[bug#45601] [PATCH 6/6] gnu: vlang: Fix v tools.

[Ryan Prior via Guix-patches via <guix-patches@gnu.org>]

---
 gnu/local.mk                                  |  1 +
 .../vlang-accommodate-timestamps.patch        | 50 +++++++++++++++++++
 gnu/packages/vlang.scm                        |  7 +++
 3 files changed, 58 insertions(+)
 create mode 100644 gnu/packages/patches/vlang-accommodate-timestamps.patch

diff --git a/gnu/local.mk b/gnu/local.mk
index 2402b1e349..168c499976 100644
--- a/gnu/local.mk
+++ b/gnu/local.mk
@@ -1702,6 +1702,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/vinagre-newer-freerdp.patch             \
   %D%/packages/patches/vinagre-newer-rdp-parameters.patch      \
   %D%/packages/patches/virglrenderer-CVE-2017-6386.patch 	\
+  %D%/packages/patches/vlang-accommodate-timestamps.patch 	\
   %D%/packages/patches/vorbis-tools-CVE-2014-9638+CVE-2014-9639.patch		\
   %D%/packages/patches/vorbis-tools-CVE-2014-9640.patch		\
   %D%/packages/patches/vorbis-tools-CVE-2015-6749.patch		\
diff --git a/gnu/packages/patches/vlang-accommodate-timestamps.patch b/gnu/packages/patches/vlang-accommodate-timestamps.patch
new file mode 100644
index 0000000000..02171ac6cf
--- /dev/null
+++ b/gnu/packages/patches/vlang-accommodate-timestamps.patch
@@ -0,0 +1,50 @@
+From 64e7c548843c7938fcfa6b697108d28aa26f4d69 Mon Sep 17 00:00:00 2001
+From: Ryan Prior <rprior@protonmail.com>
+Date: Thu, 31 Dec 2020 02:31:38 -0600
+Subject: [PATCH] v.util: accomodate reproducible build environments like guix,
+ by not recompiling cmd/tools when mtime < 1024 (#7702)
+
+---
+ vlib/v/util/util.v | 16 ++++++++++++++--
+ 1 file changed, 14 insertions(+), 2 deletions(-)
+
+diff --git a/vlib/v/util/util.v b/vlib/v/util/util.v
+index 811b71585..1ed32bacf 100644
+--- a/vlib/v/util/util.v
++++ b/vlib/v/util/util.v
+@@ -179,7 +179,10 @@ pub fn should_recompile_tool(vexe string, tool_source string) bool {
+ 	if !os.exists(tool_exe) {
+ 		should_compile = true
+ 	} else {
+-		if os.file_last_mod_unix(tool_exe) <= os.file_last_mod_unix(vexe) {
++		mtime_vexe := os.file_last_mod_unix(vexe)
++		mtime_tool_exe := os.file_last_mod_unix(tool_exe)
++		mtime_tool_source := os.file_last_mod_unix(tool_source)
++		if mtime_tool_exe <= mtime_vexe {
+ 			// v was recompiled, maybe after v up ...
+ 			// rebuild the tool too just in case
+ 			should_compile = true
+@@ -192,10 +195,19 @@ pub fn should_recompile_tool(vexe string, tool_source string) bool {
+ 				should_compile = false
+ 			}
+ 		}
+-		if os.file_last_mod_unix(tool_exe) <= os.file_last_mod_unix(tool_source) {
++		if mtime_tool_exe <= mtime_tool_source {
+ 			// the user changed the source code of the tool, or git updated it:
+ 			should_compile = true
+ 		}
++		// GNU Guix and possibly other environments, have bit for bit reproducibility in mind,
++		// including filesystem attributes like modification times, so they set the modification
++		// times of executables to a small number like 0, 1 etc. In this case, we should not
++		// recompile even if other heuristics say that we should. Users in such environments,
++		// have to explicitly do: `v cmd/tools/vfmt.v`, and/or install v from source, and not
++		// use the system packaged one, if they desire to develop v itself.
++		if mtime_vexe < 1024 && mtime_tool_exe < 1024 {
++			should_compile = false
++		}
+ 	}
+ 	return should_compile
+ }
+-- 
+2.29.2
+
diff --git a/gnu/packages/vlang.scm b/gnu/packages/vlang.scm
index 92d178a3e1..3bdbf36f9d 100644
--- a/gnu/packages/vlang.scm
+++ b/gnu/packages/vlang.scm
@@ -30,6 +30,7 @@
   #:use-module (gnu packages version-control)
   #:use-module (gnu packages javascript)
   #:use-module (gnu packages xorg)
+  #:use-module (gnu packages)
   #:use-module (guix build-system gnu)
   #:use-module (guix git-download)
   #:use-module ((guix licenses) #:prefix license:)
@@ -61,6 +62,12 @@
      (sha256
       (base32 "1x2sf2j6xl11kjvv0i0anjqwsfb1la11xr7yhdnbix9808442wm2"))
      (modules '((guix build utils)))
+     ;; This patch is already accepted upstream but is required for version
+     ;; 0.2. The package will build without it, but it will fail to run any v
+     ;; tools afterwards because of how Guix changes modified timestamps in
+     ;; the package files.
+     (patches (search-patches
+               "vlang-accommodate-timestamps.patch"))
      (snippet
       '(begin
          ;; Eventually remove the whole thirdparty directory.
-- 
2.29.2