Make ERC's format catalogs more extensible

* lisp/erc/erc-common.el (erc--define-catalog): Accept a `:parent'
keyword to allow for extending an existing catalog by overriding some
subset of defined entries.
(erc-define-message-format-catalog): Add edebug spec.
* lisp/erc/erc.el (erc-retrieve-catalog-entry): Check parent for
definition before looking to `default-toplevel-value'.
* test/lisp/erc/erc-tests.el (erc-retrieve-catalog-entry): Add test
case for inheritance.
* test/lisp/erc/resources/erc-tests-common.el
(erc-tests-common-pp-propertized-parts): Fix bug in convenience
command.  (Bug#67677)

2 files changed, 16 insertions, 2 deletions

diff --git a/test/lisp/erc/erc-tests.el b/test/lisp/erc/erc-tests.el
index a9aa255718d..a71cc806f6a 100644
--- a/test/lisp/erc/erc-tests.el
+++ b/test/lisp/erc/erc-tests.el
@@ -3533,6 +3533,20 @@ connection."
   (should (equal (erc-retrieve-catalog-entry 's221) "test-top 221 val"))
 
   (makunbound (intern "erc-message-test-top-s221"))
-  (unintern "erc-message-test-top-s221" obarray))
+  (unintern "erc-message-test-top-s221" obarray)
+
+  ;; Inheritance.
+  (let ((obarray (obarray-make)))
+    (set (intern "erc-message-test1-abc") "val test1 abc")
+    (set (intern "erc-message-test2-abc") "val test2 abc")
+    (set (intern "erc-message-test2-def") "val test2 def")
+    (put (intern "test0") 'erc--base-format-catalog (intern "test1"))
+    (put (intern "test1") 'erc--base-format-catalog (intern "test2"))
+    (should (equal (erc-retrieve-catalog-entry 'abc (intern "test0"))
+                   "val test1 abc"))
+    (should (equal (erc-retrieve-catalog-entry 'def (intern "test0"))
+                   "val test2 def"))
+    ;; Terminates.
+    (should-not (erc-retrieve-catalog-entry 'ghi (intern "test0")))))
 
 ;;; erc-tests.el ends here
diff --git a/test/lisp/erc/resources/erc-tests-common.el b/test/lisp/erc/resources/erc-tests-common.el
index fc5649798b5..906aa891352 100644
--- a/test/lisp/erc/resources/erc-tests-common.el
+++ b/test/lisp/erc/resources/erc-tests-common.el
@@ -150,7 +150,7 @@ between literal strings."
 For simplicity, assume string evaluates to itself."
   (interactive "P")
   (let ((sexp (erc-tests-common-string-to-propertized-parts (pp-last-sexp))))
-    (if arg (insert (pp-to-string sexp)) (pp-eval-expression sexp))))
+    (if arg (insert (pp-to-string sexp)) (pp-macroexpand-expression sexp))))
 
 ;; The following utilities are meant to help prepare tests for
 ;; `erc--get-inserted-msg-bounds' and friends.