plugin/shada: Handle NUL characters with intchar correctly

Fixes #5482

2 files changed, 38 insertions, 12 deletions

diff --git a/runtime/autoload/shada.vim b/runtime/autoload/shada.vim
index 9be85b6f2e..cf27ee608a 100644
--- a/runtime/autoload/shada.vim
+++ b/runtime/autoload/shada.vim
@@ -241,8 +241,6 @@ function s:shada_check_type(type, val) abort
     if msg isnot# 0
       return msg
     endif
-    if a:val > 0 || a:val < 1
-    endif
     return 0
   elseif a:type is# 'binarray'
     if type isnot# 'array'
@@ -359,9 +357,14 @@ function s:shada_string(type, v) abort
   if (has_key(s:SHADA_ENUMS, a:type) && type(a:v) == type(0)
      \&& has_key(s:SHADA_REV_ENUMS[a:type], a:v))
     return s:SHADA_REV_ENUMS[a:type][a:v]
-  elseif (a:type is# 'intchar' && type(a:v) == type(0)
-         \&& strtrans(nr2char(a:v)) is# nr2char(a:v))
-    return "'" . nr2char(a:v) . "'"
+  " Restricting a:v to be <= 127 is not necessary, but intchar constants are
+  " normally expected to be either ASCII printable characters or NUL.
+  elseif a:type is# 'intchar' && type(a:v) == type(0) && a:v >= 0 && a:v <= 127
+    if a:v > 0 && strtrans(nr2char(a:v)) is# nr2char(a:v)
+      return "'" . nr2char(a:v) . "'"
+    else
+      return "'\\" . a:v . "'"
+    endif
   else
     return msgpack#string(a:v)
   endif
diff --git a/test/functional/plugin/shada_spec.lua b/test/functional/plugin/shada_spec.lua
index b1209a22e9..b543037ae2 100644
--- a/test/functional/plugin/shada_spec.lua
+++ b/test/functional/plugin/shada_spec.lua
@@ -609,6 +609,18 @@ describe('In autoload/shada.vim', function()
         'abc',
         -1,
       ]}] ]]):gsub('\n', ''))
+      -- Regression: NUL separator must be properly supported
+      sd2strings_eq({
+        'History entry with timestamp ' .. epoch .. ':',
+        '  @ Description_  Value',
+        '  - history type  SEARCH',
+        '  - contents      ""',
+        '  - separator     \'\\0\'',
+      }, ([[ [{'type': 4, 'timestamp': 0, 'data': [
+        1,
+        '',
+        0x0
+      ]}] ]]):gsub('\n', ''))
     end)
 
     it('works with register items', function()
@@ -837,7 +849,7 @@ describe('In autoload/shada.vim', function()
       sd2strings_eq({
         'Global mark with timestamp ' .. epoch .. ':',
         '  % Key  Description  Value',
-        '  + n    name         20',
+        '  + n    name         \'\\20\'',
         '  + f    file name    "foo"',
         '  # Value is negative',
         '  + l    line number  -10',
@@ -852,7 +864,18 @@ describe('In autoload/shada.vim', function()
       sd2strings_eq({
         'Global mark with timestamp ' .. epoch .. ':',
         '  % Key  Description  Value',
-        '  + n    name         20',
+        '  + n    name         128',
+        '  + f    file name    "foo"',
+        '  + l    line number  1',
+        '  + c    column       0',
+      }, ([[ [{'type': 7, 'timestamp': 0, 'data': {
+        'n': 128,
+        'f': 'foo',
+      }}] ]]):gsub('\n', ''))
+      sd2strings_eq({
+        'Global mark with timestamp ' .. epoch .. ':',
+        '  % Key  Description  Value',
+        '  + n    name         \'\\20\'',
         '  + f    file name    "foo"',
         '  # Expected integer',
         '  + l    line number  "FOO"',
@@ -1123,7 +1146,7 @@ describe('In autoload/shada.vim', function()
         'Local mark with timestamp ' .. epoch .. ':',
         '  % Key  Description  Value',
         '  + f    file name    "foo"',
-        '  + n    name         20',
+        '  + n    name         \'\\20\'',
         '  # Value is negative',
         '  + l    line number  -10',
         '  # Value is negative',
@@ -1138,7 +1161,7 @@ describe('In autoload/shada.vim', function()
         'Local mark with timestamp ' .. epoch .. ':',
         '  % Key  Description  Value',
         '  + f    file name    "foo"',
-        '  + n    name         20',
+        '  + n    name         \'\\20\'',
         '  # Expected integer',
         '  + l    line number  "FOO"',
         '  # Expected integer',
@@ -1932,13 +1955,13 @@ describe('In autoload/shada.vim', function()
         'Buffer list with timestamp ' .. epoch .. ':',
         '  % Key  Description  Value',
         '  # Expected binary string',
-        '  + f    file name    10',
+        '  + f    file name    \'\\10\'',
         '  + l    line number  1',
         '  + c    column       0',
         '',
         '  % Key  Description  Value',
         '  # Expected binary string',
-        '  + f    file name    20',
+        '  + f    file name    \'\\20\'',
         '  + l    line number  1',
         '  + c    column       0',
       })
@@ -1948,7 +1971,7 @@ describe('In autoload/shada.vim', function()
         'Buffer list with timestamp ' .. epoch .. ':',
         '  % Key  Description  Value',
         '  # Expected binary string',
-        '  + f    file name    10',
+        '  + f    file name    \'\\10\'',
         '  + l    line number  1',
         '  + c    column       0',
         '',