fix(workspace-forking): keep an unset custom-block boolean unset

Boolean handling collapsed a tri-state. `''` is a flag the user never touched, and
it is not `false`.

On apply, any non-`'true'` string became `false` — so an untouched optional flag
was written as one. `assembleCustomBlockInputMapping` skips `''` but keeps
`false`, so that value reached the child's `inputMapping` and overrode whatever
default the Start field declares. Only an explicit `'true'`/`'false'` is applied
now; anything else leaves the field unset, and the child's own default stands.

In the modal the switch mapped `''` to the False segment, so a required flag
rendered as configured while the Sync gate still read it as empty — the same
display-versus-gate split the previous commit moved into `effectiveDependentValue`
to close, reintroduced one layer up. The value is passed through unmapped instead:
`''` matches neither segment, so the switch renders with nothing selected, which
is what it is.

Reported by Greptile and Cursor Bugbot on #6871.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

Author: icecrasher321

apps/sim/ee/workspace-forking/components/fork-sync/fork-sync-view.tsx

@@ -34,9 +34,7 @@ import {
 } from '@/ee/workspace-forking/components/fork-sync/cleared-refs-list'
 import { forkRefKey } from '@/ee/workspace-forking/components/fork-sync/copy-reconciliation'
 import {
-  CUSTOM_BLOCK_BOOLEAN_FALSE,
   CUSTOM_BLOCK_BOOLEAN_OPTIONS,
-  CUSTOM_BLOCK_BOOLEAN_TRUE,
   customBlockInputControl,
 } from '@/ee/workspace-forking/components/fork-sync/custom-block-input-control'
 import { DependentFieldSelector } from '@/ee/workspace-forking/components/fork-sync/dependent-field-selector'
@@ -236,11 +234,11 @@ function DependentSelector({
           <ChipModalField {...shared} type='custom'>
             <ChipSwitch
               options={CUSTOM_BLOCK_BOOLEAN_OPTIONS}
-              value={
-                value === CUSTOM_BLOCK_BOOLEAN_TRUE
-                  ? CUSTOM_BLOCK_BOOLEAN_TRUE
-                  : CUSTOM_BLOCK_BOOLEAN_FALSE
-              }
+              // Passed through unmapped: an unset field is `''`, which matches neither
+              // segment, so the switch renders with nothing selected. Coercing it to False
+              // would show a required flag as configured while the Sync gate still reads it
+              // as empty — the display-versus-gate split this whole carve-out exists to avoid.
+              value={value}
               onChange={setValue}
               aria-label={field.title}
             />

apps/sim/ee/workspace-forking/lib/copy/copy-workflows.test.ts

@@ -687,4 +687,31 @@ describe('copyWorkflowStateIntoTarget custom-block remap', () => {
     // A string field whose value happens to read "true" stays a string.
     expect(subBlocks.text?.value).toBe('true')
   })
+
+  it('leaves an unset boolean unset rather than writing false', async () => {
+    // The modal submits '' for an untouched optional flag. Coercing that to `false` writes a
+    // value the user never chose: `assembleCustomBlockInputMapping` skips '' but keeps
+    // `false`, so it would reach the child's inputMapping and override the Start field's own
+    // default. Only an explicit 'false' means false.
+    mockSaveWorkflowToNormalizedTables.mockResolvedValue({ success: true })
+
+    await copyWorkflowStateIntoTarget({
+      ...baseParams,
+      tx: stubTx(),
+      transformBlockType: (type) => (type === UAT ? PROD : type),
+      dependentOverrides: new Map([
+        [
+          'tgt-blk-cb',
+          new Map([
+            [`${PROD}::boolean::untouched`, ''],
+            [`${PROD}::boolean::explicit-false`, 'false'],
+          ]),
+        ],
+      ]),
+    })
+
+    const subBlocks = writtenBlock().subBlocks ?? {}
+    expect(subBlocks).not.toHaveProperty('untouched')
+    expect(subBlocks['explicit-false']?.value).toBe(false)
+  })
 })

apps/sim/ee/workspace-forking/lib/remap/remap-references.ts

@@ -313,12 +313,19 @@ export function replaceCustomBlockInputs(
     const parsed = parseCustomBlockInputStorageKey(key)
     if (!parsed || parsed.targetType !== targetType) continue
     if (RESERVED_PARAMS.has(parsed.fieldId)) continue
-    // A `boolean` field's sub-block is a `switch`, which the canvas stores as a real boolean.
+    if (parsed.fieldType === 'boolean') {
+      // A `boolean` field's sub-block is a `switch`, which the canvas stores as a real boolean
+      // — but only `'true'`/`'false'` mean anything. An untouched optional flag submits `''`,
+      // and coercing that to `false` would write a value the user never chose:
+      // `assembleCustomBlockInputMapping` skips `''` and keeps `false`, so it would reach the
+      // child's `inputMapping` and override the Start field's own default. Leave it unset.
+      if (value !== 'true' && value !== 'false') continue
+      next[parsed.fieldId] = { value: value === 'true' }
+      continue
+    }
     // Everything else is stored as text: `object`/`array` are authored as JSON and parsed by
     // the executor, and a number rides a `short-input` like it does on the canvas.
-    next[parsed.fieldId] = {
-      value: parsed.fieldType === 'boolean' ? value === 'true' : value,
-    }
+    next[parsed.fieldId] = { value }
   }
   return next
 }