git-svn-preserve-date-author-in-dcommit.patch

# Patch adapted from https://stackoverflow.com/a/36647984/12814490
# Tested on git-svn v2.17.1
# patch /usr/lib/git-core/git-svn git-svn-preserve-date-author-in-dcommit.patch
--- /usr/lib/git-core/git-svn.old	2020-01-28 18:48:56.729362630 +0100
+++ /usr/lib/git-core/git-svn	2020-01-30 16:08:24.240207858 +0100
@@ -17,6 +17,7 @@
 use File::Spec;
 use Getopt::Long qw/:config gnu_getopt no_ignore_case auto_abbrev/;
 use Memoize;
+use POSIX qw/strftime/;
 
 use Git::SVN;
 use Git::SVN::Editor;
@@ -969,6 +970,17 @@
 			}
 		}
 	}
+	
+	#Revert the keys/values from authors into a reverse map.
+	#If a duplicate is found(i.e. 2 git users matching 1 svn user) abort the operation.
+	my %rev_author_map;
+	while (my ($key, @value) = each %users) {
+		my $rev_key="$value[0][0] <$value[0][1]>";
+		if(exists $rev_author_map{$rev_key}) {
+			fatal "Found a duplicate GIT author($rev_key) in the authorsfile. Aborting dcommit!"
+		}
+		$rev_author_map{$rev_key}=$key
+	}
 
 	my $rewritten_parent;
 	my $current_head = command_oneline(qw/rev-parse HEAD/);
@@ -985,6 +997,20 @@
 				      "from commit $d~1";
 			}
 		}
+		my $commit_entry = get_commit_entry($d);
+		my $cmt_author = $commit_entry->{author};
+		my $cmt_date = $commit_entry->{date};
+		my $formatted_cmt_date = Git::SVN::Log::format_svn_date($cmt_date);
+		print "GIT DATE: $formatted_cmt_date; \n";
+		print "GIT AUTHOR: $cmt_author; \n";
+		if(defined $cmt_author) {
+			my $svn_author = $rev_author_map{$cmt_author};
+			#Here we check if the git commit author matches an author in the authorsfile
+			if ((not (defined $svn_author)) || $svn_author eq "") {
+				fatal "The git author: $cmt_author was not found in the authors file. Make sure you have commited as a user listed in the authors file. Note:matching is case sensitive.";
+			}
+			print "SVN AUTHOR: $svn_author\n";
+		}
 		if ($_dry_run) {
 			print "diff-tree $d~1 $d\n";
 		} else {
@@ -996,10 +1022,11 @@
 				                             $linear_refs,
 				                             $rewritten_parent);
 			}
-
+			
+			my $ra = Git::SVN::Ra->new($url);
 			my %ed_opts = ( r => $last_rev,
-			                log => get_commit_entry($d)->{log},
-			                ra => Git::SVN::Ra->new($url),
+			                log => $commit_entry->{log},
+			                ra => $ra,
 			                config => SVN::Core::config_get_config(
 			                        $Git::SVN::Ra::config_dir
 			                ),
@@ -1025,6 +1052,20 @@
 				$gs->{inject_parents_dcommit}->{$cmt_rev} =
 				                               $parents->{$d};
 			}
+			
+			#Here we coerce SVN into accepting the correct user according to the reverse mapping.
+			if(defined $cmt_author) {
+				my $svn_author = $rev_author_map{$cmt_author};
+				print "SVN AUTHOR: $svn_author\n";
+				$ra->change_rev_prop($cmt_rev, 'svn:author', $svn_author)
+			}
+			#Here we coerce SVN into accepting the commit date from Git.
+			if ( defined $cmt_date ) {
+				$cmt_date = strftime("%Y-%m-%dT%H:%M:%S.000000Z", gmtime($cmt_date));
+				print "SVN DATE SET TO: $cmt_date\n";
+				$ra->change_rev_prop($cmt_rev, 'svn:date', $cmt_date);
+			}
+			
 			$_fetch_all ? $gs->fetch_all : $gs->fetch;
 			$SVN::Error::handler = $err_handler;
 			$last_rev = $cmt_rev;
@@ -1842,7 +1883,7 @@
 
 sub get_commit_entry {
 	my ($treeish) = shift;
-	my %log_entry = ( log => '', tree => get_tree_from_treeish($treeish) );
+	my %log_entry = ( log => '', tree => get_tree_from_treeish($treeish), author =>undef, date => undef );
 	my @git_path = qw(rev-parse --git-path);
 	my $commit_editmsg = command_oneline(@git_path, 'COMMIT_EDITMSG');
 	my $commit_msg = command_oneline(@git_path, 'COMMIT_MSG');
@@ -1859,7 +1900,11 @@
 		while (<$msg_fh>) {
 			if (!$in_msg) {
 				$in_msg = 1 if (/^$/);
-				$author = $1 if (/^author (.*>)/);
+				if (/^author (.*>) (\d+) ([\-\+]?\d+)$/o) {
+					$author = $1;
+					$log_entry{author} = $1;
+					$log_entry{date} = $2;
+				}
 			} elsif (/^git-svn-id: /) {
 				# skip this for now, we regenerate the
 				# correct one on re-fetch anyways