Return error early if program is a tombstone

[pgarg66]

Problem

The program cache could contain a tombstone for a program (e.g. if it failed verification, or was closed). It's already detected early in accounts.rs. But it currently returns error from BPF loader. The check could be made early and error could be returned earlier in the processing pipeline.

Summary of Changes

Return early if the program cache contains a tombstone for the program.

Fixes #

[codecov]

Codecov Report

Merging #30940 (8e195ed) into master (bf986d6) will increase coverage by 0.0%.
The diff coverage is 87.6%.

@@           Coverage Diff            @@
##           master   #30940    +/-   ##
========================================
  Coverage    81.5%    81.5%            
========================================
  Files         727      727            
  Lines      205166   205442   +276     
========================================
+ Hits       167295   167542   +247     
- Misses      37871    37900    +29     

[Lichtso]

Currently CPI only fails if an execution is actually attempted. With this it would also fail if a transaction just references an invalid program, without using it. Thus, we need a feature gate: Either find an existing one (which was introduced in this version) to add it to or create a new one.

[pgarg66]

Currently CPI only fails if an execution is actually attempted. With this it would also fail if a transaction just references an invalid program, without using it. Thus, we need a feature gate: Either find an existing one (which was introduced in this version) to add it to or create a new one.

That's a good point. I have added a feature gate on the check.