[leaanthony]

Description

darwin:build:universal declares its amd64/arm64 builds as task deps, which go-task runs in parallel. Each arch build's chain includes common:build:frontend → generate:bindings -clean=true, so one universal build executed the entire frontend pipeline twice concurrently: one invocation deletes/regenerates frontend/bindings while the other's bundler reads it. On slow CI runners the bundler loses the race and fails with the reported Could not resolve \"./bindings/changeme\". Two concurrent go mod tidy processes also race on go.mod.

Fix

Mark the shared, arch-independent tasks as run: once: go:mod:tidy, install:frontend:deps, build:frontend, generate:bindings, generate:icons. Concurrent invocations with identical vars now deduplicate — the second waits for the first instead of re-running. Per-arch Go builds remain fully parallel.

Side benefit: universal builds run the frontend pipeline once instead of twice.

Verification (proves the issue)

Scaffolded one app from the master CLI and one from this branch, ran darwin:build:universal on macOS, counted executions in the task output:

Template	wails3 generate bindings runs	frontend bundles	result
master	2 (concurrent)	2	binary OK locally (fast machine — CI loses the timing)
this branch	1	1	lipo -archs → x86_64 arm64 ✓

The reporter's CI logs show the same double-execution interleaving before the rollup failure.

Existing projects pick the fix up via wails3 update build-assets (noted in the changelog).

Fixes #4637

Type of change

• Bug fix (non-breaking change which fixes an issue)

Checklist:

• My code follows the general coding style of this project
• I have updated v3/UNRELEASED_CHANGELOG.md

Summary by CodeRabbit

• Bug Fixes
  • Prevented intermittent failures in universal macOS builds by ensuring shared build tasks run only once, eliminating race conditions during parallel per-architecture builds.
  • Existing projects can apply the fix by updating build assets.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: 189f0f13-808b-484c-829e-5194710fcb68

📥 Commits

Reviewing files that changed from the base of the PR and between d31e109 and ad02b72.

📒 Files selected for processing (1)

• v3/UNRELEASED_CHANGELOG.md

✅ Files skipped from review due to trivial changes (1)

• v3/UNRELEASED_CHANGELOG.md

---

Walkthrough

Adds run: once to five shared Taskfile tasks to serialize execution across parallel per-architecture builds, preventing concurrent regeneration/cleanup races that caused intermittent binding resolution failures; updates the Unreleased changelog to document the fix and the update path for existing projects.

Changes

Build Task Serialization for Parallel Architecture Safety

Layer / File(s)	Summary
Build task serialization guards v3/internal/commands/build_assets/Taskfile.tmpl.yml, v3/UNRELEASED_CHANGELOG.md	Adds run: once to go:mod:tidy (with comment about go.mod corruption), install:frontend:deps, build:frontend (notes universal per-arch parallelism), generate:bindings, and generate:icons; updates changelog entry and references wails3 update build-assets for existing projects.

Possibly related PRs

• wailsapp/wails#4093: Related to bindings generation and universal/GOARCH handling for GenerateBindings.
• wailsapp/wails#3902: Introduced darwin:build:universal flow that exposes the parallel per-arch build behavior addressed by this change.
• wailsapp/wails#4023: Modifies Taskfile frontend/bindings tasks; related at the build-assets task level.

Suggested labels: v3-alpha

🐰 When arches race in parallel dreams,
Bindings clash in concurrent streams.
run: once whispers, "Only I will run,"
One generation done — now builds flow on. ✨

🎯 2 (Simple) | ⏱️ ~10 minutes

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and specifically summarizes the main change: preventing shared tasks from racing during parallel universal builds by deduplicating them.
Description check	✅ Passed	The description provides thorough context, explains the root cause, details the fix, includes verification results, and completes the required checklist items.
Linked Issues check	✅ Passed	The code changes directly address issue #4637 by implementing the fix to prevent concurrent execution of shared tasks (go:mod:tidy, install:frontend:deps, build:frontend, generate:bindings, generate:icons) during parallel universal builds.
Out of Scope Changes check	✅ Passed	All changes are directly scoped to fixing the universal build race condition: updating the changelog and adding run:once constraints to five specific shared tasks.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/universal-build-race-4637

---

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[Copilot]

Pull request overview

This PR fixes an intermittent CI failure in v3 darwin:build:universal where per-arch builds run as parallel dependencies and were concurrently re-running shared frontend/build-asset tasks (notably bindings generation with -clean=true), causing the frontend bundler to sometimes read a partially-deleted frontend/bindings directory.

Changes:

• Mark shared, arch-independent Taskfile steps as run: once so parallel universal-build deps dedupe instead of executing concurrently (go:mod:tidy, install:frontend:deps, build:frontend, generate:bindings, generate:icons).
• Add a changelog entry documenting the universal build race fix and the recommended update path for existing projects.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
v3/internal/commands/build_assets/Taskfile.tmpl.yml	Adds run: once to shared tasks to prevent concurrent duplicate execution during parallel multi-arch builds.
v3/UNRELEASED_CHANGELOG.md	Documents the intermittent universal-build bindings resolution failure fix and mitigation.

---

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[coderabbitai]

🧹 Nitpick comments (1)

v3/internal/commands/build_assets/Taskfile.tmpl.yml (1)

15-15: 💤 Low value

Consider adding explanatory comments for consistency.

Three tasks (install:frontend:deps, generate:bindings, generate:icons) gained run: once without explanatory comments, while go:mod:tidy and build:frontend include detailed race-condition explanations. Adding brief comments to the remaining tasks would help future maintainers understand why the directive is necessary and maintain consistency with the documented tasks.

📝 Suggested comment additions

For install:frontend:deps (after line 14):

   install:frontend:deps:
     summary: Install frontend dependencies
+    # Parallel per-arch builds share the same node_modules; concurrent installs race.
     run: once

For generate:bindings (after line 178):

   generate:bindings:
     label: generate:bindings (BUILD_FLAGS={{.Opn}}.BUILD_FLAGS{{.Cls}})
     summary: Generates bindings for the frontend
+    # Parallel builds share frontend/bindings; -clean=true causes one to delete while the other reads.
     run: once

For generate:icons (after line 195):

   generate:icons:
     summary: Generates Windows `.ico` and Mac `.icns` from an image; on macOS, `-iconcomposerinput appicon.icon -macassetdir darwin` also produces `Assets.car` from a `.icon` file (skipped on other platforms).
+    # Parallel builds share build/darwin and build/windows icon outputs.
     run: once

Also applies to: 179-179, 196-196

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@v3/internal/commands/build_assets/Taskfile.tmpl.yml` at line 15, The three
Taskfile tasks install:frontend:deps, generate:bindings, and generate:icons each
set run: once but lack explanatory comments; add a short comment above or
immediately after each task stating why run: once is required (e.g., to avoid
concurrent execution/race conditions and because the step is a one-time or
expensive setup operation), mirroring the style and brevity used in the existing
go:mod:tidy and build:frontend comments so maintainers understand the rationale
for run: once.

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Nitpick comments:
In `@v3/internal/commands/build_assets/Taskfile.tmpl.yml`:
- Line 15: The three Taskfile tasks install:frontend:deps, generate:bindings,
and generate:icons each set run: once but lack explanatory comments; add a short
comment above or immediately after each task stating why run: once is required
(e.g., to avoid concurrent execution/race conditions and because the step is a
one-time or expensive setup operation), mirroring the style and brevity used in
the existing go:mod:tidy and build:frontend comments so maintainers understand
the rationale for run: once.

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: d85786ed-ec6f-492d-a097-63c7758773d6

📥 Commits

Reviewing files that changed from the base of the PR and between 2633f81 and d31e109.

📒 Files selected for processing (2)

• v3/UNRELEASED_CHANGELOG.md
• v3/internal/commands/build_assets/Taskfile.tmpl.yml