[PATCH cygport] Add more checks of SOURCE_DATE_EPOCH

[Christian Franke via Cygwin-apps]

From b04c8f5e9becd6e91095e2add551f72870c9e869 Mon Sep 17 00:00:00 2001
From: Christian Franke <christian.fra...@t-online.de>
Date: Fri, 16 Feb 2024 13:16:06 +0100
Subject: [PATCH] Add more checks of SOURCE_DATE_EPOCH

Fail if it is out of range.  Warn if it lies in the future.
Inform whether it is set or set but not exported.
---
 bin/cygport.in | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/bin/cygport.in b/bin/cygport.in
index 5fc89eaf..3fe8a52e 100755
--- a/bin/cygport.in
+++ b/bin/cygport.in
@@ -493,14 +493,32 @@ unset restrict
 
 if [ "${SOURCE_DATE_EPOCH+y}" = "y" ]
 then
-       if [ -n "$(echo "${SOURCE_DATE_EPOCH}" | sed -e 's/^$/X/' -e 
's/[0-9]//g')" ]
+       if ! [[ "${SOURCE_DATE_EPOCH}" =~ ^[0-9]+$ ]]
        then
                error "SOURCE_DATE_EPOCH must be an integer number (seconds 
since the unix epoch)"
        fi
+       if ! _d=$(date --iso-8601=seconds -d "@${SOURCE_DATE_EPOCH}" 
2>/dev/null)
+       then
+               error "SOURCE_DATE_EPOCH is out of range"
+       fi
+       if [ "${SOURCE_DATE_EPOCH}" -le "$(printf '%(%s)T')" ]
+       then
+               inform "Reproducible build: 
SOURCE_DATE_EPOCH='${SOURCE_DATE_EPOCH}' [$_d]"
+       else
+               warning "SOURCE_DATE_EPOCH='${SOURCE_DATE_EPOCH}' [$_d] lies in 
the future"
+       fi
+       unset _d
+       if [ -z "$(printenv SOURCE_DATE_EPOCH 2>/dev/null)" ]
+       then
+               inform "SOURCE_DATE_EPOCH is not exported to the environment"
+       fi
+
        case $(peflags --version 2>/dev/null | sed -n '1s/^.* //p') in
                4.6.[6-9]|4.[7-9]*|[5-9]*) ;;
                *) error "SOURCE_DATE_EPOCH requires peflags 4.6.6 or later"
        esac
+else
+       inform "SOURCE_DATE_EPOCH is not set"
 fi
 
 
-- 
2.43.0