Fix type of various `sessionVariables` options

Unfortunately, using `attrsOf` is not possible since it results in too
eager evaluation. In particular, the

    home.sessionVariables = {
      FOO = "Hello";
      BAR = "${config.home.sessionVariables.FOO} World!";
    };

example will cause an infinite recursion.

This commit restores the option type of

- `home.sessionVariables`,
- `pam.sessionVariables`,
- `programs.bash.sessionVariables`, and
- `programs.zsh.sessionVariables`

to `attrs`. It also adds test cases for the above options to avoid
regressions.

Fixes #659

1 files changed, 22 insertions, 0 deletions

diff --git a/tests/modules/programs/zsh/session-variables.nix b/tests/modules/programs/zsh/session-variables.nix
new file mode 100644
index 00000000000..a87d39820cf
--- /dev/null
+++ b/tests/modules/programs/zsh/session-variables.nix
@@ -0,0 +1,22 @@
+{ config, lib, ... }:
+
+with lib;
+
+{
+  config = {
+    programs.zsh = {
+      enable = true;
+
+      sessionVariables = {
+        V1 = "v1";
+        V2 = "v2-${config.programs.zsh.sessionVariables.V1}";
+      };
+    };
+
+    nmt.script = ''
+      assertFileExists home-files/.zshrc
+      assertFileRegex home-files/.zshrc 'export V1="v1"'
+      assertFileRegex home-files/.zshrc 'export V2="v2-v1"'
+    '';
+  };
+}