feat: script module mode with CLI sync, preview, and WAC UI improvements

[rubenfiszel]

Summary

This PR introduces script module mode — a foundational feature that allows Windmill scripts to have companion module files, enabling the Workflow-as-Code (WAC) pattern where scripts can reference task modules via taskScript("./helper.ts").

Script Module System

• Scripts can have associated module files in a __mod/ folder, supporting two layouts:
  • Flat layout: my_script.ts + my_script__mod/helper.ts
  • Folder layout: my_script__mod/script.ts + my_script__mod/helper.ts
• Modules are stored as a modules JSONB column on the script table
• Backend executors (Bun, Python) write module files to the job directory for execution
• Modules are included in script hashing, cloning, workspace export/import

CLI: Sync Pull/Push

• readModulesFromDisk() / writeModulesToDisk() handle reading/writing module files from __mod/ folders
• Fix pull→push idempotency: lock: lock ?? undefined preserves empty strings (API returns lock: "" for modules without deps)
• Module files are pushed/pulled alongside their parent script
• handleScriptMetadata() detects folder layout via isModuleEntryPoint()

CLI: Per-Module Hash Tracking

• Each module gets its own hash entry in wmill-lock.yaml (following the flow inline script pattern)
• SCRIPT_TOP_HASH meta-hash combines main script hash + sorted module hashes
• computeModuleHashes() walks the __mod/ folder and hashes each module's content + workspace deps
• updateModuleLocks() accepts optional changedModules parameter for selective lock regeneration
• Stale detection output shows which specific modules changed: f/test/my_script (bun) [changed modules: helper.ts]

CLI: Preview with Modules

• wmill script preview reads modules from __mod/ and passes them in the runScriptPreviewAndWaitResult API call
• Supports both flat and folder layouts

CLI: Unified generate-metadata

• Module helper files are filtered out (isScriptModulePath && !isModuleEntryPoint) so they're not treated as standalone scripts
• Module changes are detected per-module, not all-or-nothing

Backend: auto_kind Refactor

• Renamed no_main_func: bool → auto_kind: VARCHAR(20) on the script table
• Values: NULL (normal script), "lib" (library/no main), "wac" (workflow-as-code)
• Parser detects WAC scripts by analyzing workflow() + task() patterns in TypeScript and Python
• Migration converts existing no_main_func = true rows to auto_kind = 'lib'

Backend: WAC v2 Execution

• Bun executor generates a WAC v2 wrapper that imports WorkflowCtx, StepSuspend, setWorkflowCtx from windmill-client
• Wrapper handles checkpoint/replay semantics: complete, dispatch, sleep, approval modes
• Python executor supports WAC via wmill.workflow() / wmill.task() decorators

Frontend: WAC UI

• WAC TypeScript/Python templates with task(), taskScript(), step(), sleep(), waitForApproval()
• TypeScript templates shown before Python in all template selectors
• Module tab system in ScriptEditor: add, rename (pencil icon popover on hover), delete modules
• Fixed-width icon container (w-[32px]) prevents layout shift on hover
• Simplified +Script button (removed dropdown), consolidated WAC actions under +Flow dropdown
• "Import Workflow-as-Code" drawer for importing WAC scripts from YAML/JSON
• WAC export drawer for exporting scripts as YAML

Key Files Changed

Area	Files	Changes
Backend types	windmill-types/src/scripts.rs	auto_kind field, ScriptModule struct, hash impl
Backend API	windmill-api-scripts/src/scripts.rs	auto_kind in create/update
Backend workers	bun_executor.rs, python_executor.rs, worker.rs	Module file writing, WAC v2 wrapper
Backend parsers	windmill-parser-ts, windmill-parser-py	WAC detection
Backend migration	20260313000000_script_auto_kind.up.sql	Column rename
CLI script	cli/src/commands/script/script.ts	readModulesFromDisk, preview, push/pull
CLI metadata	cli/src/utils/metadata.ts	Hash tracking, selective lock regen
CLI generate-metadata	cli/src/commands/generate-metadata/	Module filtering
Frontend editor	ScriptEditor.svelte	Module tabs, rename popover
Frontend builder	ScriptBuilder.svelte	WAC templates, ordering
Frontend actions	CreateActionsFlow.svelte, CreateActionsScript.svelte	WAC import/dropdown

Test plan

• bun test test/script_modules.test.ts — module sync unit tests
• bun test test/resource_folders_unit.test.ts — path utility tests
• bun test test/unified_generate_metadata.test.ts — metadata generation including module modification detection
• bun test test/sync_pull_push.test.ts — sync round-trip tests
• bun test test/preview.test.ts — preview with modules (flat + folder layout)
• cargo check --features zip with -D warnings — clean compilation
• svelte-check — 0 errors in changed files
• Manual: wmill sync pull → wmill sync push produces 0 changes for scripts with modules
• Manual: Change one module → wmill generate-metadata only regenerates that module's lock
• Manual: wmill script preview works with WAC scripts that have modules
• Manual: Module tab rename popover in ScriptEditor

🤖 Generated with Claude Code

[cloudflare-workers-and-pages]

Deploying windmill with    Cloudflare Pages

Latest commit:	a4cb9c9
Status:	✅  Deploy successful!
Preview URL:	https://824e3bce.windmill.pages.dev
Branch Preview URL:	https://module-mode.windmill.pages.dev

View logs