Browse to the.app file that you want to debug ( Firefox.app, Nightly Debug.app etc). The.app file is typically found inside the dist folder in your build directory.

If you want to debug from the terminal see Debugging Mozilla with lldb.

For specific information on a way to debug hangs, see Debugging a hang on OS X.

Uplifts to Firefox 68 and ESR 68 to enable Notarization are planned.

As a result, it is not possible to attach a debugger to these official Firefox releases on macOS 10.14 without disabling System Integrity Protection (SIP).

This is due to Notarization requiring Hardened Runtime to be enabled with the com.apple.security.get-task-allow entitlement disallowed.

Rather than disabling SIP (which has security implications), it is recommended to debug with try builds or local builds.

These builds enable Hardened Runtime and only differ from production builds in that they are not Notarized which should not otherwise affect functionality, (other than the ability to easily launch the browser on macOS 10.15 -- see quarantine note below).

At this time, developers can obtain a Hardened Runtime build with the com.apple.security.get-task-allow entitlement allowed by submitting a try build and downloading the dmg generated by the Rpk shippable build job.

A debugger can be attached to Firefox processes of these builds.

To workaround this problem, remove the quarantine extended attribute from the downloaded Nightly.

As a result, some functionality will be permitted on local builds, but blocked on production builds which have Hardened Runtime enabled.

Bug 1522409 was filed to automate codesigning local builds to enable Hardened Runtime by default and eliminate this discrepancy.

Note that disabling SIP bypasses Hardened Runtime restrictions which can mask some bugs that only occur with Hardened Runtime so it is recommended to test fixes with SIP enabled.

Disabling SIP has system security implications that should be understood before taking this step.

To work around that, the steps below have you initialize the project outside the Mozilla source tree, close the project, copy the.xcodeproj project file into the source tree, and then reopen the project to finish setting it up.

If you try to do that then Xcode will simply copy the source files under the project directory rather than link to them (still the case in Xcode 10) which breaks debugging and the possibility to modify-rebuild-relaunch from inside Xcode.

Select the Cross-platform tab then under the Other template group select the Empty project type.

Createselect a temporary directory to contain the project and then click Create.

Now, right click on the root item, select Add files to, select all the files and directories in your source directory, untick Copy items if needed, then click Add.

These will then be progressively added under the root item in the left-hand pane.

Note that subdirectories may initially appear to be empty, but they too will progressively be populated as Xcode processes the sourse files.

Once done, you should be able to open any file quickly by hitting Cmd-Shift-O and typing in the name of a file.).

After you click OK, Xcode should open the settings window for the new scheme.

If not, then open its settings from the Product Edit Scheme menu.).

A new dialog titled Choose an executable to launch will pop up.

Browse to the.app file that you want to debug ( Firefox.app, Nightly Debug.app etc).

The.app file is typically found inside the dist folder in your build directory.

Mozilla Firefox For Mac Os X