Coding errors and defense rights to discovery are well discussed in this Slate article. Another example of obstacles to proving innocence. Some forensics dont even use programs. Bitemarkers and some others just use their eyeballs and “superior” observation skills. I kid you not. Its in the literature. 

http://www.slate.com/blogs/future_tense/2015/10/06/defendants_should_be_able_to_inspect_software_code_used_in_forensics.html