feat: stdpath('run'), /tmp/nvim.user/ #18993

Problem:
- Since c57f6b28d71d #8519, sockets are created in ~/.local/… but XDG
  spec says: "XDG_RUNTIME_DIR: Must be on the local filesystem", which
  implies that XDG_STATE_DIR is potentially non-local.
- Not easy to inspect Nvim-created temp files (for debugging etc).

Solution:
- Store sockets in stdpath('run') ($XDG_RUNTIME_DIR).
- Establish "/tmp/nvim.user/" as the tempdir root shared by all Nvims.
- Make ok() actually useful.
- Introduce assert_nolog().

closes #3517
closes #17093

7 files changed, 101 insertions, 7 deletions

diff --git a/test/functional/api/server_requests_spec.lua b/test/functional/api/server_requests_spec.lua
index cdcf08c348..00a4dd041d 100644
--- a/test/functional/api/server_requests_spec.lua
+++ b/test/functional/api/server_requests_spec.lua
@@ -170,7 +170,7 @@ describe('server -> client', function()
         if method == "notification" then
           eq('done!', eval('rpcrequest('..cid..', "nested")'))
         elseif method == "nested_done" then
-          ok(false, 'this should never have been sent')
+          ok(false, 'never sent', 'sent')
         end
       end
 
diff --git a/test/functional/core/fileio_spec.lua b/test/functional/core/fileio_spec.lua
index bc025771d1..a4d22685e8 100644
--- a/test/functional/core/fileio_spec.lua
+++ b/test/functional/core/fileio_spec.lua
@@ -1,22 +1,28 @@
 local helpers = require('test.functional.helpers')(after_each)
 
+local assert_log = helpers.assert_log
+local assert_nolog = helpers.assert_nolog
 local clear = helpers.clear
 local command = helpers.command
 local eq = helpers.eq
+local ok = helpers.ok
 local feed = helpers.feed
 local funcs = helpers.funcs
 local nvim_prog = helpers.nvim_prog
 local request = helpers.request
 local retry = helpers.retry
 local rmdir = helpers.rmdir
+local matches = helpers.matches
 local mkdir = helpers.mkdir
 local sleep = helpers.sleep
 local read_file = helpers.read_file
+local tmpname = helpers.tmpname
 local trim = helpers.trim
 local currentdir = helpers.funcs.getcwd
 local iswin = helpers.iswin
 local assert_alive = helpers.assert_alive
 local expect_exit = helpers.expect_exit
+local write_file = helpers.write_file
 
 describe('fileio', function()
   before_each(function()
@@ -140,3 +146,69 @@ describe('fileio', function()
   end)
 end)
 
+describe('tmpdir', function()
+  local tmproot_pat = [=[.*[/\\]nvim%.[^/\\]+]=]
+  local testlog = 'Xtest_tmpdir_log'
+  local faketmp
+
+  before_each(function()
+    -- Fake /tmp dir so that we can mess it up.
+    faketmp = tmpname()
+    os.remove(faketmp)
+    mkdir(faketmp)
+  end)
+
+  after_each(function()
+    expect_exit(command, ':qall!')
+    os.remove(testlog)
+  end)
+
+  it('failure modes', function()
+    clear({ env={ NVIM_LOG_FILE=testlog, TMPDIR=faketmp, } })
+    assert_nolog('tempdir is not a directory', testlog)
+    assert_nolog('tempdir has invalid permissions', testlog)
+
+    -- Tempfiles typically look like: "…/nvim.<user>/xxx/0".
+    --  - "…/nvim.<user>/xxx/" is the per-process tmpdir, not shared with other Nvims.
+    --  - "…/nvim.<user>/" is the tmpdir root, shared by all Nvims (normally).
+    local tmproot = (funcs.tempname()):match(tmproot_pat)
+    ok(tmproot:len() > 4, 'tmproot like "nvim.foo"', tmproot)
+
+    -- Test how Nvim handles invalid tmpdir root (by hostile users or accidents).
+    --
+    -- "…/nvim.<user>/" is not a directory:
+    expect_exit(command, ':qall!')
+    rmdir(tmproot)
+    write_file(tmproot, '')  -- Not a directory, vim_mktempdir() should skip it.
+    clear({ env={ NVIM_LOG_FILE=testlog, TMPDIR=faketmp, } })
+    matches(tmproot_pat, funcs.stdpath('run'))  -- Tickle vim_mktempdir().
+    -- Assert that broken tmpdir root was handled.
+    retry(nil, 1000, function()
+      assert_log('tempdir root not a directory', testlog, 100)
+    end)
+
+    -- "…/nvim.<user>/" has wrong permissions:
+    if iswin() then
+      return  -- TODO(justinmk): need setfperm/getfperm on Windows. #8244
+    end
+    os.remove(testlog)
+    os.remove(tmproot)
+    mkdir(tmproot)
+    funcs.setfperm(tmproot, 'rwxr--r--')  -- Invalid permissions, vim_mktempdir() should skip it.
+    clear({ env={ NVIM_LOG_FILE=testlog, TMPDIR=faketmp, } })
+    matches(tmproot_pat, funcs.stdpath('run'))  -- Tickle vim_mktempdir().
+    -- Assert that broken tmpdir root was handled.
+    retry(nil, 1000, function()
+      assert_log('tempdir root has invalid permissions', testlog, 100)
+    end)
+  end)
+
+  it('too long', function()
+    local bigname = ('%s/%s'):format(faketmp, ('x'):rep(666))
+    mkdir(bigname)
+    clear({ env={ NVIM_LOG_FILE=testlog, TMPDIR=bigname, } })
+    matches(tmproot_pat, funcs.stdpath('run'))  -- Tickle vim_mktempdir().
+    local len = (funcs.tempname()):len()
+    ok(len > 4 and len < 256, '4 < len < 256', tostring(len))
+  end)
+end)
diff --git a/test/functional/core/startup_spec.lua b/test/functional/core/startup_spec.lua
index 5ba80a3646..fc9ea72ff2 100644
--- a/test/functional/core/startup_spec.lua
+++ b/test/functional/core/startup_spec.lua
@@ -399,7 +399,8 @@ describe('startup', function()
     eq({'ordinary', 'FANCY', 'mittel', 'FANCY after', 'ordinary after'}, exec_lua [[ return _G.test_loadorder ]])
 
     local rtp = meths.get_option'rtp'
-    ok(startswith(rtp, 'test/functional/fixtures/nvim,test/functional/fixtures/pack/*/start/*,test/functional/fixtures/start/*,test/functional/fixtures,test/functional/fixtures/middle,'), 'rtp='..rtp)
+    ok(startswith(rtp, 'test/functional/fixtures/nvim,test/functional/fixtures/pack/*/start/*,test/functional/fixtures/start/*,test/functional/fixtures,test/functional/fixtures/middle,'),
+      'startswith(…)', 'rtp='..rtp)
   end)
 
   it("handles the correct order with opt packages and after/", function()
diff --git a/test/functional/options/defaults_spec.lua b/test/functional/options/defaults_spec.lua
index 92873e9937..9244ca0974 100644
--- a/test/functional/options/defaults_spec.lua
+++ b/test/functional/options/defaults_spec.lua
@@ -9,6 +9,7 @@ local clear = helpers.clear
 local exc_exec = helpers.exc_exec
 local eval = helpers.eval
 local eq = helpers.eq
+local ok = helpers.ok
 local funcs = helpers.funcs
 local insert = helpers.insert
 local iswin = helpers.iswin
@@ -238,7 +239,7 @@ describe('startup defaults', function()
   end)
 end)
 
-describe('XDG-based defaults', function()
+describe('XDG defaults', function()
   -- Need separate describe() blocks to not run clear() twice.
   -- Do not put before_each() here for the same reasons.
 
@@ -282,6 +283,7 @@ describe('XDG-based defaults', function()
       eq('.', meths.get_option('viewdir'))
       eq('.', meths.get_option('directory'))
       eq('.', meths.get_option('undodir'))
+      ok((funcs.tempname()):len() > 4)
     end)
   end)
 
@@ -306,6 +308,7 @@ describe('XDG-based defaults', function()
                          .. env_sep.. root_path .. ('/b'):rep(2048)
                          .. (env_sep .. root_path .. '/c'):rep(512)),
         XDG_DATA_HOME=(root_path .. ('/X'):rep(4096)),
+        XDG_RUNTIME_DIR=(root_path .. ('/X'):rep(4096)),
         XDG_STATE_HOME=(root_path .. ('/X'):rep(4096)),
         XDG_DATA_DIRS=(root_path .. ('/A'):rep(2048)
                        .. env_sep .. root_path .. ('/B'):rep(2048)
@@ -376,6 +379,7 @@ describe('XDG-based defaults', function()
         XDG_CONFIG_HOME='$XDG_DATA_HOME',
         XDG_CONFIG_DIRS='$XDG_DATA_DIRS',
         XDG_DATA_HOME='$XDG_CONFIG_HOME',
+        XDG_RUNTIME_DIR='$XDG_RUNTIME_DIR',
         XDG_STATE_HOME='$XDG_CONFIG_HOME',
         XDG_DATA_DIRS='$XDG_CONFIG_DIRS',
       }})
@@ -438,6 +442,7 @@ describe('XDG-based defaults', function()
           meths.get_option('undodir'):gsub('\\', '/'))
       eq(('$XDG_CONFIG_HOME/' .. state_dir .. '/view//'),
           meths.get_option('viewdir'):gsub('\\', '/'))
+      eq(nil, (funcs.tempname()):match('XDG_RUNTIME_DIR'))
     end)
   end)
 
@@ -519,6 +524,7 @@ describe('stdpath()', function()
     eq(statedir, funcs.fnamemodify(funcs.stdpath('state'), ':t'))
     eq('table', type(funcs.stdpath('config_dirs')))
     eq('table', type(funcs.stdpath('data_dirs')))
+    eq('string', type(funcs.stdpath('run')))
     assert_alive()  -- Check for crash. #8393
   end)
 
diff --git a/test/functional/terminal/api_spec.lua b/test/functional/terminal/api_spec.lua
index b3a0b8a2c8..5305b8af9c 100644
--- a/test/functional/terminal/api_spec.lua
+++ b/test/functional/terminal/api_spec.lua
@@ -48,8 +48,8 @@ describe('api', function()
       {3:-- TERMINAL --}                                    |
     ]])
 
-    ok(socket_session1:request("nvim_ui_attach", 42, 6, {rgb=true}))
-    ok(socket_session2:request("nvim_ui_attach", 25, 30, {rgb=true}))
+    ok((socket_session1:request("nvim_ui_attach", 42, 6, {rgb=true})))
+    ok((socket_session2:request("nvim_ui_attach", 25, 30, {rgb=true})))
 
     socket_session1:notify("nvim_input", "\n[socket 1] this is more than 25 columns")
     socket_session2:notify("nvim_input", "\n[socket 2] input")
diff --git a/test/functional/vimscript/server_spec.lua b/test/functional/vimscript/server_spec.lua
index ea07be231d..6e95459630 100644
--- a/test/functional/vimscript/server_spec.lua
+++ b/test/functional/vimscript/server_spec.lua
@@ -5,6 +5,7 @@ local iswin = helpers.iswin
 local ok = helpers.ok
 local matches = helpers.matches
 local pcall_err = helpers.pcall_err
+local mkdir = helpers.mkdir
 
 local function clear_serverlist()
   for _, server in pairs(funcs.serverlist()) do
@@ -13,9 +14,19 @@ local function clear_serverlist()
 end
 
 describe('server', function()
-  before_each(clear)
+  it('serverstart() stores sockets in $XDG_RUNTIME_DIR', function()
+    local dir = 'Xtest_xdg_run'
+    mkdir(dir)
+    clear({ env={ XDG_RUNTIME_DIR=dir } })
+    matches(dir, funcs.stdpath('run'))
+    if not iswin() then
+      matches(dir, funcs.serverstart())
+    end
+  end)
+
 
   it('serverstart(), serverstop() does not set $NVIM', function()
+    clear()
     local s = eval('serverstart()')
     assert(s ~= nil and s:len() > 0, "serverstart() returned empty")
     eq('', eval('$NVIM'))
@@ -34,6 +45,7 @@ describe('server', function()
   end)
 
   it('sets v:servername at startup or if all servers were stopped', function()
+    clear()
     local initial_server = meths.get_vvar('servername')
     assert(initial_server ~= nil and initial_server:len() > 0,
            'v:servername was not initialized')
@@ -62,11 +74,13 @@ describe('server', function()
   end)
 
   it('serverstop() returns false for invalid input', function()
+    clear()
     eq(0, eval("serverstop('')"))
     eq(0, eval("serverstop('bogus-socket-name')"))
   end)
 
   it('parses endpoints', function()
+    clear()
     clear_serverlist()
     eq({}, funcs.serverlist())
 
@@ -111,6 +125,7 @@ describe('server', function()
   end)
 
   it('serverlist() returns the list of servers', function()
+    clear()
     -- There should already be at least one server.
     local n = eval('len(serverlist())')
 
diff --git a/test/functional/vimscript/timer_spec.lua b/test/functional/vimscript/timer_spec.lua
index 20f2afb20f..5463cfb234 100644
--- a/test/functional/vimscript/timer_spec.lua
+++ b/test/functional/vimscript/timer_spec.lua
@@ -96,7 +96,7 @@ describe('timers', function()
     nvim_async("command", "let g:val = 0 | let g:c = getchar()")
     retry(nil, nil, function()
       local val = eval("g:val")
-      ok(val >= 2, "expected >= 2, got: "..tostring(val))
+      ok(val >= 2, '>= 2', tostring(val))
       eq(0, eval("getchar(1)"))
     end)
     feed("c")