CefSettings: RemoteDebuggingPort and/or CefCommandLineArgs stopped working in 126

[SiMoStro]

Is there an existing issue for this?

• I have searched both open/closed issues, no issue already exists.

CefSharp Version

126.2.160

Operating System

Windows 11

Architecture

x64

.Net Version

4.7.2

Implementation

WinForms

Reproduction Steps

We've successfully used the Chromium devtools/debugging feature in all latest versions, initializing CefSettings in this way:

CefSettings settings = new CefSettings
{
    LogSeverity = LogSeverity.Default,
};
settings.RemoteDebuggingPort = 3333;
settings.CefCommandLineArgs.Add("--remote-allow-origins", "*");

starting from version 126.2.70 this has stopped working.
We are currently testing 126.2.180 but the problem persists.

Expected behavior

The Chromium debug console should be available at the configured port:

Actual behavior

The page at the configured port does not generate errors but shows nothing:

Regression?

Yes, this used to work in previus versions.
Note that this problem has been already notified in this thread:

chromiumembedded/cef#3740

but has been closed as "WontFix", but this is clearly a regression.

Known Workarounds

No workaround

Does this problem also occur in the CEF Sample Application

Not Tested

Other information

Other users have already notified the problem:

chromiumembedded/cef#3740

[SiMoStro]

Hi guys,

I don't get why this is now a "discussion" - anyway, attached the solutions which reproduce the bug:

• one links CefSharp 125.0.210 (and CEF 125.0.21)
• the second links CefSharp 126.2.180 (and CEF 126.2.18)

the second one doesn't show the DevTools page.

CefTest_125.zip

CefTest_126.zip

v125

v126

[amaitland]

I don't get why this is now a "discussion" - anyway,

This is an upstream issue and needs to be fixed in CEF. You are welcome to discussion possible workarounds here. It's not a bug in CefSharp.

The short term workaround is revert to using the alloy bootstrap.

#4835 (comment)

Note that this problem has been already notified in this thread:

chromiumembedded/cef#3740

but has been closed as "WontFix", but this is clearly a regression.

This isn't something that can be fixed in CefSharp. If the CEF maintainer has marked as WONTFIX then it will need someone else to debug and submit a PR.

Does this problem also occur in the CEF Sample Application
Not Tested

The problem reproduces with the CEF Sample Application. In future please perform this testing.

[amaitland]

# Works
.\cefclient.exe --use-alloy-style --remote-debugging-port=9955 --disable-request-handling-for-testing --disable-chrome-runtime --remote-allow-origins=http://localhost:9955

# Doesn't work
.\cefclient.exe --use-alloy-style --remote-debugging-port=9955 --disable-request-handling-for-testing  --remote-allow-origins=http://localhost:9955