[1.50][PATCH 5/5] build: Catch and error upon circular task references

["Anuj Mittal" <anuj.mittal@intel.com>]

From: Richard Purdie <richard.purdie@linuxfoundation.org>

If there are circular task references, error on them rather than show
a recursion error. A simple reproducer is:

"""
do_packageswu () {
       :
}

addtask do_packageswu after do_image_complete before do_image_qa
"""

into image_types.bbclass. There is code in runqueue to detect these but
we never get that far with the current codebase.

[YOCTO #13140]

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit 339d4d6be515a71311b81fb9e99742af0d8a5130)
Signed-off-by: Anuj Mittal <anuj.mittal@intel.com>
---
 lib/bb/build.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/lib/bb/build.py b/lib/bb/build.py
index b2715fc53..24ce327c5 100644
--- a/lib/bb/build.py
+++ b/lib/bb/build.py
@@ -1025,6 +1025,8 @@ def tasksbetween(task_start, task_end, d):
     def follow_chain(task, endtask, chain=None):
         if not chain:
             chain = []
+        if task in chain:
+            bb.fatal("Circular task dependencies as %s depends on itself via the chain %s" % (task, " -> ".join(chain)))
         chain.append(task)
         for othertask in tasks:
             if othertask == task:
-- 
2.31.1