python-graphblas · eriknw · Jul 31, 2026
diff --git a/graphblas/agg/__init__.py b/graphblas/agg/__init__.py
@@ -109,7 +109,9 @@ def __getattr__(key):
         ss = import_module(".ss", __name__)
         globals()["ss"] = ss
         return ss
-    raise AttributeError(f"module {__name__!r} has no attribute {key!r}")
+    from ..core.utils import _module_attr_error
+
+    raise _module_attr_error(__name__, key, __dir__())
 
 
 from ..core import operator  # noqa: E402 isort:skip

diff --git a/graphblas/binary/__init__.py b/graphblas/binary/__init__.py
@@ -66,7 +66,9 @@ def __getattr__(key):
             f"module {__name__!r} unable to compile UDF for {key!r}; "
             "install numba for UDF support"
         )
-    raise AttributeError(f"module {__name__!r} has no attribute {key!r}")
+    from ..core.utils import _module_attr_error
+
+    raise _module_attr_error(__name__, key, __dir__())
 
 
 from ..core import operator  # noqa: E402 isort:skip

diff --git a/graphblas/core/utils.py b/graphblas/core/utils.py
@@ -33,6 +33,23 @@ def inner(func_wo_doc):
     return inner
 
 
+def _module_attr_error(module_name, key, names):
+    """Build the AttributeError raised by an operator namespace's ``__getattr__``.
+
+    ``names`` should be the module's ``__dir__()`` so lazily-registered operators
+    are offered as "did you mean" suggestions without forcing them to build.
+    """
+    import difflib
+
+    msg = f"module {module_name!r} has no attribute {key!r}"
+    candidates = [name for name in names if not name.startswith("_")]
+    matches = difflib.get_close_matches(key, candidates, n=3)
+    if matches:
+        hint = " or ".join(repr(match) for match in matches)
+        msg = f"{msg}. Did you mean {hint}?"
+    return AttributeError(msg)
+
+
 # Include most common types (even mistakes)
 _output_types = {
     int: int,

diff --git a/graphblas/indexunary/__init__.py b/graphblas/indexunary/__init__.py
@@ -25,7 +25,9 @@ def __getattr__(key):
         ss = import_module(".ss", __name__)
         globals()["ss"] = ss
         return ss
-    raise AttributeError(f"module {__name__!r} has no attribute {key!r}")
+    from ..core.utils import _module_attr_error
+
+    raise _module_attr_error(__name__, key, __dir__())
 
 
 from ..core import operator  # noqa: E402 isort:skip

diff --git a/graphblas/monoid/__init__.py b/graphblas/monoid/__init__.py
@@ -29,7 +29,9 @@ def __getattr__(key):
         ss = import_module(".ss", __name__)
         globals()["ss"] = ss
         return ss
-    raise AttributeError(f"module {__name__!r} has no attribute {key!r}")
+    from ..core.utils import _module_attr_error
+
+    raise _module_attr_error(__name__, key, __dir__())
 
 
 from ..core import operator  # noqa: E402 isort:skip

diff --git a/graphblas/op/__init__.py b/graphblas/op/__init__.py
@@ -47,7 +47,9 @@ def __getattr__(key):
                 f"module {__name__!r} unable to compile UDF for {key!r}; "
                 "install numba for UDF support"
             )
-    raise AttributeError(f"module {__name__!r} has no attribute {key!r}")
+    from ..core.utils import _module_attr_error
+
+    raise _module_attr_error(__name__, key, __dir__())
 
 
 from ..core import operator, _supports_udfs  # noqa: E402 isort:skip

diff --git a/graphblas/select/__init__.py b/graphblas/select/__init__.py
@@ -29,7 +29,9 @@ def __getattr__(key):
         ss = import_module(".ss", __name__)
         globals()["ss"] = ss
         return ss
-    raise AttributeError(f"module {__name__!r} has no attribute {key!r}")
+    from ..core.utils import _module_attr_error
+
+    raise _module_attr_error(__name__, key, __dir__())
 
 
 def _resolve_expr(expr, callname, opname):

diff --git a/graphblas/semiring/__init__.py b/graphblas/semiring/__init__.py
@@ -74,7 +74,9 @@ def __getattr__(key):
             f"module {__name__!r} unable to compile UDF for {key!r}; "
             "install numba for UDF support"
         )
-    raise AttributeError(f"module {__name__!r} has no attribute {key!r}")
+    from ..core.utils import _module_attr_error
+
+    raise _module_attr_error(__name__, key, __dir__())
 
 
 from ..core import operator  # noqa: E402 isort:skip

diff --git a/graphblas/tests/test_op.py b/graphblas/tests/test_op.py
@@ -3725,3 +3725,37 @@ def test_compile_codegen_helper():
     assert "Source:" in msg
     assert bad_src in msg
     assert isinstance(exc_info.value.__cause__, SyntaxError)
+
+
+def test_operator_namespace_typo_suggestions():
+    # A typo in an operator namespace should suggest close matches (via difflib),
+    # drawn from __dir__() so lazily-registered operators are offered without
+    # forcing them to build.
+    with pytest.raises(AttributeError, match="has no attribute 'pluss'.*Did you mean 'plus'"):
+        binary.pluss
+    with pytest.raises(AttributeError, match="Did you mean 'plus'"):
+        monoid.pluss
+    with pytest.raises(AttributeError, match="plus_times"):
+        semiring.plus_time
+    with pytest.raises(AttributeError, match="Did you mean 'sum'"):
+        agg.summ
+    with pytest.raises(AttributeError, match="Did you mean"):
+        unary.expp
+    with pytest.raises(AttributeError, match="rowindex"):
+        indexunary.rowindexx
+    with pytest.raises(AttributeError, match="triu"):
+        select.triu_typo
+    with pytest.raises(AttributeError, match="Did you mean 'plus'"):
+        op.pluss
+
+    # No close match -> plain message, no suggestion appended
+    with pytest.raises(AttributeError) as exc_info:
+        binary.zzzzzz
+    assert "has no attribute 'zzzzzz'" in str(exc_info.value)
+    assert "Did you mean" not in str(exc_info.value)
+
+    # Building suggestions must not force lazy operators to compile
+    before = set(binary._delayed)
+    with pytest.raises(AttributeError):
+        binary.pluss
+    assert set(binary._delayed) == before
diff --git a/graphblas/unary/__init__.py b/graphblas/unary/__init__.py
@@ -42,7 +42,9 @@ def __getattr__(key):
         ss = import_module(".ss", __name__)
         globals()["ss"] = ss
         return ss
-    raise AttributeError(f"module {__name__!r} has no attribute {key!r}")
+    from ..core.utils import _module_attr_error
+
+    raise _module_attr_error(__name__, key, __dir__())
 
 
 from ..core import operator  # noqa: E402 isort:skip