51 lines
2.7 KiB
Markdown
51 lines
2.7 KiB
Markdown
# Cremote Daemon Crash - Rod Library Nil Map Panic
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## Error Summary
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The daemon crashed with a panic: `assignment to entry in nil map` in the rod library's `setHelper` function.
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## Root Cause
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This is a known issue in the go-rod library (see https://github.com/go-rod/rod/issues/331).
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When pages are retrieved using `browser.Pages()`, the returned `*rod.Page` objects are not fully initialized. Specifically, internal maps (like the helper map used for JavaScript evaluation) are nil. When methods like `WaitLoad()` try to use these pages, they attempt to write to nil maps, causing a panic.
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This typically happens when:
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1. The daemon is restarted but the browser is still running with existing tabs
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2. A tab is created outside of the daemon
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3. A tab was removed from the cache but still exists in the browser
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## Stack Trace
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```
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headlesschromium | panic: assignment to entry in nil map
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headlesschromium |
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headlesschromium | goroutine 466 [running]:
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headlesschromium | github.com/go-rod/rod.(*Page).setHelper(0x95fc61?, {0xc000156888?, 0x935bc0?}, {0x9553a2, 0x8}, {0xc0003aa1b0, 0x17})
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headlesschromium | /root/go/pkg/mod/github.com/go-rod/rod@v0.116.2/page_eval.go:320 +0xdf
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headlesschromium | github.com/go-rod/rod.(*Page).ensureJSHelper(0xc00013e2c0, 0xf70e80)
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headlesschromium | /root/go/pkg/mod/github.com/go-rod/rod@v0.116.2/page_eval.go:292 +0x47c
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headlesschromium | github.com/go-rod/rod.(*Page).WaitLoad(0xc00013e2c0)
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headlesschromium | /root/go/pkg/mod/github.com/go-rod/rod@v0.116.2/page.go:858 +0x1a5
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headlesschromium | git.teamworkapps.com/shortcut/cremote/daemon.(*Daemon).loadURL.func1()
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headlesschromium | /tmp/cremote/daemon/daemon.go:2532 +0x9d
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```
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## Fix Applied
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Modified `daemon/daemon.go` in the `findPageByID` function to:
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1. **Initialize pages properly**: Call `p.Info()` on pages retrieved from `browser.Pages()` to ensure internal state is initialized
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2. **Add error handling**: Return an error if initialization fails instead of trying to use an uninitialized page
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3. **Add panic recovery**: Use defer/recover to catch any panics during initialization
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4. **Improve caching**: When a page is found and cached, also set up console logging for it
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5. **Add debug logging**: Log when pages are found and cached from the browser
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## Code Changes
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See `daemon/daemon.go` lines 2363-2400 and 2428-2448.
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## Testing
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The code compiles successfully. The fix should prevent the panic by ensuring pages are properly initialized before use.
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## Prevention
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To avoid this issue in the future:
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- Always create tabs through the daemon's `openTab` function
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- Avoid manually creating tabs in the browser when the daemon is running
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- If the daemon is restarted, consider closing all existing browser tabs first
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