Add except-function-name-pattern option to argument-always-wildcard (#924)

And have functions starting with "mock_" excepted by default.

Fixes #923

Signed-off-by: Anders Eknert <anders@styra.com>

Author: anderseknert

bundle/regal/config/provided/data.yaml

@@ -7,6 +7,7 @@ rules:
       level: error
     argument-always-wildcard:
       level: error
+      except-function-name-pattern: "^mock_"
     constant-condition:
       level: error
     deprecated-builtin:

bundle/regal/rules/bugs/argument_always_wildcard.rego

@@ -5,10 +5,11 @@ package regal.rules.bugs["argument-always-wildcard"]
 import rego.v1
 
 import data.regal.ast
+import data.regal.config
 import data.regal.result
 
 report contains violation if {
-	some functions in _function_groups
+	some name, functions in _function_groups
 
 	fn := _any_member(functions)
 
@@ -19,6 +20,8 @@ report contains violation if {
 		startswith(function.head.args[pos].value, "$")
 	}
 
+	not _function_name_excepted(config.for_rule("bugs", "argument-always-wildcard"), name)
+
 	violation := result.fail(rego.metadata.chain(), result.ranged_location_from_text(fn.head.args[pos]))
 }
 
@@ -28,4 +31,6 @@ _function_groups[name] contains fn if {
 	name := ast.ref_to_string(fn.head.ref)
 }
 
+_function_name_excepted(cfg, name) if regex.match(cfg["except-function-name-pattern"], name)
+
 _any_member(s) := [x | some x in s][0]

bundle/regal/rules/bugs/argument_always_wildcard_test.rego

@@ -26,6 +26,15 @@ test_fail_single_function_single_argument_always_a_wildcard if {
 	}}
 }
 
+test_success_single_function_single_argument_always_a_wildcard_except_function_name if {
+	module := ast.with_rego_v1(`
+	mock_f(_) := 1
+	`)
+
+	r := rule.report with input as module with config.for_rule as {"except-function-name-pattern": "^mock_"}
+	r == set()
+}
+
 test_fail_single_argument_always_a_wildcard if {
 	module := ast.with_rego_v1(`
 	f(_) := 1

docs/rules/bugs/argument-always-wildcard.md

@@ -85,6 +85,10 @@ rules:
     argument-always-wildcard:
       # one of "error", "warning", "ignore"
       level: error
+      # function name patterns for which this rule should make an exception
+      # default is to ignore any function name starting with "mock_" as these
+      # commonly don't need named arguments
+      except-function-name-pattern: "^mock_"
 ```
 
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