refactor: Windows tilde expansion followup (#29380)

Followup to #28515:

Rename the static os_homedir() to os_uv_homedir() to emphasize that it
is a wrapper around a libuv function.

Add the function os_get_homedir() to os/env.c to return the cached
homedir value as a const. Must be called after homedir is initialized or
it fails.

The difference between this function and the static os_uv_homedir() is
that the latter gets the homedir from libuv and is used to initialize
homedir in init_homedir(), while os_get_homedir() just returns homedir
as a const if it's initialized and is public.

Use the os_get_homedir() accessor for ~/ expansion on Windows to make
the code more concise.

Add a Windows section to main_spec.lua with tests for expanding ~/ and
~\ prefixes for files passed in on the command-line.

Signed-off-by: Rafael Kitover <rkitover@gmail.com>

1 files changed, 2 insertions, 4 deletions

diff --git a/src/nvim/main.c b/src/nvim/main.c
index 5e243df975..57909b14ef 100644
--- a/src/nvim/main.c
+++ b/src/nvim/main.c
@@ -1437,12 +1437,10 @@ scripterror:
       // On Windows expand "~\" or "~/" prefix in file names to profile directory.
 #ifdef MSWIN
       if (*p == '~' && (p[1] == '\\' || p[1] == '/')) {
-        char *profile_dir = vim_getenv("HOME");
-        size_t size = strlen(profile_dir) + strlen(p);
+        size_t size = strlen(os_get_homedir()) + strlen(p);
         char *tilde_expanded = xmalloc(size);
-        snprintf(tilde_expanded, size, "%s%s", profile_dir, p + 1);
+        snprintf(tilde_expanded, size, "%s%s", os_get_homedir(), p + 1);
         xfree(p);
-        xfree(profile_dir);
         p = tilde_expanded;
       }
 #endif