Fix nth highlighting

Fix #4222

src/core.go

@@ -195,15 +195,14 @@ func Run(opts *Options) (int, error) {
 	}
 
 	nth := opts.Nth
-	nthRevision := 0
+	inputRevision := revision{}
+	snapshotRevision := revision{}
 	patternCache := make(map[string]*Pattern)
 	patternBuilder := func(runes []rune) *Pattern {
 		return BuildPattern(cache, patternCache,
 			opts.Fuzzy, opts.FuzzyAlgo, opts.Extended, opts.Case, opts.Normalize, forward, withPos,
-			opts.Filter == nil, nth, opts.Delimiter, nthRevision, runes)
+			opts.Filter == nil, nth, opts.Delimiter, inputRevision, runes)
 	}
-	inputRevision := revision{}
-	snapshotRevision := revision{}
 	matcher := NewMatcher(cache, patternBuilder, sort, opts.Tac, eventBox, inputRevision)
 
 	// Filtering mode
@@ -382,7 +381,6 @@ func Run(opts *Options) (int, error) {
 						if val.nth != nil {
 							// Change nth and clear caches
 							nth = *val.nth
-							nthRevision++
 							patternCache = make(map[string]*Pattern)
 							cache.Clear()
 							inputRevision.bumpMinor()

src/item.go

@@ -9,7 +9,7 @@ import (
 type transformed struct {
 	// Because nth can be changed dynamically by change-nth action, we need to
 	// keep the revision number at the time of transformation.
-	revision int
+	revision revision
 	tokens   []Token
 }
 

src/pattern.go

@@ -60,7 +60,7 @@ type Pattern struct {
 	cacheKey      string
 	delimiter     Delimiter
 	nth           []Range
-	revision      int
+	revision      revision
 	procFun       map[termType]algo.Algo
 	cache         *ChunkCache
 }
@@ -73,7 +73,7 @@ func init() {
 
 // BuildPattern builds Pattern object from the given arguments
 func BuildPattern(cache *ChunkCache, patternCache map[string]*Pattern, fuzzy bool, fuzzyAlgo algo.Algo, extended bool, caseMode Case, normalize bool, forward bool,
-	withPos bool, cacheable bool, nth []Range, delimiter Delimiter, revision int, runes []rune) *Pattern {
+	withPos bool, cacheable bool, nth []Range, delimiter Delimiter, revision revision, runes []rune) *Pattern {
 
 	var asString string
 	if extended {

src/pattern_test.go

@@ -68,7 +68,7 @@ func buildPattern(fuzzy bool, fuzzyAlgo algo.Algo, extended bool, caseMode Case,
 	withPos bool, cacheable bool, nth []Range, delimiter Delimiter, runes []rune) *Pattern {
 	return BuildPattern(NewChunkCache(), make(map[string]*Pattern),
 		fuzzy, fuzzyAlgo, extended, caseMode, normalize, forward,
-		withPos, cacheable, nth, delimiter, 0, runes)
+		withPos, cacheable, nth, delimiter, revision{}, runes)
 }
 
 func TestExact(t *testing.T) {

src/terminal.go

@@ -2932,7 +2932,7 @@ func (t *Terminal) printHighlighted(result Result, colBase tui.ColorPair, colMat
 		}
 		if !wholeCovered && t.nthAttr > 0 {
 			var tokens []Token
-			if item.transformed != nil {
+			if item.transformed != nil && item.transformed.revision == t.merger.revision {
 				tokens = item.transformed.tokens
 			} else {
 				tokens = Transform(Tokenize(item.text.ToString(), t.delimiter), t.nthCurrent)