From 9ddb5043e3c9963113bd16384225ef1b57dd6ac0 Mon Sep 17 00:00:00 2001
From: Steve Vinoski <vinoski@ieee.org>
Date: Sun, 30 Jan 2022 22:23:53 -0500
Subject: [PATCH] Fix handling of SOURCE_DATE_EPOCH

If no SOURCE_DATE_EPOCH is specified via configure, then it can't be
set as an environment variable in doc/Makefile.am build rules. Change
the build rules to check if SOURCE_DATE_EPOCH is non-empty and use it
if so, otherwise leave it out of the commands.

Also fix verbosity for make in doc/Makefile.am. If V=1 is passed on
the make command line, echo the build commands, otherwise echo
abbreviated commands. Special handling is needed because of the "if"
commands in the build rules have echo unconditionally disabled via @.
---
 README.md       |  5 ++-
 doc/Makefile.am | 93 ++++++++++++++++++++++++++++++++++++++++++-------
 2 files changed, 84 insertions(+), 14 deletions(-)

diff --git a/README.md b/README.md
index ad66f220..c0fe75d7 100644
--- a/README.md
+++ b/README.md
@@ -140,7 +140,10 @@ The above configurations for enabling deterministic builds add the erlc flag
 `yaws_generated.beam`, and set e.g. creation date in `yaws.ps` and `yaws.pdf`
 from the value of `SOURCE_DATE_EPOCH`, which is expected to be an integer
 reflecting a number of seconds since the Unix epoch. (One way to get an epoch
-integer value is via the command `date '+%s'` on Linux or macOS, for example.)
+integer value is via the command `date '+%s'` on Linux or macOS, for example.
+If you're using the bash shell version 4.2 or newer, `printf '%(%s)T\n' -1`
+gives an epoch integer value, and starting at version 5, the bash shell
+provides the `$EPOCHSECONDS` variable.)
 
 Note that various paths in configuration files, templates, examples etc. are
 generated from the configured installation prefix config files; thus they
diff --git a/doc/Makefile.am b/doc/Makefile.am
index 85de6afd..4b74a1fd 100644
--- a/doc/Makefile.am
+++ b/doc/Makefile.am
@@ -47,10 +47,26 @@ endif
 
 # For reproducible builds, SOURCE_DATE_EPOCH replaces DVIPSSource date if set
 yaws.ps: yaws.dvi
-	$(AM_V_GEN)TEXINPUTS="$${TEXTINPUTS}:@srcdir@" \
+	@if [ x"$(SOURCE_DATE_EPOCH)" == x ]; then \
+	  if [ x'$(AM_V_GEN)' != x ]; then \
+	    echo '  $(DVIPS)     $<' ; \
+	  else \
+	    echo TEXINPUTS="$${TEXTINPUTS}:@srcdir@" \
+		$(DVIPS) -q -o $@ $< ; \
+	  fi; \
+	  TEXINPUTS="$${TEXTINPUTS}:@srcdir@" \
+		$(DVIPS) -q -o $@ $< ; \
+	else \
+	  if [ x'$(AM_V_GEN)' != x ]; then \
+	    echo '  $(DVIPS)     $<' ; \
+	  else \
+	    echo TEXINPUTS="$${TEXTINPUTS}:@srcdir@" \
 		SOURCE_DATE_EPOCH=$(SOURCE_DATE_EPOCH) \
-		$(DVIPS) -q -o $@ $<
-	$(AM_V_at)if [ x"$(SOURCE_DATE_EPOCH)" != "x" ]; then \
+		$(DVIPS) -q -o $@ $< ; \
+	  fi; \
+	  TEXINPUTS="$${TEXTINPUTS}:@srcdir@" \
+		SOURCE_DATE_EPOCH=$(SOURCE_DATE_EPOCH) \
+		$(DVIPS) -q -o $@ $< ; \
 	  code='{{Y,Mo,D},{H,Mi,S}} = calendar:system_time_to_local_time('$(SOURCE_DATE_EPOCH)', 1),' ; \
 	  code="$$code "'io:format("~4.4w~2.2.0w~2.2.0w:~2.2.0w~2.2.0w~2.2.0w\n", [Y,Mo,D,H,Mi,S]).' ; \
 	  newdate=`$(ERL) -noshell -noinput -eval "$$code" -s init stop` || exit 1; \
@@ -62,24 +78,75 @@ yaws.ps: yaws.dvi
 	fi
 
 yaws.pdf: yaws.tex $(IMG_PDF)
-	$(AM_V_GEN)TEXINPUTS="$${TEXTINPUTS}:@srcdir@" \
+	@if [ x"$(SOURCE_DATE_EPOCH)" != x ]; then \
+	  if [ x'$(AM_V_GEN)' != x ]; then \
+	    echo '  $(PDFLATEX)  $<' ; \
+	  else \
+	    echo TEXINPUTS="$${TEXTINPUTS}:@srcdir@" \
+		SOURCE_DATE_EPOCH=$(SOURCE_DATE_EPOCH) \
+		$(PDFLATEX) $< ; \
+	  fi ; \
+	  TEXINPUTS="$${TEXTINPUTS}:@srcdir@" \
 		SOURCE_DATE_EPOCH=$(SOURCE_DATE_EPOCH) \
-		$(PDFLATEX) yaws.tex > /dev/null
-	$(AM_V_at)TEXINPUTS="$${TEXTINPUTS}:@srcdir@" \
+		$(PDFLATEX) $< > /dev/null; \
+	  if [ x'$(AM_V_at)' = x ]; then \
+	    echo TEXINPUTS="$${TEXTINPUTS}:@srcdir@" \
+		SOURCE_DATE_EPOCH=$(SOURCE_DATE_EPOCH)  \
+		$(PDFLATEX) $< ; \
+	  fi ; \
+	  TEXINPUTS="$${TEXTINPUTS}:@srcdir@" \
 		SOURCE_DATE_EPOCH=$(SOURCE_DATE_EPOCH)  \
-		$(PDFLATEX) yaws.tex > /dev/null
+		$(PDFLATEX) $< > /dev/null; \
+	else \
+	  if [ x'$(AM_V_GEN)' != x ]; then \
+	    echo '  $(PDFLATEX)  $<' ; \
+	  else \
+	    echo TEXINPUTS="$${TEXTINPUTS}:@srcdir@" \
+		$(PDFLATEX) $< ; \
+	  fi ; \
+	  TEXINPUTS="$${TEXTINPUTS}:@srcdir@" \
+		$(PDFLATEX) $< > /dev/null; \
+	  if [ x'$(AM_V_at)' = x ]; then \
+	    echo TEXINPUTS="$${TEXTINPUTS}:@srcdir@" \
+		$(PDFLATEX) $< ; \
+	  fi ; \
+	  TEXINPUTS="$${TEXTINPUTS}:@srcdir@" \
+		$(PDFLATEX) $< > /dev/null; \
+	fi
 
 yaws.dvi: yaws.tex $(IMG_EPS)
-	$(AM_V_GEN)TEXINPUTS="$${TEXTINPUTS}:@srcdir@" \
+	@if [ x"$(SOURCE_DATE_EPOCH)" != x ]; then \
+	  if [ x'$(AM_V_at)' = x ]; then \
+	    echo TEXINPUTS="$${TEXTINPUTS}:@srcdir@" \
 		SOURCE_DATE_EPOCH=$(SOURCE_DATE_EPOCH) \
-		$(DVILATEX) yaws.tex > /dev/null
-	$(AM_V_at)TEXINPUTS="$${TEXTINPUTS}:@srcdir@" \
+		$(DVILATEX) $< ; \
+	  fi ; \
+	  TEXINPUTS="$${TEXTINPUTS}:@srcdir@" \
 		SOURCE_DATE_EPOCH=$(SOURCE_DATE_EPOCH) \
-		$(DVILATEX) yaws.tex > /dev/null
+		$(DVILATEX) $< > /dev/null; \
+	else \
+	  if [ x'$(AM_V_at)' = x ]; then \
+	    echo TEXINPUTS="$${TEXTINPUTS}:@srcdir@" \
+		$(DVILATEX) $< ; \
+	  fi ; \
+	  TEXINPUTS="$${TEXTINPUTS}:@srcdir@" \
+		$(DVILATEX) $< > /dev/null; \
+	fi
 
 .eps.pdf:
-	$(AM_V_GEN)SOURCE_DATE_EPOCH=$(SOURCE_DATE_EPOCH) \
-		$(EPSTOPDF) --outfile=$@ $< > /dev/null
+	@if [ x"$(SOURCE_DATE_EPOCH)" != x ]; then \
+	  if [ x'$(AM_V_at)' = x ]; then \
+	    echo SOURCE_DATE_EPOCH=$(SOURCE_DATE_EPOCH) \
+		$(EPSTOPDF) --outfile=$@ $< ; \
+	  fi ; \
+	  SOURCE_DATE_EPOCH=$(SOURCE_DATE_EPOCH) \
+		$(EPSTOPDF) --outfile=$@ $< > /dev/null; \
+	else \
+	  if [ x'$(AM_V_at)' = x ]; then \
+	    echo $(EPSTOPDF) --outfile=$@ $< ; \
+	  fi ; \
+	  $(EPSTOPDF) --outfile=$@ $< > /dev/null; \
+	fi
 
 .NOTPARALLEL:
 # Local Variables: