Before: function! TestCallback(buffer, output) return [ \ { \ 'lnum': 1, \ 'bufnr': 1, \ 'vcol': 0, \ 'linter_name': 'testlinter', \ 'nr': -1, \ 'type': 'E', \ 'col': 1, \ 'text': 'Test Error', \ }, \] endfunction call ale#linter#Define('foobar', { \ 'name': 'testlinter', \ 'callback': 'TestCallback', \ 'executable': 'echo', \ 'command': 'echo', \}) let g:ale_buffer_info = {} After: unlet! b:in_sandbox unlet! b:result delfunction TestCallback call ale#linter#Reset() let g:ale_buffer_info = {} Given foobar (Some imaginary filetype): foo bar baz Execute(ale#util#InSandbox should return 1 when in a sandbox): sandbox let b:in_sandbox = ale#util#InSandbox() Assert b:in_sandbox, 'ale#util#InSandbox() returned 0 for a sandbox command' Execute(ALE shouldn't blow up when run from a sandbox): AssertEqual 'foobar', &filetype sandbox call ale#Queue(0) sandbox call ale#Queue(1) Execute(ALE shouldn't blow up if file cleanup happens in a sandbox): " Make a call to an engine function first, so the function will be defined " before we make the sandbox call. " " You are not allowed to define any functions in the sandbox. call ale#engine#InitBufferInfo(3) let g:ale_buffer_info[3] = { \ 'temporary_file_list': ['/tmp/foo'], \ 'temporary_directory_list': ['/tmp/bar'], \} sandbox call ale#command#RemoveManagedFiles(3) AssertEqual ['/tmp/foo'], g:ale_buffer_info[3].temporary_file_list AssertEqual ['/tmp/bar'], g:ale_buffer_info[3].temporary_directory_list Execute(You shouldn't be able to define linters from the sandbox): call ale#linter#Reset() call ale#linter#PreventLoading('testft') AssertThrows sandbox call ale#linter#Define('testft', { \ 'name': 'testlinter', \ 'output_stream': 'stdout', \ 'executable': 'testlinter', \ 'command': 'testlinter', \ 'callback': 'testCB', \}) AssertEqual 'Vim(let):E48: Not allowed in sandbox', g:vader_exception AssertEqual [], ale#linter#GetAll(['testft']) Execute(You shouldn't be able to register fixers from the sandbox): call ale#fix#registry#Clear() AssertThrows sandbox call ale#fix#registry#Add('prettier', '', ['javascript'], 'prettier') AssertEqual 'Vim(let):E48: Not allowed in sandbox', g:vader_exception AssertEqual [], ale#fix#registry#CompleteFixers('', 'ALEFix ', 7) Execute(You shouldn't be able to get linters from the sandbox, to prevent tampering): AssertThrows sandbox call ale#linter#GetLintersLoaded() AssertEqual 'Vim(let):E48: Not allowed in sandbox', g:vader_exception call ale#linter#Reset() sandbox let b:result = ale#linter#GetAll(['testft']) AssertEqual 0, len(b:result) let b:result = ale#linter#GetAll(['testft']) AssertEqual 1, len(b:result) sandbox let b:result = ale#linter#GetAll(['testft']) AssertEqual 0, len(b:result)