git-svn log: handle unreachable revisions like "svn log"

When unreachable revisions are given to "svn log", it displays all commit
logs in the given range that exist in the current tree.  (If no commit
logs are found in the current tree, it simply prints a single commit log
separator.)  This patch makes "git-svn log" behave the same way.

Ten tests added to t/t9116-git-svn-log.sh.

Signed-off-by: David D Kilzer <ddkilzer@kilzer.net>
Acked-by: Eric Wong <normalperson@yhbt.net>

git-svn.perl

@@ -2399,10 +2399,15 @@ sub rev_db_get {
 	$ret;
 }
 
+# Finds the first svn revision that exists on (if $eq_ok is true) or
+# before $rev for the current branch.  It will not search any lower
+# than $min_rev.  Returns the git commit hash and svn revision number
+# if found, else (undef, undef).
 sub find_rev_before {
-	my ($self, $rev, $eq_ok) = @_;
+	my ($self, $rev, $eq_ok, $min_rev) = @_;
 	--$rev unless $eq_ok;
-	while ($rev > 0) {
+	$min_rev ||= 1;
+	while ($rev >= $min_rev) {
 		if (my $c = $self->rev_db_get($rev)) {
 			return ($rev, $c);
 		}
@@ -2411,6 +2416,23 @@ sub find_rev_before {
 	return (undef, undef);
 }
 
+# Finds the first svn revision that exists on (if $eq_ok is true) or
+# after $rev for the current branch.  It will not search any higher
+# than $max_rev.  Returns the git commit hash and svn revision number
+# if found, else (undef, undef).
+sub find_rev_after {
+	my ($self, $rev, $eq_ok, $max_rev) = @_;
+	++$rev unless $eq_ok;
+	$max_rev ||= $self->rev_db_max();
+	while ($rev <= $max_rev) {
+		if (my $c = $self->rev_db_get($rev)) {
+			return ($rev, $c);
+		}
+		++$rev;
+	}
+	return (undef, undef);
+}
+
 sub _new {
 	my ($class, $repo_id, $ref_id, $path) = @_;
 	unless (defined $repo_id && length $repo_id) {
@@ -3701,6 +3723,7 @@ package Git::SVN::Log;
 use strict;
 use warnings;
 use POSIX qw/strftime/;
+use constant commit_log_separator => ('-' x 72) . "\n";
 use vars qw/$TZ $limit $color $pager $non_recursive $verbose $oneline
             %rusers $show_commit $incremental/;
 my $l_fmt;
@@ -3794,19 +3817,19 @@ sub git_svn_log_cmd {
 			push @cmd, $c;
 		}
 	} elsif (defined $r_max) {
-		my ($c_min, $c_max);
-		$c_max = $gs->rev_db_get($r_max);
-		$c_min = $gs->rev_db_get($r_min);
-		if (defined $c_min && defined $c_max) {
-			if ($r_max > $r_min) {
-				push @cmd, "--boundary", "$c_min..$c_max";
-			} else {
-				push @cmd, "--boundary", "$c_max..$c_min";
-			}
-		} elsif ($r_max > $r_min) {
-			push @cmd, $c_max;
+		if ($r_max < $r_min) {
+			($r_min, $r_max) = ($r_max, $r_min);
+		}
+		my (undef, $c_max) = $gs->find_rev_before($r_max, 1, $r_min);
+		my (undef, $c_min) = $gs->find_rev_after($r_min, 1, $r_max);
+		# If there are no commits in the range, both $c_max and $c_min
+		# will be undefined.  If there is at least 1 commit in the
+		# range, both will be defined.
+		return () if !defined $c_min || !defined $c_max;
+		if ($c_min eq $c_max) {
+			push @cmd, '--max-count=1', $c_min;
 		} else {
-			push @cmd, $c_min;
+			push @cmd, '--boundary', "$c_min..$c_max";
 		}
 	}
 	return (@cmd, @files);
@@ -3914,7 +3937,7 @@ sub show_commit_changed_paths {
 
 sub show_commit_normal {
 	my ($c) = @_;
-	print '-' x72, "\nr$c->{r} | ";
+	print commit_log_separator, "r$c->{r} | ";
 	print "$c->{c} | " if $show_commit;
 	print "$c->{a} | ", strftime("%Y-%m-%d %H:%M:%S %z (%a, %d %b %Y)",
 				 localtime($c->{t_utc})), ' | ';
@@ -3975,6 +3998,10 @@ sub cmd_show_log {
 
 	config_pager();
 	@args = git_svn_log_cmd($r_min, $r_max, @args);
+	if (!@args) {
+		print commit_log_separator unless $incremental || $oneline;
+		return;
+	}
 	my $log = command_output_pipe(@args);
 	run_pager();
 	my (@k, $c, $d, $stat);
@@ -4023,14 +4050,12 @@ sub cmd_show_log {
 		process_commit($c, $r_min, $r_max, \@k);
 	}
 	if (@k) {
-		my $swap = $r_max;
-		$r_max = $r_min;
-		$r_min = $swap;
+		($r_min, $r_max) = ($r_max, $r_min);
 		process_commit($_, $r_min, $r_max) foreach reverse @k;
 	}
 out:
 	close $log;
-	print '-' x72,"\n" unless $incremental || $oneline;
+	print commit_log_separator unless $incremental || $oneline;
 }
 
 package Git::SVN::Migration;

t/t9116-git-svn-log.sh

@@ -30,6 +30,12 @@ test_expect_success 'setup repository and import' "
 	git reset --hard trunk &&
 	echo aye >> README &&
 	git commit -a -m aye &&
+	git svn dcommit &&
+	git reset --hard b &&
+	echo spy >> README &&
+	git commit -a -m spy &&
+	echo try >> README &&
+	git commit -a -m try &&
 	git svn dcommit
 	"
 
@@ -59,4 +65,64 @@ test_expect_success 'test descending revision range' "
 	git svn log -r 4:1 | grep '^r[0-9]' | cut -d'|' -f1 | diff -u expected-range-r4-r2-r1 -
 	"
 
+printf 'r1 \nr2 \n' > expected-range-r1-r2
+
+test_expect_success 'test ascending revision range with unreachable revision' "
+	git reset --hard trunk &&
+	git svn log -r 1:3 | grep '^r[0-9]' | cut -d'|' -f1 | diff -u expected-range-r1-r2 -
+	"
+
+printf 'r2 \nr1 \n' > expected-range-r2-r1
+
+test_expect_success 'test descending revision range with unreachable revision' "
+	git reset --hard trunk &&
+	git svn log -r 3:1 | grep '^r[0-9]' | cut -d'|' -f1 | diff -u expected-range-r2-r1 -
+	"
+
+printf 'r2 \n' > expected-range-r2
+
+test_expect_success 'test ascending revision range with unreachable upper boundary revision and 1 commit' "
+	git reset --hard trunk &&
+	git svn log -r 2:3 | grep '^r[0-9]' | cut -d'|' -f1 | diff -u expected-range-r2 -
+	"
+
+test_expect_success 'test descending revision range with unreachable upper boundary revision and 1 commit' "
+	git reset --hard trunk &&
+	git svn log -r 3:2 | grep '^r[0-9]' | cut -d'|' -f1 | diff -u expected-range-r2 -
+	"
+
+printf 'r4 \n' > expected-range-r4
+
+test_expect_success 'test ascending revision range with unreachable lower boundary revision and 1 commit' "
+	git reset --hard trunk &&
+	git svn log -r 3:4 | grep '^r[0-9]' | cut -d'|' -f1 | diff -u expected-range-r4 -
+	"
+
+test_expect_success 'test descending revision range with unreachable lower boundary revision and 1 commit' "
+	git reset --hard trunk &&
+	git svn log -r 4:3 | grep '^r[0-9]' | cut -d'|' -f1 | diff -u expected-range-r4 -
+	"
+
+printf -- '------------------------------------------------------------------------\n' > expected-separator
+
+test_expect_success 'test ascending revision range with unreachable boundary revisions and no commits' "
+	git reset --hard trunk &&
+	git svn log -r 5:6 | diff -u expected-separator -
+	"
+
+test_expect_success 'test descending revision range with unreachable boundary revisions and no commits' "
+	git reset --hard trunk &&
+	git svn log -r 6:5 | diff -u expected-separator -
+	"
+
+test_expect_success 'test ascending revision range with unreachable boundary revisions and 1 commit' "
+	git reset --hard trunk &&
+	git svn log -r 3:5 | grep '^r[0-9]' | cut -d'|' -f1 | diff -u expected-range-r4 -
+	"
+
+test_expect_success 'test descending revision range with unreachable boundary revisions and 1 commit' "
+	git reset --hard trunk &&
+	git svn log -r 5:3 | grep '^r[0-9]' | cut -d'|' -f1 | diff -u expected-range-r4 -
+	"
+
 test_done