[bug#71580] [PATCH] doc: Add message for common error about make check-system

[Richard Sent <richard@freakingpenguin.com>]

* doc/contributing.texi (Running the Test Suite): Mention that make clean-go
may need to be run before running make check-system when previous builds were
run with different work trees. See https://issues.guix.gnu.org/47573.

Change-Id: I4b68d3a05f1425505816db969284487d725840d6
---
Sending a followup rebased on current master.

 doc/contributing.texi | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/doc/contributing.texi b/doc/contributing.texi
index 938c8bfdb1..c9591dc9bf 100644
--- a/doc/contributing.texi
+++ b/doc/contributing.texi
@@ -411,6 +411,20 @@ Running the Test Suite
 substitutes are available for their dependencies (@pxref{Substitutes}).
 Some of them require a lot of storage space to hold VM images.
 
+If you encounter an error like:
+
+@example
+Compiling Scheme modules...
+ice-9/eval.scm:142:16: In procedure compile-top-call:
+error: all-system-tests: unbound variable
+hint: Did you forget `(use-modules (gnu tests))'?
+@end example
+
+@noindent
+there may be inconsistency in the work tree from previous builds.  To
+resolve this, try running @command{make clean-go} followed by
+@command{make}.
+
 Again in case of test failures, please send @email{bug-guix@@gnu.org}
 all the details.
 

base-commit: 612e4dd98f7d1d015e405af9d029bede3fe3c280
-- 
2.45.1