Use uv_os_homedir and current directory as backup when $HOME is not set (#13657)

Close https://github.com/neovim/neovim/issues/8614

Use uv_os_homedir and current directory as backup if HOME env is not set.
Allocate homedir only if var is not NULL.

1 files changed, 61 insertions, 0 deletions

diff --git a/test/functional/eval/environ_spec.lua b/test/functional/eval/environ_spec.lua
index 54d2dc960b..9e19568249 100644
--- a/test/functional/eval/environ_spec.lua
+++ b/test/functional/eval/environ_spec.lua
@@ -3,6 +3,11 @@ local clear = helpers.clear
 local eq = helpers.eq
 local environ = helpers.funcs.environ
 local exists = helpers.funcs.exists
+local system = helpers.funcs.system
+local nvim_prog = helpers.nvim_prog
+local command = helpers.command
+local eval = helpers.eval
+local setenv = helpers.funcs.setenv
 
 describe('environment variables', function()
   it('environ() handles empty env variable', function()
@@ -17,3 +22,59 @@ describe('environment variables', function()
     eq(0, exists('$DOES_NOT_EXIST'))
   end)
 end)
+
+describe('empty $HOME', function()
+  local original_home = os.getenv('HOME')
+
+  -- recover $HOME after each test
+  after_each(function()
+    if original_home ~= nil then
+      setenv('HOME', original_home)
+    end
+    os.remove('test_empty_home')
+    os.remove('./~')
+  end)
+
+  local function tilde_in_cwd()
+    -- get files in cwd
+    command("let test_empty_home_cwd_files = split(globpath('.', '*'), '\n')")
+    -- get the index of the file named '~'
+    command('let test_empty_home_tilde_index = index(test_empty_home_cwd_files, "./~")')
+    return eval('test_empty_home_tilde_index') ~= -1
+  end
+
+  local function write_and_test_tilde()
+    system({nvim_prog, '-u', 'NONE', '-i', 'NONE', '--headless',
+                                          '-c', 'write test_empty_home', '+q'})
+    eq(false, tilde_in_cwd())
+  end
+
+  it("'~' folder not created in cwd if $HOME and related env not defined", function()
+    command("unlet $HOME")
+    write_and_test_tilde()
+
+    command("let $HOMEDRIVE='C:'")
+    command("let $USERPROFILE='C:\\'")
+    write_and_test_tilde()
+
+    command("unlet $HOMEDRIVE")
+    write_and_test_tilde()
+
+    command("unlet $USERPROFILE")
+    write_and_test_tilde()
+
+    command("let $HOME='%USERPROFILE%'")
+    command("let $USERPROFILE='C:\\'")
+    write_and_test_tilde()
+  end)
+
+  it("'~' folder not created in cwd if writing a file with invalid $HOME", function()
+    setenv('HOME', '/path/does/not/exist')
+    write_and_test_tilde()
+  end)
+
+  it("'~' folder not created in cwd if writing a file with $HOME=''", function()
+    command("let $HOME=''")
+    write_and_test_tilde()
+  end)
+end)