Give some helpful info on a suspected serialization error

Motivated by some requests in #help and by the fact that diagnosing and
fixing serialization-related errors is currently a rather arcane task.

compute_sdk/globus_compute_sdk/errors/error_types.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+import re
 import textwrap
 import time
 
@@ -70,11 +71,31 @@ def __str__(self) -> str:
         )
 
 
+SERDE_TASK_EXECUTION_FAILED_HELP_MESSAGE = """
+
+This appears to be an error with serialization. If it is, using a different
+serialization strategy from globus_compute_sdk.serialize might resolve the issue. For
+example, to use globus_compute_sdk.serialize.CombinedCode:
+
+    from globus_compute_sdk import Client, Executor
+    from globus_compute_sdk.serialize import CombinedCode
+
+    gcc = Client(code_serialization_strategy=CombinedCode())
+    with Executor('<your-endpoint-id>', client=gcc) as gcx:
+        # do something with gcx
+
+For more information, see:
+    https://globus-compute.readthedocs.io/en/latest/sdk.html#specifying-a-serialization-strategy
+"""
+
+
 class TaskExecutionFailed(Exception):
     """
     Error result from the remote end, wrapped as an exception object
     """
 
+    SERDE_REGEX = re.compile("dill|pickle|serializ", re.IGNORECASE)
+
     def __init__(
         self,
         remote_data: str,
@@ -87,4 +108,8 @@ def __init__(
         self.completion_t = completion_t or str(time.time())
 
     def __str__(self) -> str:
-        return "\n" + textwrap.indent(self.remote_data, " ")
+        remote_data = textwrap.indent(self.remote_data, " ")
+        message = "\n" + remote_data
+        if re.search(TaskExecutionFailed.SERDE_REGEX, remote_data):
+            message += SERDE_TASK_EXECUTION_FAILED_HELP_MESSAGE
+        return message

compute_sdk/tests/unit/test_error_types.py

@@ -0,0 +1,27 @@
+import traceback
+from functools import lru_cache
+
+import pytest
+from globus_compute_sdk.errors import TaskExecutionFailed
+from globus_compute_sdk.serialize import DillCodeSource
+
+
+@lru_cache(maxsize=None)
+def annotated_function():
+    return "data"
+
+
+def test_task_execution_failed_serialization_help_msg():
+    try:
+        DillCodeSource().serialize(annotated_function)
+    except OSError:
+        tb = traceback.format_exc()
+    else:
+        pytest.fail("Expected DillCodeSource to fail to serialize annotated functions")
+
+    tef = TaskExecutionFailed(tb)
+    assert "This appears to be an error with serialization." in str(tef)
+    assert (
+        "https://globus-compute.readthedocs.io/en/latest/sdk.html"
+        "#specifying-a-serialization-strategy" in str(tef)
+    )