Pref Comment Cleanup

Inline comments in firefox.js were breaking the Sphinx extension’s parser. Moving them to line comments fixed it.

Bug 2020396 | D286360 | Reviewer: manuel

The Problem

The Sphinx extension parses firefox.js with regex to extract pref values. The cookieBehavior prefs had inline comments after the value:

pref("network.cookie.cookieBehavior", 5 /* BEHAVIOR_REJECT_TRACKER_AND_PARTITION_FOREIGN */);

The parser was picking up 5 /* BEHAVIOR_REJECT_TRACKER_AND_PARTITION_FOREIGN */ as the value instead of just 5. Rather than making the regex more complex to handle inline comments, the simpler fix was to move the comments above the pref declaration.

The Fix

// Before:
pref("network.cookie.cookieBehavior", 5 /* BEHAVIOR_REJECT_TRACKER_AND_PARTITION_FOREIGN */);
pref("network.cookie.cookieBehavior.pbmode", 5 /* BEHAVIOR_REJECT_TRACKER_AND_PARTITION_FOREIGN */);

// After:
// Enable Dynamic First-Party Isolation by default (BEHAVIOR_REJECT_TRACKER_AND_PARTITION_FOREIGN).
pref("network.cookie.cookieBehavior", 5);

// Enable Dynamic First-Party Isolation in the private browsing mode (BEHAVIOR_REJECT_TRACKER_AND_PARTITION_FOREIGN).
pref("network.cookie.cookieBehavior.pbmode", 5);

One file changed, 4 lines modified. The kind of patch that takes 2 minutes to write and saves hours of debugging later.

What I Learned

1. Fix the data, not the parser. When your input format is inconsistent, it’s often cheaper and more robust to normalize the input than to make the parser handle every edge case.