feat: add warn-unused for fmt command

Author: ldez

.golangci.next.reference.yml

@@ -4016,6 +4016,9 @@ formatters:
       chain-split-dots: false
 
   exclusions:
+    # Log a warning if an exclusion path is unused.
+    # Default: false
+    warn-unused: true
     # Mode of the generated files analysis.
     #
     # - `strict`: sources are excluded by strictly following the Go generated file convention.

jsonschema/golangci.next.jsonschema.json

@@ -4624,6 +4624,10 @@
               "items": {
                 "type": "string"
               }
+            },
+            "warn-unused": {
+              "type": "boolean",
+              "default": false
             }
           }
         }

pkg/config/formatters.go

@@ -22,6 +22,7 @@ func (f *Formatters) Validate() error {
 }
 
 type FormatterExclusions struct {
-	Generated string   `mapstructure:"generated"`
-	Paths     []string `mapstructure:"paths"`
+	Generated  string   `mapstructure:"generated"`
+	Paths      []string `mapstructure:"paths"`
+	WarnUnused bool     `mapstructure:"warn-unused"`
 }

pkg/goformat/runner.go

@@ -66,6 +66,14 @@ func (c *Runner) Run(paths []string) error {
 		}
 	}
 
+	for pattern, count := range c.opts.excludedPathCounter {
+		if c.opts.warnUnused && count == 0 {
+			c.log.Warnf("The pattern %q match %d issues", pattern, count)
+		} else {
+			c.log.Infof("Skipped %d issues by pattern %q", count, pattern)
+		}
+	}
+
 	return nil
 }
 
@@ -169,6 +177,9 @@ type RunnerOptions struct {
 	generated string
 	diff      bool
 	stdin     bool
+
+	warnUnused          bool
+	excludedPathCounter map[*regexp.Regexp]int
 }
 
 func NewRunnerOptions(cfg *config.Config, diff, stdin bool) (RunnerOptions, error) {
@@ -178,10 +189,12 @@ func NewRunnerOptions(cfg *config.Config, diff, stdin bool) (RunnerOptions, erro
 	}
 
 	opts := RunnerOptions{
-		basePath:  basePath,
-		generated: cfg.Formatters.Exclusions.Generated,
-		diff:      diff,
-		stdin:     stdin,
+		basePath:            basePath,
+		generated:           cfg.Formatters.Exclusions.Generated,
+		diff:                diff,
+		stdin:               stdin,
+		excludedPathCounter: make(map[*regexp.Regexp]int),
+		warnUnused:          cfg.Formatters.Exclusions.WarnUnused,
 	}
 
 	for _, pattern := range cfg.Formatters.Exclusions.Paths {
@@ -191,6 +204,7 @@ func NewRunnerOptions(cfg *config.Config, diff, stdin bool) (RunnerOptions, erro
 		}
 
 		opts.patterns = append(opts.patterns, exp)
+		opts.excludedPathCounter[exp] = 0
 	}
 
 	return opts, nil
@@ -208,6 +222,7 @@ func (o RunnerOptions) MatchAnyPattern(path string) (bool, error) {
 
 	for _, pattern := range o.patterns {
 		if pattern.MatchString(rel) {
+			o.excludedPathCounter[pattern]++
 			return true, nil
 		}
 	}