Enable the appendAssign lint check (#1865)

* Make copies of buffers

Avoid reusing one of the incoming arrays as a append extension, and
make a copy of the data. It's cleaner in the long run and possibly
easier for the GC to maintain.

* Avoid appendAssign problems in tag code

Reuse the existing slice when appending.

* Fix appendAssign in encoder_scene_preview_chunk

Appending and creating a new slice is somewhat unintuitive since the
underlying slice might be extended to satisfy the new capacity. This
sometimes leads to faulty logic.

Rewrite the code so it reuses `args` for all appending, and builds one
array clearly in the code. It follows the general style of the function
where `args` is being built in small incremental batches and avoids
the introduction of new names.

* Enable the appendAssign check

This makes us pass all gocritic warnings.

Co-authored-by: WithoutPants <53250216+WithoutPants@users.noreply.github.com>

.golangci.yml

@@ -36,10 +36,6 @@ linters:
 
 # Project-specific linter overrides
 linters-settings:
-  gocritic:
-    disabled-checks:
-      - appendAssign
-
   gofmt:
     simplify: false
 

pkg/autotag/scene_test.go

@@ -67,7 +67,8 @@ func generateFalseNamePatterns(name string, separator, ext string) []string {
 }
 
 func generateTestPaths(testName, ext string) (scenePatterns []string, falseScenePatterns []string) {
-	separators := append(testSeparators, testEndSeparators...)
+	separators := testSeparators
+	separators = append(separators, testEndSeparators...)
 
 	for _, separator := range separators {
 		scenePatterns = append(scenePatterns, generateNamePatterns(testName, separator, ext)...)
@@ -115,7 +116,8 @@ func generateTestTable(testName, ext string) []pathTestTable {
 	var scenePatterns []string
 	var falseScenePatterns []string
 
-	separators := append(testSeparators, testEndSeparators...)
+	separators := testSeparators
+	separators = append(separators, testEndSeparators...)
 
 	for _, separator := range separators {
 		scenePatterns = append(scenePatterns, generateNamePatterns(testName, separator, ext)...)

pkg/ffmpeg/encoder_scene_preview_chunk.go

@@ -85,11 +85,11 @@ func (e *Encoder) ScenePreviewVideoChunk(probeResult VideoFile, options ScenePre
 		"-strict", "-2",
 	}
 
-	args3 := append(args, args2...)
+	args = append(args, args2...)
-	args3 = append(args3, argsAudio...)
+	args = append(args, argsAudio...)
-	finalArgs := append(args3, options.OutputPath)
+	args = append(args, options.OutputPath)
 
-	_, err := e.run(probeResult.Path, finalArgs, nil)
+	_, err := e.run(probeResult.Path, args, nil)
 	return err
 }
 

pkg/sqlite/tag.go

@@ -649,13 +649,13 @@ func (qb *tagQueryBuilder) Merge(source []int, destination int) error {
 		"performers_tags":    "performer_id",
 	}
 
-	tagArgs := append(args, destination)
+	args = append(args, destination)
 	for table, idColumn := range tagTables {
 		_, err := qb.tx.Exec(`UPDATE `+table+`
 SET tag_id = ?
 WHERE tag_id IN `+inBinding+`
 AND NOT EXISTS(SELECT 1 FROM `+table+` o WHERE o.`+idColumn+` = `+table+`.`+idColumn+` AND o.tag_id = ?)`,
-			tagArgs...,
+			args...,
 		)
 		if err != nil {
 			return err