Fixed import log output duplicating

CHANGES.md

@@ -17,6 +17,7 @@
 - deezer: fixed endless export loop if the user's listen history was empty.
 - dump: it is now possible to specify a file to write the text output to.
 - Fixed potential issues with MusicBrainz rate limiting.
+- Fixed import log output duplicating.
 
 
 ## 0.6.0 - 2025-05-23

internal/backends/import.go

@@ -112,8 +112,9 @@ func process[R models.LovesResult | models.ListensResult, P ImportProcessor[R]](
 			return
 		}
 
-		importResult, err := processor.Import(ctx, exportResult, result, out, progress)
-		result.Update(importResult)
+		importResult, err := processor.Import(
+			ctx, exportResult, result.Copy(), out, progress)
+		result.Update(&importResult)
 		if err != nil {
 			processor.ImportBackend().FinishImport()
 			out <- handleError(result, err, progress)

internal/models/models.go

@@ -196,11 +196,21 @@ func (i *ImportResult) UpdateTimestamp(newTime time.Time) {
 	}
 }
 
-func (i *ImportResult) Update(from ImportResult) {
-	i.TotalCount = from.TotalCount
-	i.ImportCount = from.ImportCount
-	i.UpdateTimestamp(from.LastTimestamp)
-	i.ImportLog = append(i.ImportLog, from.ImportLog...)
+func (i *ImportResult) Update(from *ImportResult) {
+	if i != from {
+		i.TotalCount = from.TotalCount
+		i.ImportCount = from.ImportCount
+		i.UpdateTimestamp(from.LastTimestamp)
+		i.ImportLog = append(i.ImportLog, from.ImportLog...)
+	}
+}
+
+func (i *ImportResult) Copy() ImportResult {
+	return ImportResult{
+		TotalCount:    i.TotalCount,
+		ImportCount:   i.ImportCount,
+		LastTimestamp: i.LastTimestamp,
+	}
 }
 
 func (i *ImportResult) Log(t LogEntryType, msg string) {

internal/models/models_test.go

@@ -1,5 +1,5 @@
 /*
-Copyright © 2023 Philipp Wolfer <phw@uploadedlobster.com>
+Copyright © 2023-2025 Philipp Wolfer <phw@uploadedlobster.com>
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
@@ -138,13 +138,31 @@ func TestImportResultUpdate(t *testing.T) {
 		LastTimestamp: time.Now().Add(1 * time.Hour),
 		ImportLog:     []models.LogEntry{logEntry2},
 	}
-	result.Update(newResult)
+	result.Update(&newResult)
 	assert.Equal(t, 120, result.TotalCount)
 	assert.Equal(t, 50, result.ImportCount)
 	assert.Equal(t, newResult.LastTimestamp, result.LastTimestamp)
 	assert.Equal(t, []models.LogEntry{logEntry1, logEntry2}, result.ImportLog)
 }
 
+func TestImportResultCopy(t *testing.T) {
+	logEntry := models.LogEntry{
+		Type:    models.Warning,
+		Message: "foo",
+	}
+	result := models.ImportResult{
+		TotalCount:    100,
+		ImportCount:   20,
+		LastTimestamp: time.Now(),
+		ImportLog:     []models.LogEntry{logEntry},
+	}
+	copy := result.Copy()
+	assert.Equal(t, result.TotalCount, copy.TotalCount)
+	assert.Equal(t, result.ImportCount, copy.ImportCount)
+	assert.Equal(t, result.LastTimestamp, copy.LastTimestamp)
+	assert.Empty(t, copy.ImportLog)
+}
+
 func TestImportResultLog(t *testing.T) {
 	result := models.ImportResult{}
 	result.Log(models.Warning, "foo")