From abf262fbe7ed8d9a532a3ce63cb7453c1666d914 Mon Sep 17 00:00:00 2001
From: Efraim Flashner <address@hidden>
Date: Mon, 29 Jul 2019 22:01:05 +0300
Subject: [PATCH] build/cargo-build-system: Patch cargo checksums.

* guix/build/cargo-build-system.scm (update-cargo-lock,
patch-cargo-checksums): New phases.
(%standard-phases): Add 'update=cargo-lock after 'configure and
'patch-cargo-checksums after 'patch-generated-file-shebangs.
---
 guix/build/cargo-build-system.scm | 37 ++++++++++++++++++++++++++++---
 1 file changed, 34 insertions(+), 3 deletions(-)

diff --git a/guix/build/cargo-build-system.scm b/guix/build/cargo-build-system.scm
index f38de16cf7..dfc7923c8d 100644
--- a/guix/build/cargo-build-system.scm
+++ b/guix/build/cargo-build-system.scm
@@ -2,6 +2,7 @@
 ;;; Copyright © 2016 David Craven <address@hidden>
 ;;; Copyright © 2017 Mathieu Othacehe <address@hidden>
 ;;; Copyright © 2019 Ivan Petkov <address@hidden>
+;;; Copyright © 2019 Efraim Flashner <address@hidden>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -94,8 +95,7 @@ Cargo.toml file present at its root."
               ;; so that we can generate any cargo checksums.
               ;; The --strip-components argument is needed to prevent creating
               ;; an extra directory within `crate-dir`.
-              (invoke "tar" "xvf" path "-C" crate-dir "--strip-components" "1")
-              (generate-checksums crate-dir)))))
+              (invoke "tar" "xvf" path "-C" crate-dir "--strip-components" "1")))))
     inputs)
 
   ;; Configure cargo to actually use this new directory.
@@ -121,6 +121,35 @@ directory = '" port)
   (setenv "CC" (string-append (assoc-ref inputs "gcc") "/bin/gcc"))
   #t)
 
+;; The Cargo.lock file tells the build system which crates are required for
+;; building and hardcodes their version and checksum.  In order to build with
+;; the inputs we provide, we need to recreate the file with our inputs.
+(define* (update-cargo-lock #:key
+                            (vendor-dir "guix-vendor")
+                            #:allow-other-keys)
+  "Regenerate the Cargo.lock file with the current build inputs."
+  (when (file-exists? "Cargo.lock")
+    (begin
+      (delete-file "Cargo.lock")
+      (invoke "cargo" "generate-lockfile")))
+  #t)
+
+;; After the 'patch-generated-file-shebangs phase any vendored crates who have
+;; their shebangs patched will have a mismatch on their checksum.
+(define* (patch-cargo-checksums #:key
+                                (vendor-dir "guix-vendor")
+                                #:allow-other-keys)
+  "Patch the checksums of the vendored crates after patching their shebangs."
+  (for-each
+    (lambda (filename)
+      (let* ((dir (dirname filename)))
+        (display (string-append
+                   "patch-cargo-checksums: generate-checksums for "
+                   dir "\n"))
+        (generate-checksums dir)))
+    (find-files "guix-vendor" "Cargo.toml$"))
+  #t)
+
 (define* (build #:key
                 skip-build?
                 (cargo-build-flags '("--release"))
@@ -162,7 +191,9 @@ directory = '" port)
     (replace 'configure configure)
     (replace 'build build)
     (replace 'check check)
-    (replace 'install install)))
+    (replace 'install install)
+    (add-after 'configure 'update-cargo-lock update-cargo-lock)
+    (add-after 'patch-generated-file-shebangs 'patch-cargo-checksums patch-cargo-checksums)))
 
 (define* (cargo-build #:key inputs (phases %standard-phases)
                       #:allow-other-keys #:rest args)
-- 
2.22.0