fix: support filters through strings or files

#967

Author: jdkato

internal/check/filter.go

@@ -12,25 +12,32 @@ import (
 )
 
 func filter(mgr *Manager) (map[string]Rule, error) {
-	stringOrPath := mgr.Config.Flags.Filter
+	var filter string
 
+	stringOrPath := mgr.Config.Flags.Filter
 	if stringOrPath == "" {
 		return mgr.rules, nil
-	} else if !system.FileExists(stringOrPath) {
-		name := stringOrPath
-
-		stringOrPath = core.FindAsset(mgr.Config, name)
-		if stringOrPath == "" {
-			return nil, fmt.Errorf("filter '%s' not found", name)
-		}
 	}
 
-	b, err := os.ReadFile(stringOrPath)
-	if err != nil {
-		return nil, fmt.Errorf("failed to read filter '%s': %w", stringOrPath, err)
+	if system.FileExists(stringOrPath) {
+		// Case 1: The user has provided a valid path to a filter file.
+		b, err := os.ReadFile(stringOrPath)
+		if err != nil {
+			return nil, fmt.Errorf("failed to read filter '%s': %w", stringOrPath, err)
+		}
+		filter = string(b)
+	} else if found := core.FindAsset(mgr.Config, stringOrPath); found != "" {
+		// Case 2: The user has referenced a filter stored on the `StylesPath`.
+		b, err := os.ReadFile(found)
+		if err != nil {
+			return nil, fmt.Errorf("failed to read filter '%s': %w", found, err)
+		}
+		filter = string(b)
+	} else {
+		// Case 3: Assume the  user has provided a string.
+		filter = stringOrPath
 	}
 
-	filter := string(b)
 	// .Name, .Level -> override
 	// .Scope, .Message, .Description, .Extends, .Link
 	//

testdata/features/CLI.feature

@@ -134,7 +134,7 @@ Feature: CLI
         And the exit status should be 0
 
     Scenario: Filter --minAlertLevel
-        When I use filter "min"
+        When I use filter file "min"
         Then the output should contain exactly:
             """
             test.md:1:3:demo.Cap:'intro' should be in title case ('Intro').
@@ -143,15 +143,15 @@ Feature: CLI
         And the exit status should be 1
 
     Scenario: Filter by single scope
-        When I use filter "scope"
+        When I use filter file "scope"
         Then the output should contain exactly:
             """
             test.md:1:3:demo.Cap:'intro' should be in title case ('Intro').
             """
         And the exit status should be 1
 
     Scenario: Filter by multiple levels
-        When I use filter "levels"
+        When I use filter file "levels"
         Then the output should contain exactly:
             """
             test.md:1:3:demo.HeadingStartsWithCapital:'intro' should be capitalized
@@ -160,13 +160,29 @@ Feature: CLI
         And the exit status should be 1
 
     Scenario: Filter by extends
-        When I use filter "extends"
+        When I use filter file "extends"
         Then the output should contain exactly:
             """
             test.md:1:3:demo.HeadingStartsWithCapital:'intro' should be capitalized
             """
         And the exit status should be 0
 
+    Scenario: Filter by extends [expr]
+        When I use filter expr ".Extends in ['existence']"
+        Then the output should contain exactly:
+            """
+            test.md:1:3:demo.HeadingStartsWithCapital:'intro' should be capitalized
+            """
+        And the exit status should be 0
+
+    Scenario: Filter by multiple levels [expr]
+        When I use filter expr ".Level in ['error', 'suggestion'] and .Name != 'demo.Cap'"
+        Then the output should contain exactly:
+            """
+            test.md:1:3:demo.HeadingStartsWithCapital:'intro' should be capitalized
+            test.md:5:8:Vale.Repetition:'is' is repeated!
+            """
+
     Scenario: Script-computed suggestions
         When I fix "script.json"
         Then the output should contain exactly:

testdata/features/steps.rb

@@ -26,11 +26,16 @@
   step %(I run `#{cmd} fix #{c}`)
 end
 
-When(/^I use filter "(.*)"$/) do |f|
+When(/^I use filter file "(.*)"$/) do |f|
   step %(I cd to "../../fixtures/filters")
   step %(I run `#{cmd} --filter="#{f}.expr" .`)
 end
 
+When(/^I use filter expr "(.*)"$/) do |e|
+  step %(I cd to "../../fixtures/filters")
+  step %(I run `#{cmd} --filter="#{e}" .`)
+end
+
 When(/^I lint simple "(.*)"$/) do |flag|
   step %(I cd to "../../fixtures/formats")
   step %(I run `#{cmd} --ignore-syntax #{flag}`)