[bug#70169] [PATCH v2 06/12] maint: Generate 'doc/version-LANG.texi' reproducibly.

[Janneke Nieuwenhuizen <janneke@gnu.org>]

* doc/local.mk ($(srcdir)/doc/stamp-vti): Change rule into...
(version.texi-from-git): ...this new function.  Call it with vti,guix.texi,;
and for all MANUAL_LANGUAGES with $(i),po/doc/guix-manual.$(lang).po,
-$(lang.po).

Change-Id: Ia8df618178066cad320eecea0299337224e23a73
---
 doc/local.mk | 44 ++++++++++++++++++++++++++++++--------------
 1 file changed, 30 insertions(+), 14 deletions(-)

diff --git a/doc/local.mk b/doc/local.mk
index 017686137a..c355bec8d7 100644
--- a/doc/local.mk
+++ b/doc/local.mk
@@ -6,6 +6,7 @@
 # Copyright © 2016, 2018 Mathieu Lirzin <mthl@gnu.org>
 # Copyright © 2018, 2021 Julien Lepiller <julien@lepiller.eu>
 # Copyright © 2019 Timothy Sample <samplet@ngyro.com>
+# Copyright © 2024 Janneke Nieuwenhuizen <janneke@gnu.org>
 #
 # This file is part of GNU Guix.
 #
@@ -254,19 +255,34 @@ endif
 
 # Reproducible tarball
 
-# Generate 'version.texi' reproducibly using metadata from Git rather
-# than using metadata from the filesystem.
-$(srcdir)/doc/stamp-vti: $(srcdir)/doc/guix.texi $(top_srcdir)/configure
-	$(AM_V_GEN)set -e						\
+# Define a rule to build `version[LANG].texi' reproducibly using metadata from
+# Git rather than using metadata from the filesystem.
+define version.texi-from-git
+$(srcdir)/doc/stamp-$(1): $(srcdir)/$(2) $(top_srcdir)/configure
+	$$(AM_V_GEN)set -e						\
 	export LC_ALL=C;						\
 	export TZ=UTC0;							\
-	timestamp=$$(git log --pretty=format:%ct -n1 -- $< 2>/dev/null	\
-		|| echo $(SOURCE_DATE_EPOCH))				\
-	dmy=$$(date --date="@$$timestamp" "+%-d %B %Y");		\
-	my=$$(date --date="@$$timestamp" "+%B %Y");			\
-	{ echo "@set UPDATED $$dmy";					\
-	  echo "@set UPDATED-MONTH $$my";				\
-	  echo "@set EDITION $(VERSION)";				\
-	  echo "@set VERSION $(VERSION)"; } > $@-t;			\
-	mv $@-t $@
-	@cp $@ $(srcdir)/doc/version.texi
+	timestamp="$$$$(git log --pretty=format:%ct -n1 -- "$$<"	\
+		2>/dev/null						\
+		|| echo $$(SOURCE_DATE_EPOCH))"				\
+	dmy=$$$$(date --date="@$$$$timestamp" "+%-d %B %Y");		\
+	my=$$$$(date --date="@$$$$timestamp" "+%B %Y");			\
+	{ echo "@set UPDATED $$$$dmy";					\
+	  echo "@set UPDATED-MONTH $$$$my";				\
+	  echo "@set EDITION $$$(VERSION)";				\
+	  echo "@set VERSION $$$(VERSION)"; } > "$$@-t";
+	mv "$$@-t" "$$@"
+	cp -p "$$@" "$$(srcdir)/doc/version$(3).texi"
+endef
+
+# Generate rules for stamp-vti and stamp-N that create version.texi and
+# version-LANG.texi to override the Autotools versions that use timestamps
+# embedded in the file-system.  These are expected to generate warnings:
+#
+#   Makefile:7376: warning: overriding recipe for target 'doc/stamp-vti'
+#   Makefile:5098: warning: ignoring old recipe for target 'doc/stamp-vti'
+i:=0
+$(eval $(call version.texi-from-git,vti,doc/guix.texi,))
+$(foreach lang, $(MANUAL_LANGUAGES),							\
+  $(eval i=$(shell echo $$(($(i)+1))))							\
+  $(eval $(call version.texi-from-git,$(i),po/doc/guix-manual.$(lang).po,-$(lang))))
-- 
2.41.0