add Mbpp instruct (#2995)

* feat: add mbpp_instruct

* fix: update generation_kwargs to use an empty until list

* fix: correct predictions formatting in pass_at_1 function

* fix: improve code block extraction by checking first without opening backticks

* fix mbpp `pass_at_1`

lm_eval/tasks/mbpp/mbpp_instruct.yaml

+task: mbpp_instruct
+dataset_path: google-research-datasets/mbpp
+dataset_name: full
+unsafe_code: true
+output_type: generate_until
+test_split: test
+doc_to_text: "You are an expert Python programmer, and here is your task:\n{{text}}\nYour code should pass these tests:\n{{test_list[0]}}\n{{test_list[1]}}\n{{test_list[2]}}"
+doc_to_target: "{% if is_fewshot is defined %}{{code}}\n```{% else %}{{test_list[0]}}\n{{test_list[1]}}\n{{test_list[2]}}{% endif %}"
+gen_prefix: "\n```python\n"
+target_delimiter: ""
+metric_list:
+  - metric: !function utils.pass_at_1
+    aggregation: mean
+    higher_is_better: true
+filter_list:
+  - name: "extract_code"
+    filter:
+      - function: "custom"
+        filter_fn: !function utils.build_predictions
+generation_kwargs:
+  max_gen_toks: 256
+  until: []
+  do_sample: false
+num_fewshot: 3
+fewshot_config:
+  sampler: first_n
+  samples: !function utils.list_fewshot_samples
+metadata:
+  version: 1.0

lm_eval/tasks/mbpp/mbpp_plus_instruct.yaml

+include: mbpp_instruct.yaml
+task: mbpp_plus_instruct
+dataset_path: evalplus/mbppplus
+dataset_name: null
+doc_to_text: "{{prompt if prompt is defined else text}} Your code should satisfy the following assertion:\n{{test_list[0]}}"
+doc_to_target: "{{test_list[0]}}"
+gen_prefix: "Here is a solution to this programming problem:\n```python\n"
+num_fewshot: 0
+generation_kwargs:
+  max_gen_toks: 1024
+  until: []
+  do_sample: false

lm_eval/tasks/mbpp/utils.py

+import re
+from typing import Union
+
 import evaluate as hf_evaluate
 
 
@@ -12,14 +15,41 @@ except Exception as e:
     raise e
 
 
-def pass_at_1(references, predictions):
+def pass_at_1(
+    references: Union[str, list[str]], predictions: Union[str, list[list[str]]]
+) -> float:
+    if isinstance(references, str):
+        references = [references]
+    if isinstance(predictions[0], str):
+        predictions = [[p] for p in predictions]
+    print(f"References: {references}")
+    print(f"Predictions: {predictions}")
     return pass_at_k.compute(
         references=references,
-        predictions=[predictions],
+        predictions=predictions,
         k=[1],
     )[0]["pass@1"]
 
 
+def extract_code_blocks(text: str) -> str:
+    # Pattern to match ```...``` blocks
+    pattern = r"```(?:\w+)?\n?(.*?)\n?```"
+    # (+ ```) as we add the opening "```python" to the gen_prefix
+    matches = re.findall(pattern, r"```" + text, re.DOTALL)
+    # if no matches, try to match ```...``` blocks (after removing the language)
+    if not matches:
+        text_without_lang = re.sub(r"```python", "```", text)
+        matches = re.findall(pattern, text_without_lang, re.DOTALL)
+    if not matches:
+        return ""
+    else:
+        return matches[0]
+
+
+def build_predictions(resps: list[list[str]], docs: list[dict]) -> list[list[str]]:
+    return [[extract_code_blocks(r) for r in resp] for resp in resps]
+
+
 def list_fewshot_samples():
     return [
         {