferenceInput'],
+}
+
+/**
+ * Whether the run will send a start frame: the serialized `visualReference`, or else only the
+ * upload/reference member in the active mode, since the serializer drops the inactive one.
+ */
 function hasStartFrame(values?: Record<string, unknown>) {
-  return [
-    values?.visualReference,
-    values?.visualReferenceInput,
-    values?.visualReferenceUpload,
-  ].some((reference) => (Array.isArray(reference) ? reference.length > 0 : Boolean(reference)))
+  if (!values) return false
+  const overrides = isRecordLike(values.__canonicalModes)
+    ? (values.__canonicalModes as CanonicalModeOverrides)
+    : undefined
+  const reference =
+    values.visualReference ?? resolveActiveCanonicalValue(START_FRAME_GROUP, values, overrides)
+  return Array.isArray(reference) ? reference.length > 0 : Boolean(reference)
 }
 
 /** Settings of the endpoint a fal run will call: image-to-video once a start frame is attached. */