Don't use with-exception-handler with (backtrace)

With with-exception-handler being called with #:unwind? #f (implicitly). This
breaks Guile internals used by (backtrace) [1], meaning you get a different
exception/backtrace when Guile itself breaks.

This should avoid the "string->number: Wrong type argument in position
1 (expecting string): #f" exception I've been haunted by for the last year.

1: https://debbugs.gnu.org/cgi/bugreport.cgi?bug=46009

1 files changed, 7 insertions, 8 deletions

diff --git a/guix-build-coordinator/utils.scm b/guix-build-coordinator/utils.scm
index fdcefb6..4d98575 100644
--- a/guix-build-coordinator/utils.scm
+++ b/guix-build-coordinator/utils.scm
@@ -646,15 +646,14 @@ References: ~a~%"
                ;; Add the job back to the queue so that it's tried again
                (apply process-job job-args))
            (lambda ()
-             (with-exception-handler
-                 (lambda (exn)
-                   (simple-format (current-error-port)
-                                  "exception when handling job: ~A\n"
-                                  exn)
-                   (backtrace)
-                   (raise-exception exn))
+             (with-throw-handler #t
                (lambda ()
-                 (apply proc job-args))))
+                 (apply proc job-args))
+               (lambda (key . args)
+                 (simple-format (current-error-port)
+                                "exception when handling job: ~A ~A\n"
+                                key args)
+                 (backtrace))))
            #:unwind? #t)
          (with-mutex queue-mutex
            (hash-set! running-job-args