fix(linux): resolve startup hang caused by Webview log target deadlock by MareDevi · Pull Request #150 · dannysmith/astro-editor

MareDevi · 2026-03-10T11:06:26Z

Problem

On Linux (tested on Arch Linux with Wayland + WebKitGTK), running pnpm run tauri dev hangs permanently after:

[INFO] Astro Editor v1.0.10 starting up
[mio::poll][TRACE] registering event source with poller: token=Token(1), interests=READABLE

The app window never appears. The same hang occurs with cargo run directly.

Root Cause

Two separate issues, both Linux-specific:

1. `tauri_plugin_log` Webview target deadlock (`lib.rs`)

The Webview log target calls app.emit() internally on every log::info! call. During setup(), the WebKitGTK webview process does not yet exist. On Linux, this causes the underlying IPC socket to be registered with mio (Token(1), interests=READABLE) with no peer to write to it — the epoll event never fires and setup() blocks forever.

This was confirmed by bisecting with eprintln! checkpoints: execution stops inside the first log::info! call and never returns.

On macOS the webview initialisation order is different and this path is safe.

2. `macos-private-api` in base `[dependencies]` (`Cargo.toml`)

tauri-build validates that the macos-private-api Cargo feature matches "macOSPrivateApi": true in the merged tauri.conf.json. On macOS, tauri.macos.conf.json is merged in at build time and supplies that key. On Linux only tauri.conf.json + tauri.linux.conf.json are merged — neither contains macOSPrivateApi — so the build fails with:

The `tauri` dependency features on the `Cargo.toml` file does not match the allowlist defined under `tauri.conf.json`.

The existing comment states this feature is "a no-op on non-macOS", but tauri-build's validation fires regardless of platform.

Fix

src-tauri/src/lib.rs — restrict the Webview log target to macOS only using #[cfg(target_os = "macos")]. Stdout and LogDir targets continue to work on all platforms.

src-tauri/Cargo.toml — move macos-private-api from the base [dependencies] into [target.'cfg(target_os = "macos")'.dependencies]. Cargo merges features across sections, so macOS builds retain the full feature set (protocol-asset + macos-private-api) while Linux/Windows builds only get protocol-asset, satisfying tauri-build on both platforms.

Testing

Verified on Arch Linux (Wayland, WebKitGTK 4.1 + 6.0). The app now starts up fully and the window appears. cargo clippy and cargo fmt --check pass cleanly.

Summary by CodeRabbit

Chores
- Moved macOS-specific dependency entries into a platform-only configuration to tidy build settings.
- Adjusted logging setup to include a macOS-only log target while keeping cross-platform outputs.
- Result: clearer macOS build behavior and improved macOS diagnostics without affecting other platforms.

On Linux/Windows, tauri_plugin_log's Webview target deadlocks on the first log::info! call inside setup(). The WebKitGTK IPC socket is registered with mio (token=Token(1), interests=READABLE) before the webview process exists, so the epoll event never fires and setup() blocks forever - the app window never appears. Fix by restricting the Webview log target to macOS only via #[cfg(target_os = "macos")], where initialisation order is safe. Stdout and LogDir targets are unaffected on all platforms. Also fix Cargo.toml: macos-private-api cannot be in the base [dependencies] on Linux because tauri-build validates that the feature matches "macOSPrivateApi": true in the merged tauri.conf.json. That key only exists in tauri.macos.conf.json, which is merged at build time on macOS only. Move macos-private-api to [target.'cfg(target_os = "macos")'.dependencies] so Cargo merges the feature on macOS while Linux builds omit it cleanly.

coderabbitai · 2026-03-10T11:06:46Z

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Reviewing files that changed from the base of the PR and between ef58d0c and 45285d5.

📒 Files selected for processing (1)

src-tauri/src/lib.rs

🚧 Files skipped from review as they are similar to previous changes (1)

src-tauri/src/lib.rs

📝 Walkthrough

Walkthrough

Reorganizes tauri dependency: moves macos-private-api feature into a macOS-specific target dependency in src-tauri/Cargo.toml. Refactors logging setup in src-tauri/src/lib.rs to build a targets vector conditionally including a Webview target on non-Linux macOS/Linux builds.

Changes

Cohort / File(s)	Summary
Tauri dependency config `src-tauri/Cargo.toml`	Moves `macos-private-api` feature out of the base `[dependencies]` and into a `cfg(target_os = "macos")` target-specific `tauri` entry.
Logging plugin configuration `src-tauri/src/lib.rs`	Replaces inline `tauri_plugin_log::Builder` targets array with a closure that constructs a `targets` vector and conditionally adds a Webview target (excluded on Linux), then builds the `Builder` from that vector.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~12 minutes

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Moving features where they ought to go,
Logs assemble, platforms sing along,
Tiny refactors—swift and strong! 🐇✨

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Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately describes the main change: fixing a Linux startup hang caused by the Webview log target deadlock.
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Copilot

Pull request overview

Fixes a Linux-only startup hang in the Tauri app by avoiding an early Webview log target path that can deadlock during setup(), and adjusts Cargo feature configuration so tauri-build validation passes on non-macOS platforms.

Changes:

Conditionally include tauri_plugin_log::TargetKind::Webview only for macOS.
Move tauri’s macos-private-api feature into a macOS-only dependency section, keeping protocol-asset in the base dependency.

Reviewed changes

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

File	Description
`src-tauri/src/lib.rs`	Makes the log plugin targets platform-conditional to avoid Linux startup deadlock.
`src-tauri/Cargo.toml`	Splits `tauri` features by platform to satisfy `tauri-build` feature/allowlist validation.

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src-tauri/src/lib.rs

Co-authored-by: Copilot <[email protected]>

dannysmith · 2026-03-12T03:06:11Z

@MareDevi Thanks for this. Gimme a few days to review and merge.

dannysmith · 2026-03-12T03:43:48Z

@MareDevi Just realised this is like a 15-line diff 😅 Looks good - thanks 🙂

On Linux with WebKitGTK, the Webview log target causes app.emit() to deadlock during setup() because the webview process doesn't exist yet. The IPC socket registers with epoll but never receives a response, blocking forever on the first log::info!() call. Guard the Webview target with #[cfg(not(target_os = "linux"))]. Stdout and LogDir targets continue to work on all platforms. Ref: dannysmith/astro-editor#150 Co-Authored-By: Claude Opus 4.6 (1M context) <[email protected]>

Copilot AI review requested due to automatic review settings March 10, 2026 11:06

Copilot started reviewing on behalf of MareDevi March 10, 2026 11:07 View session

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src-tauri/src/lib.rs Outdated Show resolved Hide resolved

MareDevi mentioned this pull request Mar 10, 2026

Question: Linux Support #137

Closed

Update src-tauri/src/lib.rs

45285d5

Co-authored-by: Copilot <[email protected]>

MareDevi mentioned this pull request Mar 11, 2026

feat: add live preview panel with dev server integration #152

Closed

dannysmith merged commit a1380de into dannysmith:main Mar 12, 2026
4 checks passed

dannysmith mentioned this pull request Mar 17, 2026

fix: correctly handle and preserve full timestamp precision for blog … #158

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fix(linux): resolve startup hang caused by Webview log target deadlock#150

fix(linux): resolve startup hang caused by Webview log target deadlock#150
dannysmith merged 2 commits intodannysmith:mainfrom
MareDevi:fix/linux-startup-hang

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MareDevi commented Mar 10, 2026 • edited by coderabbitai bot Loading Uh oh! There was an error while loading. Please reload this page.

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Problem

Root Cause

1. tauri_plugin_log Webview target deadlock (lib.rs)

2. macos-private-api in base [dependencies] (Cargo.toml)

Fix

Testing

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MareDevi commented Mar 10, 2026 •

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1. `tauri_plugin_log` Webview target deadlock (`lib.rs`)

2. `macos-private-api` in base `[dependencies]` (`Cargo.toml`)

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