From b43c292077a5f8266e19da99edf936624645d037 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kasper=20Ga=C5=82kowski?= <galkowskikasper@gmail.com>
Date: Sat, 7 Dec 2024 02:46:47 +0100
Subject: [PATCH] lisp-modules: detect circular dependencies during quicklisp
 import

Quicklisp's October 2024 release had such a problem between the new packages qvm
and cl-quil. It caused an issue with the "nixpkgs-review" tool because the Nix
interpreter was stopping with an error due to too much recursion.
---
 .../import/repository/quicklisp.lisp          | 38 ++++++++++++++-----
 1 file changed, 28 insertions(+), 10 deletions(-)

diff --git a/pkgs/development/lisp-modules/import/repository/quicklisp.lisp b/pkgs/development/lisp-modules/import/repository/quicklisp.lisp
index 9666fc9fba2a..634795ab17a4 100644
--- a/pkgs/development/lisp-modules/import/repository/quicklisp.lisp
+++ b/pkgs/development/lisp-modules/import/repository/quicklisp.lisp
@@ -120,16 +120,34 @@
                                                                asds
                                                                'vector))))))
 
-      ;; Skip known broken systems and their dependents
-      (dolist (system *broken-systems*)
-        (sql-query
-         "with recursive broken(name) as (
-            select ?
-            union
-            select s.name from quicklisp_system s, broken b
-            where b.name in (select value from json_each(deps))
-          ) delete from quicklisp_system where name in (select name from broken)"
-          system))
+      ;; Weed out circular dependencies from the package graph.
+      (sqlite:with-transaction db
+        (sql-query "create temp table will_delete (root,name)")
+        (loop for (system) in (sql-query "select name from quicklisp_system") do
+          (when (sql-query
+                  "with recursive dep(root, name) as (
+                    select s.name, d.value
+                    from quicklisp_system s
+                    cross join json_each(s.deps) d
+                    where s.name = ?
+                    union
+                    select dep.root, d.value
+                    from quicklisp_system s, dep
+                    cross join json_each(s.deps) d
+                    where s.name = dep.name
+                  ) select 1 from dep where name = root"
+                 system)
+            (sql-query
+             "with recursive broken(name) as (
+                select ?
+                union
+                select s.name from quicklisp_system s, broken b
+                where b.name in (select value from json_each(s.deps))
+              ) insert into will_delete select ?, name from broken"
+             system system)))
+        (loop for (root name) in (sql-query "select root, name from will_delete") do
+          (warn "Circular dependency in '~a': Omitting '~a'" root name)
+          (sql-query "delete from quicklisp_system where name = ?" name)))
 
       (sqlite:with-transaction db
         ;; Should these be temp tables, that then get queried by