From c517652a0a9df27f209a593932bc48f27679af4a Mon Sep 17 00:00:00 2001
From: plk <Philip@kime.org.uk>
Date: Sun, 14 Apr 2024 16:07:39 +0200
Subject: [PATCH] Looking at #474

---
 bin/biber                |  9 +++++++++
 lib/Biber/Config.pm      |  9 ++++++---
 lib/Biber/Constants.pm   |  1 +
 lib/Biber/Output/base.pm | 10 ++++++++--
 4 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/bin/biber b/bin/biber
index fbcc1603a..ebd6098bd 100755
--- a/bin/biber
+++ b/bin/biber
@@ -20,6 +20,7 @@ use Encode;
 use File::Spec;
 use Pod::Usage;
 use List::AllUtils qw( first );
+use Unicode::Normalize qw(NFC);
 
 use Getopt::Long qw/:config no_ignore_case/;
 my $opts = {};
@@ -341,6 +342,14 @@ $logfile->info("=== $time_string");
 
 my $bcf = Biber::Config->getoption('bcf');
 
+# Determine the input Unicode form so we can make sure output filenames are the
+# same format
+if ($bcf eq NFC($bcf)) {
+    Biber::Config->setoption('UFORM', 'NFC');
+} else {
+    Biber::Config->setoption('UFORM', 'NFD');
+}
+
 if (Biber::Config->getoption('output_file')) {
   $outfile = Biber::Config->getoption('output_file')
 }
diff --git a/lib/Biber/Config.pm b/lib/Biber/Config.pm
index e99fe1be9..d8c98e89c 100644
--- a/lib/Biber/Config.pm
+++ b/lib/Biber/Config.pm
@@ -18,7 +18,7 @@ use Log::Log4perl::Appender::Screen;
 use Log::Log4perl::Appender::File;
 use Log::Log4perl::Layout::SimpleLayout;
 use Log::Log4perl::Layout::PatternLayout;
-use Unicode::Normalize;
+use Unicode::Normalize qw(normalize NFC NFD);
 use parent qw(Class::Accessor);
 __PACKAGE__->follow_best_practice;
 
@@ -224,8 +224,11 @@ sub _initopts {
     }
   }
 
-  # Sanitse log file name to NFC
-  $biberlog = NFC($biberlog);
+  # Sanitise log file name to the same as the input .bcf
+  if ($biberlog) {
+    $biberlog = normalize('NFD', $biberlog);
+    #    $biberlog = normalize(Biber::Config->getoption('UFORM'), $biberlog);
+  }
 
   # cache meta markers since they are referenced in the oft-called _get_handler
   $CONFIG_META_MARKERS{annotation} = quotemeta(Biber::Config->getoption('annotation_marker'));
diff --git a/lib/Biber/Constants.pm b/lib/Biber/Constants.pm
index ef4dafc55..6dad80a24 100644
--- a/lib/Biber/Constants.pm
+++ b/lib/Biber/Constants.pm
@@ -311,6 +311,7 @@ our $CONFIG_DEFAULT_BIBER = {
   xdatasep                                    => { content => '-' },
   xnamesep                                    => { content => '=' },
   xsvsep                                      => { content => q/\s*,\s*/ },
+  UFORM                                       => { content => 'NFC' }
 };
 
 # Set up some re-usable CSV parsers here for efficiency reasons
diff --git a/lib/Biber/Output/base.pm b/lib/Biber/Output/base.pm
index 7b03b150a..989ab95b3 100644
--- a/lib/Biber/Output/base.pm
+++ b/lib/Biber/Output/base.pm
@@ -10,7 +10,7 @@ use IO::File;
 use Text::Wrap;
 $Text::Wrap::columns = 80;
 use Log::Log4perl qw( :no_extra_logdie_message );
-use Unicode::Normalize;
+use Unicode::Normalize qw(normalize NFC NFD);
 my $logger = Log::Log4perl::get_logger('main');
 
 =encoding utf-8
@@ -60,7 +60,13 @@ sub set_output_target_file {
   if (my $enc = Biber::Config->getoption('output_encoding')) {
     $enc_out = ":encoding($enc)";
   }
-  return IO::File->new($file, ">$enc_out");
+
+  if (ref($file) eq 'SCALAR') {
+    return IO::File->new($file, ">$enc_out");
+  }
+  else {
+    return IO::File->new(normalize(Biber::Config->getoption('UFORM'), $file), ">$enc_out");
+  }
 }
 
 =head2 get_output_target_file