mirror-nixos-branch: also expose date of commit

emilylange · emilylange · commit 30efa0ad83c0 · 2025-11-13T21:18:22.000+01:00
This is both very useful when viewing the summary html page on
releases.nixos.org (via channels.nixos.org) and also makes it so when
using the nixexprs.tar.xz as flake input, the flake metadata shows the
same date as the equivalent github:NixOS/nixpkgs would yield, instead of
relying on whatever the newest lastMod of any file in the tarball is.
diff --git a/mirror-nixos-branch.pl b/mirror-nixos-branch.pl
@@ -107,8 +107,12 @@ sub fetch {
 
 my $rev = $evalInfo->{jobsetevalinputs}->{nixpkgs}->{revision} or die;
 
+# Get commit date of $rev as unixtime and formatted string
+my $revUnix = `git show --no-patch --format='%ct' $rev` or die;
+my $revDate = strftime("%F %T", localtime($revUnix));
+
 print STDERR "\nRelease information:\n";
-print STDERR " - release is: $releaseName (build $releaseId)\n - eval is: $evalId\n - prefix is: $releasePrefix\n - Git commit is: $rev\n\n";
+print STDERR " - release is: $releaseName (build $releaseId)\n - eval is: $evalId\n - prefix is: $releasePrefix\n - Git commit is: $rev\n - Git commit date is: $revDate\n\n";
 
 if ($bucketChannels) {
     # Guard against the channel going back in time.
@@ -280,7 +284,7 @@ sub fetch {
     my $html = "<html><head>";
     $html .= "<title>$title</title></head>";
     $html .= "<body><h1>$title</h1>";
-    $html .= "<p>Released on $now from <a href='$githubLink'>Git commit <tt>$rev</tt></a> ";
+    $html .= "<p>Released on $now from <a href='$githubLink'>Git commit <tt>$rev</tt></a> from $revDate ";
     $html .= "via <a href='$evalUrl'>Hydra evaluation $evalId</a>.</p>";
     $html .= "<table><thead><tr><th>File name</th><th>Size</th><th>SHA-256 hash</th></tr></thead><tbody>";
 
@@ -357,7 +361,7 @@ sub redirect {
 
 # Update channels on channels.nixos.org.
 redirect($channelName, $releasePrefix);
-redirect("$channelName/nixexprs.tar.xz", "$releasePrefix/nixexprs.tar.xz?rev=$rev");
+redirect("$channelName/nixexprs.tar.xz", "$releasePrefix/nixexprs.tar.xz?rev=$rev&lastModified=$revUnix");
 redirect("$channelName/git-revision", "$releasePrefix/git-revision");
 redirect("$channelName/packages.json.br", "$releasePrefix/packages.json.br");
 redirect("$channelName/store-paths.xz", "$releasePrefix/store-paths.xz");
