fix #2360: don't resolve <<label>> references when label is not f…

…ound in the document

DESCRIPTION

@@ -1,7 +1,7 @@
 Package: knitr
 Type: Package
 Title: A General-Purpose Package for Dynamic Report Generation in R
-Version: 1.48.1
+Version: 1.48.2
 Authors@R: c(
     person("Yihui", "Xie", role = c("aut", "cre"), email = "[email protected]", comment = c(ORCID = "0000-0003-0645-5666")),
     person("Abhraneel", "Sarma", role = "ctb"),

NEWS.md

@@ -1,5 +1,8 @@
 # CHANGES IN knitr VERSION 1.49
 
+## BUG FIXES
+
+- In-chunk references of the form `<<label>>` should not be resolved if `label` is not found in the document (thanks, @jennybc @gadenbuie, #2360).
 
 # CHANGES IN knitr VERSION 1.48
 

R/parser.R

@@ -399,12 +399,13 @@ strip_white = function(x, test_strip = is_blank) {
 parse_chunk = function(x, rc = knit_patterns$get('ref.chunk')) {
   if (length(x) == 0L) return(x)
   x = c(x)  # drop attributes of code (e.g. chunk_opts)
-  if (!group_pattern(rc) || !any(idx <- grepl(rc, x))) return(x)
+  if (!group_pattern(rc) || length(idx <- grep(rc, x)) == 0) return(x)
 
   labels = sub(rc, '\\1', x[idx])
-  code = knit_code$get(labels)
+  code = knit_code$get()
+  i = labels %in% names(code)
+  idx = idx[i]; code = code[labels[i]]
   indent = gsub('^(\\s*).*', '\\1', x[idx])
-  if (length(labels) <= 1L) code = list(code)
   code = mapply(indent_block, code, indent, SIMPLIFY = FALSE, USE.NAMES = FALSE)
 
   x = as.list(x)

tests/testit/test-parser.R

@@ -65,6 +65,11 @@ assert('parse_chunk() preserves indentation', {
   (pc('<<d>>') %==% c('function() {', '  if (T)', '    1+1', '}'))
 })
 
+assert('parse_chunk() ignores labels not found in knit_code', {
+  # chunk 'e' doesn't exist
+  (pc(c('3*3', '<<a>>', '  <<e>>', '<<b>>  ')) %==% c("3*3", "1+1", "  <<e>>", "2-2"))
+})
+
 knit_code$restore()
 
 # duplication of labels