fix(events): make v:event readonly in more events (#18070)

This makes v:event readonly in these four events:
- ChanInfo
- ChanOpen
- RecordingLeave
- TermClose

1 files changed, 32 insertions, 0 deletions

diff --git a/test/functional/autocmd/autocmd_spec.lua b/test/functional/autocmd/autocmd_spec.lua
index c010fb8034..6111654b5e 100644
--- a/test/functional/autocmd/autocmd_spec.lua
+++ b/test/functional/autocmd/autocmd_spec.lua
@@ -17,6 +17,7 @@ local command = helpers.command
 local exc_exec = helpers.exc_exec
 local exec_lua = helpers.exec_lua
 local curbufmeths = helpers.curbufmeths
+local retry = helpers.retry
 local source = helpers.source
 
 describe('autocmd', function()
@@ -439,6 +440,37 @@ describe('autocmd', function()
     ]]}
   end)
 
+  describe('v:event is readonly #18063', function()
+    it('during ChanOpen event', function()
+      command('autocmd ChanOpen * let v:event.info.id = 0')
+      funcs.jobstart({'cat'})
+      retry(nil, nil, function()
+        eq('E46: Cannot change read-only variable "v:event.info"', meths.get_vvar('errmsg'))
+      end)
+    end)
+
+    it('during ChanOpen event', function()
+      command('autocmd ChanInfo * let v:event.info.id = 0')
+      meths.set_client_info('foo', {}, 'remote', {}, {})
+      retry(nil, nil, function()
+        eq('E46: Cannot change read-only variable "v:event.info"', meths.get_vvar('errmsg'))
+      end)
+    end)
+
+    it('during RecordingLeave event', function()
+      command([[autocmd RecordingLeave * let v:event.regname = '']])
+      eq('Vim(let):E46: Cannot change read-only variable "v:event.regname"',
+         pcall_err(command, 'normal! qqq'))
+    end)
+
+    it('during TermClose event', function()
+      command('autocmd TermClose * let v:event.status = 0')
+      command('terminal')
+      eq('Vim(let):E46: Cannot change read-only variable "v:event.status"',
+         pcall_err(command, 'bdelete!'))
+    end)
+  end)
+
   describe('old_tests', function()
     it('vimscript: WinNew ++once', function()
       source [[