diff options
| -rw-r--r-- | guix/gexp.scm | 15 | ||||
| -rw-r--r-- | guix/monads.scm | 15 |
2 files changed, 26 insertions, 4 deletions
diff --git a/guix/gexp.scm b/guix/gexp.scm index f7c064297b..5b5b064b59 100644 --- a/guix/gexp.scm +++ b/guix/gexp.scm @@ -920,7 +920,18 @@ and in the current monad setting (system type, etc.)" (simple-format #f "~a:~a" line column))) "<unknown location>"))) -(define-syntax-parameter current-imported-modules +(define-syntax-rule (define-syntax-parameter-once name proc) + ;; Like 'define-syntax-parameter' but ensure the top-level binding for NAME + ;; does not get redefined. This works around a race condition in a + ;; multi-threaded context with Guile <= 2.2.4: <https://bugs.gnu.org/27476>. + (eval-when (load eval expand compile) + (define name + (if (module-locally-bound? (current-module) 'name) + (module-ref (current-module) 'name) + (make-syntax-transformer 'name 'syntax-parameter + (list proc)))))) + +(define-syntax-parameter-once current-imported-modules ;; Current list of imported modules. (identifier-syntax '())) @@ -931,7 +942,7 @@ environment." (identifier-syntax modules))) body ...)) -(define-syntax-parameter current-imported-extensions +(define-syntax-parameter-once current-imported-extensions ;; Current list of extensions. (identifier-syntax '())) diff --git a/guix/monads.scm b/guix/monads.scm index 6ae616aca9..6924471345 100644 --- a/guix/monads.scm +++ b/guix/monads.scm @@ -274,12 +274,23 @@ more optimizations." (_ #'generic-name)))))))))) -(define-syntax-parameter >>= +(define-syntax-rule (define-syntax-parameter-once name proc) + ;; Like 'define-syntax-parameter' but ensure the top-level binding for NAME + ;; does not get redefined. This works around a race condition in a + ;; multi-threaded context with Guile <= 2.2.4: <https://bugs.gnu.org/27476>. + (eval-when (load eval expand compile) + (define name + (if (module-locally-bound? (current-module) 'name) + (module-ref (current-module) 'name) + (make-syntax-transformer 'name 'syntax-parameter + (list proc)))))) + +(define-syntax-parameter-once >>= ;; The name 'bind' is already taken, so we choose this (obscure) symbol. (lambda (s) (syntax-violation '>>= ">>= (bind) used outside of 'with-monad'" s))) -(define-syntax-parameter return +(define-syntax-parameter-once return (lambda (s) (syntax-violation 'return "return used outside of 'with-monad'" s))) |