diff --git a/core/src/nix/drv.sld b/core/src/nix/drv.sld
index 20c54cc..8ca9666 100644
--- a/core/src/nix/drv.sld
+++ b/core/src/nix/drv.sld
@@ -230,7 +230,8 @@
                     ("builder" . ,(car builder))
                     ("system" . ,platform)
                     . ,new-items)))
-      (make-derivation name (list (cons "out" output)) input-drvs input-srcs platform (car builder) (cdr builder) (list-sort env-pair< (append new-items env)) (make-derivation-metadata #f #f #f #f #f)))
+      (define environment (list-sort env-pair< (filter-environment env new-items)))
+      (make-derivation name (list (cons "out" output)) input-drvs (list-sort string<? (filter-sources input-srcs)) platform (car builder) (cdr builder) environment (make-derivation-metadata #f #f #f #f #f)))
 
     (define (sanity-check-drv orig-drv)
       (define tmp-drv (mask-derivation orig-drv))
@@ -247,9 +248,15 @@
       (for-each (lambda (kv) (unless (assoc (car kv) output string=?) (set! output (cons kv output)))) env-list)
       output)
 
+    (define (filter-sources inputs)
+      (define output '())
+      (for-each (lambda (out) (unless (member out output string=?) (set! output (cons out output)))) inputs)
+      output)
+
     ;; Creates an input-addressed derivation with specified parameters.
     (define (make-input-addressed-derivation name platform input-drvs input-srcs builder env outputs)
       (define compat-env (if (%derivation-compatible) `(("name" . ,name) ("builder" . ,(car builder)) ("system" . ,platform)) '()))
+      (set! input-srcs (list-sort string<? (filter-sources input-srcs)))
 
       (define tmp-outputs (list-sort env-pair< (map (lambda (l) (cons l (make-derivation-output #f #f #f #f))) outputs)))
       (define tmp-env (list-sort env-pair< (filter-environment env (append compat-env (map (lambda (l) (cons l "")) outputs)))))
@@ -287,7 +294,7 @@
                                                                      #f 'floating "sha256" #t))) noutputs)))
       (define env (list-sort env-pair< (filter-environment nenv (append compat-env (map (lambda (l) (cons (car l) (make-placeholder (car l)))) outputs)))))
 
-      (define drv (make-derivation name outputs input-drvs input-srcs platform (car builder) (cdr builder) env (make-derivation-metadata #f #f #t #f #f)))
+      (define drv (make-derivation name outputs input-drvs (list-sort string<? (filter-sources input-srcs)) platform (car builder) (cdr builder) env (make-derivation-metadata #f #f #t #f #f)))
       (define pathhash (string-copy (derivation-path drv) (+ 1 (string-length (%store-dir))) (+ 33 (string-length (%store-dir)))))
       (for-each (lambda (pair) (set-derivation-output-path! (cdr pair) (make-upstream-output-placeholder pathhash name (car pair)))) (derivation-outputs drv))
       drv)