Merge pull request #214438 from agbrooks/master

dockerTools.buildImage: Handle base images w/ duplicate rootfs diffs

1 files changed, 11 insertions, 1 deletions

diff --git a/pkgs/build-support/docker/default.nix b/pkgs/build-support/docker/default.nix
index bdc93f3643f10..7fa5aeafc8e3d 100644
--- a/pkgs/build-support/docker/default.nix
+++ b/pkgs/build-support/docker/default.nix
@@ -229,6 +229,15 @@ rec {
           mount /dev/${vmTools.hd} disk
           cd disk
 
+          function dedup() {
+            declare -A seen
+            while read ln; do
+              if [[ -z "''${seen["$ln"]:-}" ]]; then
+                echo "$ln"; seen["$ln"]=1
+              fi
+            done
+          }
+
           if [[ -n "$fromImage" ]]; then
             echo "Unpacking base image..."
             mkdir image
@@ -245,7 +254,8 @@ rec {
               parentID="$(cat "image/manifest.json" | jq -r '.[0].Config | rtrimstr(".json")')"
             fi
 
-            cat ./image/manifest.json  | jq -r '.[0].Layers | .[]' > layer-list
+            # In case of repeated layers, unpack only the last occurrence of each
+            cat ./image/manifest.json  | jq -r '.[0].Layers | .[]' | tac | dedup | tac > layer-list
           else
             touch layer-list
           fi