Bitbucket Server interprets Objective-C file as Mathematica file <Uncaught Error: Mode mathematica failed to advance stream.>

Summary

User created a pull request for a branch that contained Objective-C file with the .m file extension.

In the diff view of the pull request the file preview is blank.

Viewing the page with chrome devtools this is seen in the error console:

Uncaught Error: Mode mathematica failed to advance stream.

Steps to reproduce

1. Add, commit and push a file with a .m extension that includes a special character like ©.

Example source code to use for testing:

//
//  Words
//  Words
//
//  Words
//  Words © 
//

1. Check source view for the file.
2. Create pull request and check file preview in diff view

Expected Results

The file's contents should be displayed.

Actual Results

In Chrome the file contents are seen briefly before disappearing.
In Firefox the view is just blank.

WorkAround

As per this reference Bitbucket Server can be told to regard files with the .m file extension as Objective-C files.

In this case the following was added to the $BITBUCKET_HOME/shared/bitbucket.properties file:

syntax.highlighter.text/x-objectivec.extensions=m