fix(glob): avoid `subcapture nesting too deep` error (#29520)

Use Cmt to evaluate Cond and Elem during match to avoid building the
nested capture structure later.

2 files changed, 28 insertions, 6 deletions

diff --git a/runtime/lua/vim/glob.lua b/runtime/lua/vim/glob.lua
index 6de2bc3e94..22073b15c8 100644
--- a/runtime/lua/vim/glob.lua
+++ b/runtime/lua/vim/glob.lua
@@ -1,6 +1,6 @@
 local lpeg = vim.lpeg
 local P, S, V, R, B = lpeg.P, lpeg.S, lpeg.V, lpeg.R, lpeg.B
-local C, Cc, Ct, Cf = lpeg.C, lpeg.Cc, lpeg.Ct, lpeg.Cf
+local C, Cc, Ct, Cf, Cmt = lpeg.C, lpeg.Cc, lpeg.Ct, lpeg.Cf, lpeg.Cmt
 
 local M = {}
 
@@ -47,13 +47,22 @@ function M.to_lpeg(pattern)
     return (-after * P(1)) ^ 0 * after
   end
 
+  -- luacheck: push ignore s
+  local function cut(s, idx, match)
+    return idx, match
+  end
+  -- luacheck: pop
+
   local p = P({
     'Pattern',
     Pattern = V('Elem') ^ -1 * V('End'),
-    Elem = Cf(
-      (V('DStar') + V('Star') + V('Ques') + V('Class') + V('CondList') + V('Literal'))
-        * (V('Elem') + V('End')),
-      mul
+    Elem = Cmt(
+      Cf(
+        (V('DStar') + V('Star') + V('Ques') + V('Class') + V('CondList') + V('Literal'))
+          * (V('Elem') + V('End')),
+        mul
+      ),
+      cut
     ),
     DStar = (B(pathsep) + -B(P(1)))
       * P('**')
@@ -72,7 +81,7 @@ function M.to_lpeg(pattern)
     -- pattern" which in all other cases is the entire succeeding part of the pattern, but at the end of a {}
     -- condition means "everything after the {}" where several other options separated by ',' may
     -- exist in between that should not be matched by '*'.
-    Cond = Cf((V('Ques') + V('Class') + V('Literal') - S(',}')) ^ 1, mul) + Cc(P(0)),
+    Cond = Cmt(Cf((V('Ques') + V('Class') + V('Literal') - S(',}')) ^ 1, mul), cut) + Cc(P(0)),
     Literal = P(1) / P,
     End = P(-1) * Cc(P(-1)),
   })
diff --git a/test/functional/lua/glob_spec.lua b/test/functional/lua/glob_spec.lua
index b3e1b79ee7..b95d874bb5 100644
--- a/test/functional/lua/glob_spec.lua
+++ b/test/functional/lua/glob_spec.lua
@@ -205,6 +205,19 @@ describe('glob', function()
       eq(true, match('[!a-zA-Z0-9]', '!'))
     end)
 
+    it('should handle long patterns', function()
+      -- lpeg has a recursion limit of 200 by default, make sure the grammar does trigger it on
+      -- strings longer than that
+      local fill_200 =
+        'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa'
+      eq(200, fill_200:len())
+      local long_lit = fill_200 .. 'a'
+      eq(false, match(long_lit, 'b'))
+      eq(true, match(long_lit, long_lit))
+      local long_pat = fill_200 .. 'a/**/*.c'
+      eq(true, match(long_pat, fill_200 .. 'a/b/c/d.c'))
+    end)
+
     it('should match complex patterns', function()
       eq(false, match('**/*.{c,h}', ''))
       eq(false, match('**/*.{c,h}', 'c'))