Subject: Re: [bug#36841] [PATCH] build/cargo-build-system: Patch cargo checksums.

From: Efraim Flashner <[email-masked]>
Date: Tue, 30 Jul 2019 11:17:57 +0300

On Mon, Jul 29, 2019 at 06:44:31PM -0700, Ivan Petkov wrote:
> Hi Efraim,
> 
> > On Jul 29, 2019, at 12:04 PM, Efraim Flashner <[email-masked]> wrote:
> > 
> > +;; After patching the 'patch-generated-file-shebangs phase any vendored crates
> > +;; will have a mismatch on their checksum.
> > +(define* (patch-cargo-checksums #:key
> > +                                (vendor-dir "guix-vendor")
> > +                                #:allow-other-keys)
> 
> [snip]
> 
> > +    (replace 'install install)
> > +    (add-after 'patch-generated-file-shebangs 'patch-cargo-checksums patch-cargo-checksums)))
> 
> I can’t quite remember the order the phases run in off the top of my head. Would it be possible to
> make the configure/checksum generation phase run after shebang-patching (or ensure the patching
> happens first)? It would avoid having to checksum all the files twice that way…

The 'configure phase could be renamed the plop-vendored-crates-into-place
phase. It actually can't come after the 'patch-generated-file-shebangs
phase since then there won't be any vendored crates to patch.

If we remove the generate-checksums call from 'configure then there
won't be a .cargo-checksum.json to remove and regenerate during the
'patch-cargo-checksums phase, so I've changed that to search for
"Cargo.toml$" and not delete it. Not as robust as "for each top-level
directory in the 'vendor-dir'", but should be good enough.

-- 
Efraim Flashner   <[email-masked]>   אפרים פלשנר
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From abf262fbe7ed8d9a532a3ce63cb7453c1666d914 Mon Sep 17 00:00:00 2001
From: Efraim Flashner <[email-masked]>
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 <[email-masked]>
 ;;; Copyright © 2017 Mathieu Othacehe <[email-masked]>
 ;;; Copyright © 2019 Ivan Petkov <[email-masked]>
+;;; Copyright © 2019 Efraim Flashner <[email-masked]>
 ;;;
 ;;; 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