escape build dir in the output file name pattern

Author: michal-h21

CHANGELOG.md

@@ -1,5 +1,11 @@
 # Changelog
 
+- 2026/05/11
+
+  - added new `mkutils` function, `escape_pattern`
+  - use `escape_pattern` to sanitize output file names
+    https://tex.stackexchange.com/q/762690/2891
+
 - 2026/05/10
 
   - set anchor id in lists to the `<li>` element in the `itemparagraphs` DOM filter.

make4ht

@@ -132,7 +132,7 @@ make:match(".*",function(filename,par)
     return true
   end
   log:info("outdir: "..outdir)
-  local outfilename = filename:gsub("^" .. (par.builddir or ""), "")
+  local outfilename = filename:gsub("^" .. mkutils.escape_pattern(par.builddir or ""), "")
   outfilename = outdir .. outfilename
   mkutils.copy(filename,outfilename)
 	return true

mkutils.lua

@@ -320,6 +320,11 @@ local function run(untrusted_code, env)
   return pcall(untrusted_function)
 end
 
+function escape_pattern(str)
+  -- escape all magic characters in the string, so it can be used as a literal pattern
+  return (str:gsub("([%(%)%.%%%+%-%*%?%[%]%^%$])", "%%%1"))
+end
+
 local main_settings = {}
 main_settings.fonts = {}
 -- use global environment in the build file