diff --git a/src/lib/Hydra/Helper/AddBuilds.pm b/src/lib/Hydra/Helper/AddBuilds.pm
index 0bd0181d..1fc6adf2 100644
--- a/src/lib/Hydra/Helper/AddBuilds.pm
+++ b/src/lib/Hydra/Helper/AddBuilds.pm
@@ -64,7 +64,8 @@ sub updateDeclarativeJobset {
     $db->txn_do(sub {
         my $jobset = $project->jobsets->update_or_create(\%update);
         $jobset->jobsetinputs->delete;
-        while ((my $name, my $data) = each %{$declSpec->{"inputs"}}) {
+        foreach my $name (keys %{$declSpec->{"inputs"}}) {
+            my $data = $declSpec->{"inputs"}{$name};
             my $row = {
                 name => $name,
                 type => $data->{type}
@@ -84,7 +85,8 @@ sub handleDeclarativeJobsetJson {
             my @kept = keys %$declSpec;
             push @kept, ".jobsets";
             $project->jobsets->search({ name => { "not in" => \@kept } })->update({ enabled => 0, hidden => 1 });
-            while ((my $jobsetName, my $spec) = each %$declSpec) {
+            foreach my $jobsetName (keys %$declSpec) {
+                my $spec = $declSpec{$jobsetName};
                 eval {
                     updateDeclarativeJobset($db, $project, $jobsetName, $spec);
                     1;
diff --git a/src/lib/Hydra/Plugin/GitInput.pm b/src/lib/Hydra/Plugin/GitInput.pm
index 39a5cf83..02aa430d 100644
--- a/src/lib/Hydra/Plugin/GitInput.pm
+++ b/src/lib/Hydra/Plugin/GitInput.pm
@@ -118,7 +118,8 @@ sub fetchInput {
                             $jobset->get_column('name'),
                             $name);
     # give preference to the options from the input value
-    while (my ($opt_name, $opt_value) = each %{$options}) {
+    foreach my $opt_name (keys %{$options}) {
+        my $opt_value = $options{$opt_name};
         if ($opt_value =~ /^[+-]?\d+\z/) {
             $opt_value = int($opt_value);
         }
diff --git a/src/lib/Hydra/Plugin/S3Backup.pm b/src/lib/Hydra/Plugin/S3Backup.pm
index a67082ec..98e79747 100644
--- a/src/lib/Hydra/Plugin/S3Backup.pm
+++ b/src/lib/Hydra/Plugin/S3Backup.pm
@@ -98,7 +98,8 @@ sub buildFinished {
         foreach my $reference (@{$refs}) {
             push @needed_paths, $reference;
         }
-        while (my ($compression_type, $configs) = each %compression_types) {
+        foreach my $compression_type (keys %compression_types) {
+            my $configs = $compression_types{$compression_type};
             my @incomplete_buckets = ();
             # Don't do any work if all the buckets have this path
             foreach my $bucket_config (@{$configs}) {
@@ -144,7 +145,8 @@ sub buildFinished {
     }
 
     # Upload narinfos
-    while (my ($compression_type, $infos) = each %narinfos) {
+    foreach my $compression_type (keys %narinfos) {
+        my $infos = $narinfos{$compression_type};
         foreach my $bucket_config (@{$compression_types{$compression_type}}) {
             foreach my $info (@{$infos}) {
                 my $bucket = $client->bucket( name => $bucket_config->{name} );
diff --git a/src/script/hydra-eval-jobset b/src/script/hydra-eval-jobset
index 14f4467e..c61ce226 100755
--- a/src/script/hydra-eval-jobset
+++ b/src/script/hydra-eval-jobset
@@ -753,7 +753,8 @@ sub checkJobsetWrapped {
 
         if ($jobsetChanged) {
             # Create JobsetEvalMembers mappings.
-            while (my ($id, $x) = each %buildMap) {
+            foreach my $id (keys %buildMap) {
+                my $x = $buildMap{$id};
                 $ev->jobsetevalmembers->create({ build => $id, isnew => $x->{new} });
             }
 
@@ -762,7 +763,8 @@ sub checkJobsetWrapped {
             # builds for the same derivation, pick the one with the
             # shortest name.
             my %drvPathToId;
-            while (my ($id, $x) = each %buildMap) {
+            foreach my $id (keys %buildMap) {
+                my $x = $buildMap{$id};
                 my $y = $drvPathToId{$x->{drvPath}};
                 if (defined $y) {
                     next if length $x->{jobName} > length $y->{jobName};
@@ -806,7 +808,8 @@ sub checkJobsetWrapped {
 
             # Wake up hydra-queue-runner.
             my $lowestId;
-            while (my ($id, $x) = each %buildMap) {
+            foreach my $id (keys %buildMap) {
+                my $x = $buildMap{$id};
                 $lowestId = $id if $x->{new} && (!defined $lowestId || $id < $lowestId);
             }
             $notifyAdded->execute($lowestId) if defined $lowestId;