set: Print an error when setting `umask` to a bad value

Repurpose the ENV_INVALID return value for env_set(), which wasn't
currently used by anything. When a bad value is passed for the 'umask'
key, return ENV_INVALID to signal this and print a good error message
from the `set` builtin.

This makes `set umask foo` properly produce an error.

1 files changed, 1 insertions, 1 deletions

diff --git a/env.h b/env.h
index 7afa9b9c..8d4a41a9 100644
--- a/env.h
+++ b/env.h
@@ -80,7 +80,7 @@ void env_init(const struct config_paths_t *paths = NULL);
 
    * ENV_PERM, can only be returned when setting as a user, e.g. ENV_USER is set. This means that the user tried to change a read-only variable.
    * ENV_SCOPE, the variable cannot be set in the given scope. This applies to readonly/electric variables set from the local or universal scopes, or set as exported.
-   * ENV_INVALID, the variable name or mode was invalid
+   * ENV_INVALID, the variable value was invalid. This applies only to special variables.
 */
 
 int env_set(const wcstring &key, const wchar_t *val, env_mode_flags_t mode);