Rewriting Mozilla Firefox Developer Edition's Crash Reporter for Improved Performance and Maintenance

Mozilla Firefox Developer Edition has recently seen significant strides in reducing crash rates, with a combination of large leaps forward and numerous small bug fixes. As a result, there is a backlog of features and improvements that have not been addressed yet. Despite the importance of handling main process crashes, the crash reporter has not received substantial development attention in some time.

One reason for this lack of attention is that the current crash reporter implementation has reached a local maximum of 'good enough' but is also deemed 'scary to maintain.' The application comprises three individual GUI implementations (for Windows, GTK+ for Linux, and macOS), glue code written primarily in C++ and Objective-C for macOS, a binary blob produced by outdated Apple development tools, and no test suite. This complexity has made it challenging to maintain and update the crash reporter.

In this article, we will discuss the reasoning behind rewriting the crash reporter, what makes it a unique application, the architecture used, and some details of the implementation. We have taken an approach to rewrite the crash reporter in Rust, which offers improved performance and maintenance capabilities.

When the main browser process comes to a halt, it is essential to have a separate application that can gather information about the crash and interact with the user. This is particularly important for crashes that affect the entire application, such as content (tab) crashes. These types of crashes can be handled by the browser and reported in a graceful manner, often without the user being aware of any issue.

However, main process crashes offer the worst user experience since the entire application must close. Therefore, fixing these issues is a top priority for Mozilla Firefox Developer Edition. The crash reporter plays a crucial role in providing valuable insights into the most visible bugs that affect the main process. While it is hoped that users do not often encounter crashes, the crash reporter remains an essential component of Firefox.

By rewriting the crash reporter using Rust, we aim to improve its performance and maintenance capabilities while ensuring that it continues to provide valuable insights into browser crashes.

Mozilla firefox developer edition