[bug#46776] [PATCH] inferior: Extend cached-channel-instance scope.

[Mathieu Othacehe <othacehe@gnu.org>]

* guix/inferior.scm (cached-channel-instance): Turn channels argument into
channels-or-instances.  Adapt the rest of the procedure.
---
 guix/inferior.scm | 31 ++++++++++++++++++++++---------
 1 file changed, 22 insertions(+), 9 deletions(-)

diff --git a/guix/inferior.scm b/guix/inferior.scm
index 0990696e6c..06a187b879 100644
--- a/guix/inferior.scm
+++ b/guix/inferior.scm
@@ -709,20 +709,30 @@ prefix, resolve it; and if 'commit' is unset, fetch CHANNEL's branch tip."
           commit))))
 
 (define* (cached-channel-instance store
-                                  channels
+                                  channels-or-instances
                                   #:key
                                   (authenticate? #t)
                                   (cache-directory (%inferior-cache-directory))
                                   (ttl (* 3600 24 30)))
-  "Return a directory containing a guix filetree defined by CHANNELS, a list of channels.
-The directory is a subdirectory of CACHE-DIRECTORY, where entries can be reclaimed after TTL seconds.
-This procedure opens a new connection to the build daemon.  AUTHENTICATE?
-determines whether CHANNELS are authenticated."
+  "Return a directory containing a guix filetree defined by
+CHANNELS-OR-INSTANCES, a list of channels or channel instances.  The directory
+is a subdirectory of CACHE-DIRECTORY, where entries can be reclaimed after TTL
+seconds.  This procedure opens a new connection to the build daemon.
+AUTHENTICATE?  determines whether CHANNELS are authenticated."
+  ;; Determine if we are dealing with channels or channel instances.
+  (define channels?
+    (match (pk channels-or-instances)
+      (((? channel? c) rest ...)
+       #t)
+      (else #f)))
+
   (define commits
     ;; Since computing the instances of CHANNELS is I/O-intensive, use a
     ;; cheaper way to get the commit list of CHANNELS.  This limits overhead
     ;; to the minimum in case of a cache hit.
-    (map channel-full-commit channels))
+    (if channels?
+      (map channel-full-commit channels-or-instances)
+      (map channel-instance-commit channels-or-instances)))
 
   (define key
     (bytevector->base32-string
@@ -756,9 +766,12 @@ determines whether CHANNELS are authenticated."
       cached
       (run-with-store store
         (mlet* %store-monad ((instances
-                              -> (latest-channel-instances store channels
-                                                           #:authenticate?
-                                                           authenticate?))
+                              -> (if channels?
+                                     (latest-channel-instances
+                                      store channels-or-instances
+                                      #:authenticate?
+                                      authenticate?)
+                                     channels-or-instances))
                              (profile
                               (channel-instances->derivation instances)))
           (mbegin %store-monad
-- 
2.30.1