From a255def01960a72d2c62be51251c1923a27da18d Mon Sep 17 00:00:00 2001
From: Matthew Flatt <mflatt@racket-lang.org>
Date: Sat, 17 Nov 2018 16:30:56 -0700
Subject: [PATCH] cs: fix state of module instance interrupted by error

Closes #2380
---
 pkgs/racket-test-core/tests/racket/module.rktl | 15 +++++++++++++++
 racket/src/schemify/schemify.rkt               | 17 ++++++++++++-----
 2 files changed, 27 insertions(+), 5 deletions(-)

diff --git a/pkgs/racket-test-core/tests/racket/module.rktl b/pkgs/racket-test-core/tests/racket/module.rktl
index ae5df56829..af438f2d76 100644
--- a/pkgs/racket-test-core/tests/racket/module.rktl
+++ b/pkgs/racket-test-core/tests/racket/module.rktl
@@ -2786,6 +2786,21 @@ case of module-leve bindings; it doesn't cover local bindings.
                   'module-begin
                   (list #'module* #'stop))))
 
+;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; Check state of a module-instance namespace when initialization
+;; is interrupted by an error
+
+(module fails-after-f-and-before-g racket/base
+  (provide f g)
+  (define (f x) (error "boom"))
+  (f 42)
+  (define g (if (zero? (random 1)) 'ok 'oops)))
+
+(err/rt-test (dynamic-require ''fails-after-f-and-before-g #f)
+             (lambda (x) (and (exn:fail? x)
+                              (regexp-match? #rx"boom" (exn-message x)))))
+(test #t procedure? (eval 'f (module->namespace ''fails-after-f-and-before-g)))
+
 ;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
 (report-errs)
diff --git a/racket/src/schemify/schemify.rkt b/racket/src/schemify/schemify.rkt
index 38d9c5dbfe..b62caf4bfb 100644
--- a/racket/src/schemify/schemify.rkt
+++ b/racket/src/schemify/schemify.rkt
@@ -188,12 +188,13 @@
   (define schemified
     (let loop ([l l] [in-mut-l l] [accum-exprs null] [accum-ids null])
       (define mut-l (update-mutated-state! l in-mut-l mutated))
+      (define (make-set-variables)
+        (for/list ([id (in-list accum-ids)]
+                   #:when (hash-ref exports id #f))
+          (make-set-variable id exports knowns mutated)))
       (cond
        [(null? l)
-        (define set-vars
-          (for/list ([id (in-list accum-ids)]
-                     #:when (hash-ref exports id #f))
-            (make-set-variable id exports knowns mutated)))
+        (define set-vars (make-set-variables))
         (cond
          [(null? set-vars)
           (cond
@@ -234,7 +235,13 @@
                 [else
                  (id-loop (wrap-cdr ids) accum-exprs (cons (unwrap (wrap-car ids)) accum-ids))]))))]
           [`,_
-           (loop (wrap-cdr l) mut-l (cons schemified accum-exprs) accum-ids)])])))
+           ;; In case `schemified` triggers an error, sync exported variables
+           (define set-vars (make-set-variables))
+           (cond
+             [(null? set-vars)
+              (loop (wrap-cdr l) mut-l (cons schemified accum-exprs) null)]
+             [else
+              (loop (wrap-cdr l) mut-l (cons schemified (append (reverse set-vars) accum-exprs)) null)])])])))
   ;; Return both schemified and known-binding information, where
   ;; the later is used for cross-linklet optimization
   (values schemified knowns mutated))