fix: "/%" early stop

Author: wjiayis

internal/libs/tex/latexpand.go

@@ -8,14 +8,20 @@ import (
 	"paperdebugger/internal/libs/shared"
 )
 
+// commentRegex matches a LaTeX comment: an unescaped % and everything after it
+// until end of line. The leading group captures either start-of-line or a
+// non-backslash character so that \% (an escaped percent) is preserved. Pairs
+// of backslashes (\\) before % are treated as a line-break followed by a real
+// comment, matching LaTeX semantics.
+var commentRegex = regexp.MustCompile(`(^|[^\\])((?:\\\\)*)%.*$`)
+
 func removeComments(text string) string {
 	// Split into lines, trim each line and filter empty ones
 	lines := strings.Split(text, "\n")
 	var result []string
 	for _, line := range lines {
 		trimmed := strings.TrimSpace(line)
-		commentRegex := regexp.MustCompile(`%.*$`)
-		cleaned := commentRegex.ReplaceAllString(trimmed, "")
+		cleaned := commentRegex.ReplaceAllString(trimmed, "$1$2")
 		cleaned = strings.TrimSpace(cleaned)
 		if len(cleaned) == 0 {
 			continue

internal/libs/tex/latexpand_test.go

@@ -20,6 +20,18 @@ Hello, world!
 \end{document}`, removeComments(input))
 }
 
+func TestRemoveCommentsPreservesEscapedPercent(t *testing.T) {
+	const input = `accuracy improved by 12\% over baseline % TODO: recheck`
+	assert.Equal(t, `accuracy improved by 12\% over baseline`, removeComments(input))
+}
+
+func TestRemoveCommentsDoubleBackslashBeforePercent(t *testing.T) {
+	const input = `line one \\% this is a real comment after a line break
+next line`
+	assert.Equal(t, `line one \\
+next line`, removeComments(input))
+}
+
 func TestLatexpand(t *testing.T) {
 	input := map[string]string{
 		"main.tex": `