From 33464189bc02b2555e26dc4e9f7b3fbbcdd02490 Mon Sep 17 00:00:00 2001
From: Gregory Anders <8965202+gpanders@users.noreply.github.com>
Date: Sat, 17 Aug 2024 22:28:03 -0500
Subject: [PATCH] fix(vim.text): handle very long strings (#30075)

Lua's string.byte has a maximum (undocumented) allowable length, so
vim.text.hencode fails on large strings with the error "string slice too
long".

Instead of converting the string to an array of bytes up front, convert
each character to a byte one at a time.
---
 runtime/lua/vim/text.lua          | 5 ++---
 test/functional/lua/text_spec.lua | 6 ++++++
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/runtime/lua/vim/text.lua b/runtime/lua/vim/text.lua
index 0be3396464..d45c8021c6 100644
--- a/runtime/lua/vim/text.lua
+++ b/runtime/lua/vim/text.lua
@@ -7,10 +7,9 @@ local M = {}
 --- @param str string String to encode
 --- @return string : Hex encoded string
 function M.hexencode(str)
-  local bytes = { str:byte(1, #str) }
   local enc = {} ---@type string[]
-  for i = 1, #bytes do
-    enc[i] = string.format('%02X', bytes[i])
+  for i = 1, #str do
+    enc[i] = string.format('%02X', str:byte(i, i + 1))
   end
   return table.concat(enc)
 end
diff --git a/test/functional/lua/text_spec.lua b/test/functional/lua/text_spec.lua
index 9e77953c8c..be471bfd62 100644
--- a/test/functional/lua/text_spec.lua
+++ b/test/functional/lua/text_spec.lua
@@ -20,5 +20,11 @@ describe('vim.text', function()
         eq(input, vim.text.hexdecode(output))
       end
     end)
+
+    it('works with very large strings', function()
+      local input, output = string.rep('😂', 2 ^ 16), string.rep('F09F9882', 2 ^ 16)
+      eq(output, vim.text.hexencode(input))
+      eq(input, vim.text.hexdecode(output))
+    end)
   end)
 end)