factor out ENSURE-HOST & call it in hostattrs accessors

Signed-off-by: Sean Whitton <spwhitton@spwhitton.name>

6 files changed, 19 insertions, 5 deletions

diff --git a/doc/hosts.rst b/doc/hosts.rst
index af5104b..1f8a56c 100644
--- a/doc/hosts.rst
+++ b/doc/hosts.rst
@@ -37,3 +37,11 @@ keyword symbols.  The semantics of these attributes are documented here:
 
 - ``:APT.MIRROR``: for hosts running Debian or a Debian derivative, the host's
   preferred apt mirror
+
+Host designators
+----------------
+
+A string designates a host with that hostname and no properties.  Using
+strings to designate hosts is not valid in all contexts -- some macros and
+properties where it might be useful to pass a string instead of a ``HOST``
+object call ``ENSURE-HOST`` to convert, but this is not done everywhere.
diff --git a/src/deployment.lisp b/src/deployment.lisp
index 226c55d..8f95f3f 100644
--- a/src/deployment.lisp
+++ b/src/deployment.lisp
@@ -156,9 +156,7 @@ The evaluation of PROPERTIES to produce a property application specification
 may retrieve existing hostattrs, but should not set any new ones (not to be
 confused with how the :HOSTATTRS subroutines of properties in PROPERTIES may
 set additional hostattrs)."
-  (once-only ((host (if (stringp host)
-                        `(make-host :hostattrs (list :hostname (list ,host)))
-                        host)))
+  (once-only ((host `(ensure-host ,host)))
     `(deploy-these* ',connections
                     ,host
                     (let ((*host* (shallow-copy-host ,host)))
diff --git a/src/host.lisp b/src/host.lisp
index a449d3c..50155c8 100644
--- a/src/host.lisp
+++ b/src/host.lisp
@@ -49,6 +49,13 @@
   (:documentation
    "A host whose :PREPROCESS and :HOSTATTRS subroutines have not been run."))
 
+(defgeneric ensure-host (host)
+  (:documentation "Return the HOST value designated by HOST.")
+  (:method ((host host))
+    host)
+  (:method ((hostname string))
+    (make-host :hostattrs `(:hostname (,hostname)))))
+
 (defmethod shallow-copy-host ((host host))
   (make-instance (type-of host)
                  :hostattrs (copy-list (hostattrs host))
diff --git a/src/package.lisp b/src/package.lisp
index 417267e..90f5608 100644
--- a/src/package.lisp
+++ b/src/package.lisp
@@ -192,6 +192,7 @@
            #:hostattrs
            #:host-propspec
            #:preprocess-host
+           #:ensure-host
            #:with-preserve-hostattrs
            #:with-replace-hostattrs
 
diff --git a/src/property.lisp b/src/property.lisp
index c3a6a5d..9fe0c72 100644
--- a/src/property.lisp
+++ b/src/property.lisp
@@ -453,7 +453,7 @@ other than constant values and propapps to property combinators."
 this property cannot be applied to this host.  E.g. the property will try to
 install an apt package but the host is FreeBSD.")
 
-(defun get-hostattrs (k &optional (host *host*))
+(defun get-hostattrs (k &optional (host *host*) &aux (host (ensure-host host)))
   "Retrieve the list of static informational attributes of type KEY.
 
 Called by property :HOSTATTRS, :APPLY and :UNAPPLY subroutines."
diff --git a/src/propspec.lisp b/src/propspec.lisp
index e4e8832..92a73e8 100644
--- a/src/propspec.lisp
+++ b/src/propspec.lisp
@@ -207,7 +207,7 @@ PRINT-OBJECT."))
   "Convert a property application specification expression into a property
 application specification proper by associating it with a list of ASDF
 systems."
-  (if systems-supplied-p
+  (if (or systems-supplied-p (not propspec))
       (make-instance 'unpreprocessed-propspec
                      :systems systems :propspec propspec)
       (make-instance 'unpreprocessed-propspec :propspec propspec)))