Truncate funcname to avoid long key names

.pre-commit-config.yaml

@@ -5,6 +5,6 @@ repos:
     - id: black
       language_version: python3.7
 -   repo: https://github.com/pre-commit/pre-commit-hooks
-    rev: v2.2.3
+    rev: v2.3.0
     hooks:
     - id: flake8

dask/tests/test_utils.py

@@ -324,6 +324,17 @@ class Foo(object):
     assert "Foo" in funcname(Foo())
 
 
+def test_funcname_long():
+    def a_long_function_name_11111111111111111111111111111111111111111111111():
+        pass
+
+    result = funcname(
+        a_long_function_name_11111111111111111111111111111111111111111111111
+    )
+    assert "a_long_function_name" in result
+    assert len(result) < 60
+
+
 def test_funcname_toolz():
     toolz = pytest.importorskip("toolz")
 

dask/utils.py

@@ -675,26 +675,26 @@ def funcname(func):
         return funcname(func.func)
     # methodcaller
     if isinstance(func, methodcaller):
-        return func.method
+        return func.method[:50]
 
     module_name = getattr(func, "__module__", None) or ""
     type_name = getattr(type(func), "__name__", None) or ""
 
     # toolz.curry
     if "toolz" in module_name and "curry" == type_name:
-        return func.func_name
+        return func.func_name[:50]
     # multipledispatch objects
     if "multipledispatch" in module_name and "Dispatcher" == type_name:
-        return func.name
+        return func.name[:50]
 
     # All other callables
     try:
         name = func.__name__
         if name == "<lambda>":
             return "lambda"
-        return name
+        return name[:50]
     except AttributeError:
-        return str(func)
+        return str(func)[:50]
 
 
 def typename(typ):