Link detected cookies to existing patterns on conflict

When a cookie pattern already exists for a banner, the insert
conflict caused a continue that silently dropped the detected
cookie instead of linking it to the existing pattern. Load the
existing pattern to obtain its ID and proceed with cookie
insertion.

Signed-off-by: Émile Ré <emile@getprobo.com>

pkg/cookiebanner/errors.go

@@ -29,9 +29,9 @@ var (
 	ErrCategorySlugAlreadyExists  = errors.New("a category with this slug already exists in this banner")
 	ErrOriginAlreadyInUse         = errors.New("origin is already used by another active cookie banner")
 	ErrConsentNotFound            = errors.New("consent record not found")
-	ErrCookieNotFound            = errors.New("cookie not found")
-	ErrCategoriesBannerMismatch  = errors.New("source and target categories belong to different banners")
-	ErrPostHogConsentKindInvalid = errors.New("PostHog consent can only be enabled on normal categories")
+	ErrCookieNotFound             = errors.New("cookie not found")
+	ErrCategoriesBannerMismatch   = errors.New("source and target categories belong to different banners")
+	ErrPostHogConsentKindInvalid  = errors.New("PostHog consent can only be enabled on normal categories")
 	ErrCookiePatternNotFound      = errors.New("cookie pattern not found")
 	ErrPatternAlreadyExists       = errors.New("a pattern with this name already exists in this banner")
 	ErrSamePatternCategoryMove    = errors.New("source and target cookie categories must be different")

pkg/cookiebanner/service.go

@@ -2286,11 +2286,16 @@ func (s *Service) ReportDetectedCookies(
 					if err != nil {
 						return fmt.Errorf("cannot insert cookie pattern: %w", err)
 					}
-					if !wasInserted {
-						continue
+					if wasInserted {
+						patternID = newPattern.ID
+						inserted++
+					} else {
+						var existingPattern coredata.CookiePattern
+						if err := existingPattern.LoadByBannerIDAndPattern(ctx, tx, scope, banner.ID, dc.Name); err != nil {
+							return fmt.Errorf("cannot load existing cookie pattern: %w", err)
+						}
+						patternID = existingPattern.ID
 					}
-					patternID = newPattern.ID
-					inserted++
 				}
 
 				cookie := &coredata.Cookie{