Conviction reversed because prosecutor broke a promise to the defendant

I have posted numerous stories on courts reversing convictions because of the conduct of a prosecutor.  Most of the time, the conduct related to the duty to disclose exculpatory evidence, to comments in front of the jury or to conduct during the trial.  Recently, there were a few cases involving the misuse of powerpoint... 

But I don't remember seeing a case where the conviction was reversed because of a broken promise to the defendant.  The facts of the case are simple.  The prosecutor promised to drop charges of tampering with evidence if the defendant produced the weapon used during a crime.  The defendant produced it, but the prosecutor did not drop the charges.  As a result, the New Mexico Supreme Court vacated the conviction stating that a plea-bargained sentence must be fulfilled by the prosecution, or it will be enforced by the courts."  The case is State of New Mexico v. King, and it is available here.

This makes sense to me but I wonder if the court should have imposed sanctions on the prosecutor.  As I have argued innumerable times before, courts need to do more to curb prosecutorial misconduct.