Scope VGI316 to table functions only (fix scalar/aggregate false positives)

RULES.md

@@ -123,7 +123,7 @@ skipped unless `--execute` is passed.
 | `VGI313` | warning | argument-description-states-type | An argument description should not restate the data type (it's a separate field). |  |
 | `VGI314` | warning | function-restates-argument-docs | A function's description shouldn't re-document its arguments (they'd drift). |  |
 | `VGI315` | warning | argument-type-consistent | An argument name should map to one SQL type across all functions (no type drift). |  |
-| `VGI316` | warning | array-argument-could-be-table | A function with a single multi-dimensional-array argument should take a table input. |  |
+| `VGI316` | warning | array-argument-could-be-table | A table function with a single multi-dimensional-array argument should take a table input. |  |
 | `VGI317` | error | constrained-argument-not-discoverable | An argument whose description enumerates allowed values or a numeric range should declare machine-readable constraints (choices / ge / le) so agents discover valid inputs. Needs a vgi extension exposing vgi_function_arguments(); silent on older ones. |  |
 | `VGI318` | error | default-violates-constraint | An argument's declared default must satisfy its own constraints — be a member of choices, inside the numeric range, and match the pattern. Needs a vgi extension exposing vgi_function_arguments(); silent on older ones. |  |
 | `VGI319` | warning | invalid-constraint | A declared constraint must be well-formed: the pattern must be a valid regex and the numeric range must be non-empty. Needs a vgi extension exposing vgi_function_arguments(). |  |

src/vgi_lint_check/rules/functions.py

@@ -798,16 +798,18 @@ class ArrayArgumentCouldBeTable(Rule):
     name = "array-argument-could-be-table"
     category = FUNC
     default_severity = Severity.WARNING
-    targets = (
-        ObjectKind.SCALAR_FUNCTION,
-        ObjectKind.AGGREGATE,
-        ObjectKind.MACRO,
-        ObjectKind.TABLE_FUNCTION,
+    # Table functions only. The remedy ("expose a table/relation input so callers
+    # pass a subquery FROM …") is only structurally possible for a table function:
+    # a scalar or aggregate function returns one value per row and cannot take a
+    # relation as an argument, and DuckDB macros take scalar expressions, not
+    # relations — flagging any of them is a false positive with no achievable fix.
+    targets = (ObjectKind.TABLE_FUNCTION,)
+    summary = (
+        "A table function with a single multi-dimensional-array argument should take a table input."
     )
-    summary = "A function with a single multi-dimensional-array argument should take a table input."
 
     def check(self, ctx: RuleContext) -> Iterator[Finding]:
-        for f in ctx.catalog.iter_all_functions():
+        for f in _iter_table_functions(ctx):
             array_args = [
                 a
                 for a in f.arguments

tests/unit/test_strict_rules.py

@@ -711,12 +711,12 @@ def test_vgi152_agent_test_tasks_present_nudge():
 
 
 def test_vgi316_single_array_arg_suggests_table():
-    def codes_for(*args):
-        fn = F.func("main", "solve", description="d", arguments=list(args))
+    def codes_for(*args, ftype="table"):
+        fn = F.func("main", "solve", ftype=ftype, description="d", arguments=list(args))
         s = F.schema("main", comment="c", tags=_TAGS, functions=[fn])
         return {f.code for f in run(select_rules(Config()), RuleContext(F.catalog(s), Config()))}
 
-    # a single 2-D array argument (a matrix / list of rows) -> fires
+    # a TABLE FUNCTION with a single 2-D array argument (a matrix / list of rows) -> fires
     assert "VGI316" in codes_for(F.arg("distance", "BIGINT[][]", "the distance matrix"))
     # a list-of-struct (typed rows) -> fires
     assert "VGI316" in codes_for(F.arg("rows", "STRUCT(a INTEGER, b INTEGER)[]", "rows"))
@@ -726,6 +726,15 @@ def codes_for(*args):
     )
     # a plain 1-D array (a vector) -> not flagged
     assert "VGI316" not in codes_for(F.arg("v", "BIGINT[]", "a vector of weights"))
+    # a SCALAR function with the same matrix arg -> NOT flagged: a scalar returns one
+    # value per row and has no table-function form, so the remedy is impossible.
+    assert "VGI316" not in codes_for(
+        F.arg("distance", "BIGINT[][]", "the distance matrix"), ftype="scalar"
+    )
+    # likewise an AGGREGATE with a matrix arg -> not flagged.
+    assert "VGI316" not in codes_for(
+        F.arg("distance", "BIGINT[][]", "the distance matrix"), ftype="aggregate"
+    )
 
 
 def test_vgi145_view_wraps_table_function():