[nongnu] elpa/sly 8074da031e: Fix #492: Rework handling of SBCL's package variance warning

[ELPA Syncer]

branch: elpa/sly
commit 8074da031ed9d677abc77fb3dab4bb42c6be76c3
Author: daewok <daewok@users.noreply.github.com>
Commit: GitHub <noreply@github.com>

    Fix #492: Rework handling of SBCL's package variance warning
    
    Recompiling slynk-backend.lisp and slynk.lisp causes SBCL to emit
    package variance warnings. Currently, these are handled by wrapping
    `(asdf:load-system "slynk")`. Unfortunately, this does not cover use
    cases where slynk is loaded as a dependency of another library.
    
    At least [40ants-doc][1] has added Slynk as a dependency, making it
    much more likely that Slynk will be recompiled outside of a call to
    load Slynk directly.
    
    We can handle this by moving the logic to handle the package variance
    warning to the :AROUND-COMPILE ASDF hook of the slynk-backend.lisp and
    slynk.lisp files.
    
    :AROUND-COMPILE with a LAMBDA was introduced in [ASDF 2.019][2].
    
    If the minimum required ASDF version is bumped to something closer to
    ASDF 3, more (better) options become available to handle this, as
    noted in the comments.
    
    The only observable change should be that prior to this commit,
    `(asdf:load-system "slynk")` would signal a
    UIOP::COMPILE-WARNED-WARNING condition, but after this commit no
    warning at all is signaled and nothing is printed that indicates there
    was a warning. This is a bit unfortunate, as there could be other, non
    package-variance, warnings that would be silently missed. But it's the
    best I could come up with without requiring ASDF 3 or using a symbol
    from SB-INT.
    
    [1]: https://github.com/40ants/doc
    [2]: 
https://gitlab.common-lisp.net/asdf/asdf/-/blob/9dc59bb27c5251e954d6847cc1b507c5f399da7b/doc/Changelog#L984
---
 slynk/slynk.asd | 21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/slynk/slynk.asd b/slynk/slynk.asd
index 2043c8c9c8..97e7a2f0de 100644
--- a/slynk/slynk.asd
+++ b/slynk/slynk.asd
@@ -20,7 +20,16 @@
 (defsystem :slynk
   :serial t
   :components
-  ((:file "slynk-backend")
+  ((:file "slynk-backend"
+    ;; If/when we require ASDF3, we can use UIOP:DEFINE-PACKAGE instead or use
+    ;; UIOP:MATCH-CONDITION-P to muffle only the package variance
+    ;; warning. Alternatively, SBCL could export the package variance warning
+    ;; from SB-EXT and we can muffle it directly.
+    #+sbcl :around-compile
+    #+sbcl #1=(lambda (thunk)
+                (handler-bind (((and warning (not style-warning)) 
#'muffle-warning))
+                  (let ((sb-ext:*on-package-variance* '(:warn t)))
+                    (funcall thunk)))))
    ;; If/when we require ASDF3, we shall use :if-feature instead
    #+(or cmu sbcl scl)
    (:file "slynk-source-path-parser")
@@ -60,7 +69,9 @@
    (:file "slynk-gray")
    (:file "slynk-match")
    (:file "slynk-rpc")
-   (:file "slynk")
+   (:file "slynk"
+    #+sbcl :around-compile
+    #+sbcl #1#)
    (:file "slynk-completion")
    (:file "slynk-apropos")))
 
@@ -68,12 +79,6 @@
   (format *debug-io* "~&SLYNK's ASDF loader finished.")
   (funcall (read-from-string "slynk::init")))
 
-#+sbcl
-(defmethod operate :around ((o load-op) (c (eql (find-system :slynk))) &key 
&allow-other-keys)
-  (let ((asdf:*compile-file-failure-behaviour* :warn)
-        (sb-ext:*on-package-variance* '(:warn t)))
-    (call-next-method)))
-
 
 ;;; Contrib systems (should probably go into their own file one day)
 ;;;