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crash fix

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This commit is contained in:
Josh at WLTechBlog
2025-12-24 11:00:37 -07:00
parent 6f9839ee86
commit f09cdc2973
2 changed files with 77 additions and 38 deletions
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15
daemon/daemon.go
View File

@@ -2596,6 +2596,15 @@ func (d *Daemon) loadURL(tabID, url string, timeout int) error {
}
d.debugLog("Got tab %s, starting navigation", tabID)
// Ensure page is fully initialized before using in goroutine
// This prevents "assignment to entry in nil map" panics in rod library
// See: https://github.com/go-rod/rod/issues/331
_, err = page.Info()
if err != nil {
d.debugLog("Warning: failed to initialize page %s: %v", tabID, err)
// Continue anyway, as the page might still work
}
if timeout > 0 {
// Use timeout for the URL loading
ctx, cancel := context.WithTimeout(context.Background(), time.Duration(timeout)*time.Second)
@@ -2606,6 +2615,12 @@ func (d *Daemon) loadURL(tabID, url string, timeout int) error {
// Execute the navigation in a goroutine
go func() {
defer func() {
if r := recover(); r != nil {
done <- fmt.Errorf("navigation panicked: %v", r)
}
}()
err := page.Navigate(url)
if err != nil {
done <- fmt.Errorf("failed to navigate to URL: %w", err)

100
error.md
View File

@@ -1,50 +1,74 @@
# Cremote Daemon Crash - Rod Library Nil Map Panic
# FIXED: Rod Library Nil Map Panic in loadURL
## Error Summary
The daemon crashed with a panic: `assignment to entry in nil map` in the rod library's `setHelper` function.
## Original Error
```
panic: assignment to entry in nil map
goroutine 78 [running]:
github.com/go-rod/rod.(*Page).setHelper(0x962da8?, {0xc000212258?, 0x938c80?}, {0x9584a2, 0x8}, {0xc000212288, 0x17})
/root/go/pkg/mod/github.com/go-rod/rod@v0.116.2/page_eval.go:320 +0xdf
github.com/go-rod/rod.(*Page).ensureJSHelper(0xc000140210, 0xf76e80)
/root/go/pkg/mod/github.com/go-rod/rod@v0.116.2/page_eval.go:292 +0x47c
github.com/go-rod/rod.(*Page).formatArgs(0xc000140210, 0xc00012eda8?)
/root/go/pkg/mod/github.com/go-rod/rod@v0.116.2/page_eval.go:234 +0x1e5
github.com/go-rod/rod.(*Page).evaluate(0xc000140210, 0xc0000d5f00)
/root/go/pkg/mod/github.com/go-rod/rod@v0.116.2/page_eval.go:150 +0x32
github.com/go-rod/rod.(*Page).Evaluate(0xc000140210, 0xc0000d5f00)
/root/go/pkg/mod/github.com/go-rod/rod@v0.116.2/page_eval.go:129 +0x4a
github.com/go-rod/rod.(*Page).WaitLoad(0xc000140210)
/root/go/pkg/mod/github.com/go-rod/rod@v0.116.2/page.go:858 +0x1a5
git.teamworkapps.com/shortcut/cremote/daemon.(*Daemon).loadURL.func1()
/tmp/cremote/daemon/daemon.go:2616 +0x9d
created by git.teamworkapps.com/shortcut/cremote/daemon.(*Daemon).loadURL in goroutine 74
/tmp/cremote/daemon/daemon.go:2608 +0x345
```
## Root Cause
This is a known issue in the go-rod library (see https://github.com/go-rod/rod/issues/331).
This is a known issue in go-rod v0.116.2 (https://github.com/go-rod/rod/issues/331).
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.
When `page.WaitLoad()` is called in a goroutine, there can be race conditions with the internal helper map initialization. The page's internal maps may not be fully initialized when the goroutine starts executing, causing a nil map panic.
This typically happens when:
1. The daemon is restarted but the browser is still running with existing tabs
2. A tab is created outside of the daemon
3. A tab was removed from the cache but still exists in the browser
## Solution Applied
Modified `daemon/daemon.go` in the `loadURL` function (lines 2589-2629):
## Stack Trace
```
headlesschromium | panic: assignment to entry in nil map
headlesschromium |
headlesschromium | goroutine 466 [running]:
headlesschromium | github.com/go-rod/rod.(*Page).setHelper(0x95fc61?, {0xc000156888?, 0x935bc0?}, {0x9553a2, 0x8}, {0xc0003aa1b0, 0x17})
headlesschromium | /root/go/pkg/mod/github.com/go-rod/rod@v0.116.2/page_eval.go:320 +0xdf
headlesschromium | github.com/go-rod/rod.(*Page).ensureJSHelper(0xc00013e2c0, 0xf70e80)
headlesschromium | /root/go/pkg/mod/github.com/go-rod/rod@v0.116.2/page_eval.go:292 +0x47c
headlesschromium | github.com/go-rod/rod.(*Page).WaitLoad(0xc00013e2c0)
headlesschromium | /root/go/pkg/mod/github.com/go-rod/rod@v0.116.2/page.go:858 +0x1a5
headlesschromium | git.teamworkapps.com/shortcut/cremote/daemon.(*Daemon).loadURL.func1()
headlesschromium | /tmp/cremote/daemon/daemon.go:2532 +0x9d
```
1. **Added page initialization before goroutine** (lines 2597-2603):
- Call `page.Info()` to ensure internal state is initialized
- This prevents the nil map issue by forcing initialization on the main goroutine
## Fix Applied
Modified `daemon/daemon.go` in the `findPageByID` function to:
1. **Initialize pages properly**: Call `p.Info()` on pages retrieved from `browser.Pages()` to ensure internal state is initialized
2. **Add error handling**: Return an error if initialization fails instead of trying to use an uninitialized page
3. **Add panic recovery**: Use defer/recover to catch any panics during initialization
4. **Improve caching**: When a page is found and cached, also set up console logging for it
5. **Add debug logging**: Log when pages are found and cached from the browser
2. **Added panic recovery in goroutine** (lines 2618-2622):
- Added `defer/recover` block to catch any panics
- Returns descriptive error message if panic occurs
- Prevents daemon crash and allows graceful error handling
## Code Changes
See `daemon/daemon.go` lines 2363-2400 and 2428-2448.
```go
// Ensure page is fully initialized before using in goroutine
// This prevents "assignment to entry in nil map" panics in rod library
// See: https://github.com/go-rod/rod/issues/331
_, err = page.Info()
if err != nil {
d.debugLog("Warning: failed to initialize page %s: %v", tabID, err)
// Continue anyway, as the page might still work
}
// Execute the navigation in a goroutine
go func() {
defer func() {
if r := recover(); r != nil {
done <- fmt.Errorf("navigation panicked: %v", r)
}
}()
err := page.Navigate(url)
// ... rest of navigation code
}()
```
## Testing
The code compiles successfully. The fix should prevent the panic by ensuring pages are properly initialized before use.
✅ Code compiles successfully
✅ Panic recovery in place
✅ Page initialization added before goroutine
✅ Consistent with fix in `waitNavigation` function
## Prevention
To avoid this issue in the future:
- Always create tabs through the daemon's `openTab` function
- Avoid manually creating tabs in the browser when the daemon is running
- If the daemon is restarted, consider closing all existing browser tabs first
## Related Fixes
This is similar to the fix previously applied to `findPageByID()` and `waitNavigation()`, but was missing in `loadURL()`.