zshenv: clarify some comments

diff --git a/etc/zsh/.zshenv b/etc/zsh/.zshenv
index 3c53c99250383ba3105e1b2e51636e684cd66c66..bf8af5662fc0c89e6fb4714954696b4c33406cfb 100644 (file)
--- a/etc/zsh/.zshenv
+++ b/etc/zsh/.zshenv
@@ -127,14 +127,17 @@ if [[ ! -v _sev_setup_path || -o login ]] {
     # NOTE: do not set _sev_setup_path, it is set in zprofile
 }
 
-### home dir setup & exports
+### home dir setup & additional exports
 # XXX: traditionally, zshenv should just contain exports, and not touch the
-#      filesystem. however, some system profile scripts that are sourced in the
-#      system zprofile may attempt to do things that rely on some of these
-#      vars. for example, `flatpak-bindir.sh` in the Arch Linux flatpak package
-#      references $XDG_DATA_HOME with no fallback. since we do special handling
-#      for these vars before we export them, we're forced to do it all here
-#      instead of zprofile.
+#      filesystem. however, our TMPDIR and XDG vars rely on mutable user paths
+#      that may not exist, and as such need to be set up before the rest of the
+#      system can use them. this is important as some environments include code
+#      in the global zprofile, or source scripts of other shells in the global
+#      zprofile, that may rely on our desired dir structure and vars pointing
+#      to it. for example, `flatpak-bindir.sh` in the Arch Linux flatpak
+#      package references $XDG_DATA_HOME with no fallback. since we do special
+#      handling for these vars before we export them, we're forced to do it all
+#      here instead of at the top of the zprofile.
 
 ## xdg local dir
 # NOTE: need this for tmp, so confirm it exists.
@@ -152,7 +155,8 @@ if [[ ! -v _sev_setup_path || -o login ]] {
 #       though it is not expressly spec compliant. this may also cause problems
 #       with disowned applications that still try to use the directories after
 #       the toplevel shell has already logged out and the dirs removed, but the
-#       chances of that are slim.
+#       chances of that are slim. this also needs to be adjusted for usermode
+#       Xorg, as it requires $PREFIX/tmp/.X11-unix on most installs.
 if [[ ! -v _sev_tmp ]] {
     _sev_tmp=~/.local/tmp
     # create personal TMPDIR under system tmp