shada: When using shada-r normalize option path

runtime/doc/options.txt

@@ -5374,8 +5374,7 @@ A jump table for the options with a short description can be found at |Q_op|.
 		specifies the start of a path for which no marks will be
 		stored.  This is to avoid removable media.  For MS-DOS you
 		could use "ra:,rb:".  You can also use it for temp files,
-		e.g., for Unix: "r/tmp".  Case is ignored.  Maximum length of
+		e.g., for Unix: "r/tmp".  Case is ignored.
-		each 'r' argument is 50 characters.
 							*shada-s*
 	s	Maximum size of an item contents in KiB.  If zero then nothing 
 		is saved.  Unlike Vim this applies to all items, except for 

src/nvim/shada.c

@@ -68,6 +68,8 @@ KHASH_SET_INIT_STR(strset)
 #define emsgu(a, ...) emsgu((char_u *) a, __VA_ARGS__)
 #define home_replace_save(a, b) \
     ((char *)home_replace_save(a, (char_u *)b))
+#define home_replace(a, b, c, d, e) \
+    home_replace(a, (char_u *)b, (char_u *)c, d, e)
 #define vim_rename(a, b) \
     (vim_rename((char_u *)a, (char_u *)b))
 #define has_non_ascii(a) (has_non_ascii((char_u *)a))
@@ -4003,16 +4005,16 @@ bool shada_removable(const char *name)
   FUNC_ATTR_WARN_UNUSED_RESULT FUNC_ATTR_PURE
 {
   char  *p;
-  char part[51];
+  char part[MAXPATHL + 1];
   bool retval = false;
-  size_t n;
 
   char *new_name = home_replace_save(NULL, name);
   for (p = (char *) p_shada; *p; ) {
-    (void) copy_option_part(&p, part, 51, ", ");
+    (void) copy_option_part(&p, part, ARRAY_SIZE(part), ", ");
     if (part[0] == 'r') {
-      n = STRLEN(part + 1);
+      home_replace(NULL, part + 1, NameBuff, MAXPATHL, true);
-      if (STRNICMP(part + 1, new_name, n) == 0) {
+      size_t n = STRLEN(NameBuff);
+      if (STRNICMP(NameBuff, new_name, n) == 0) {
         retval = true;
         break;
       }

test/config/paths.lua.in

@@ -7,6 +7,7 @@ end
 
 module.test_include_path = "${CMAKE_BINARY_DIR}/test/includes/post"
 module.test_libnvim_path = "${TEST_LIBNVIM_PATH}"
+module.test_source_path = "${CMAKE_SOURCE_DIR}"
 table.insert(module.include_paths, "${CMAKE_BINARY_DIR}/include")
 
 return module

test/functional/shada/shada_spec.lua

@@ -7,6 +7,7 @@ local write_file, spawn, set_session, nvim_prog, exc_exec =
   helpers.write_file, helpers.spawn, helpers.set_session, helpers.nvim_prog,
   helpers.exc_exec
 local lfs = require('lfs')
+local paths = require('test.config.paths')
 
 local msgpack = require('MessagePack')
 
@@ -146,4 +147,42 @@ describe('ShaDa support code', function()
     session:exit(0)
     os.remove('NONE')
   end)
+
+  it('correctly uses shada-r option', function()
+    nvim('set_var', '__home', paths.test_source_path)
+    nvim_command('let $HOME = __home')
+    nvim_command('unlet __home')
+    nvim_command('edit ~/README.md')
+    nvim_command('normal! GmAggmaAabc')
+    nvim_command('undo')
+    nvim_command('set shada+=%')
+    nvim_command('wshada! ' .. shada_fname)
+    local marklike = {[7]=true, [8]=true, [10]=true, [11]=true}
+    local readme_fname = paths.test_source_path .. '/README.md'
+    local find_readme = function()
+      local found = {}
+      for _, v in ipairs(read_shada_file(shada_fname)) do
+        if marklike[v.type] and v.value.f == readme_fname then
+          found[v.type] = (found[v.type] or 0) + 1
+        elseif v.type == 9 then
+          for _, b in ipairs(v.value) do
+            if b.f == readme_fname then
+              found[v.type] = (found[v.type] or 0) + 1
+            end
+          end
+        end
+      end
+      return found
+    end
+    eq({[7]=1, [8]=2, [9]=1, [10]=4, [11]=1}, find_readme())
+    nvim_command('set shada+=r~')
+    nvim_command('wshada! ' .. shada_fname)
+    eq({}, find_readme())
+    nvim_command('set shada-=r~')
+    nvim_command('wshada! ' .. shada_fname)
+    eq({[7]=1, [8]=2, [9]=1, [10]=4, [11]=1}, find_readme())
+    nvim_command('set shada+=r' .. paths.test_source_path)
+    nvim_command('wshada! ' .. shada_fname)
+    eq({}, find_readme())
+  end)
 end)