OciImagesInputTask: add warning for duplicate non-empty layers

SgtSilvio · May 8, 2024 · ea9fd0b · ea9fd0b
1 parent 121b689
commit ea9fd0b
Showing 1 changed file with 20 additions and 6 deletions.
diff --git a/src/main/kotlin/io/github/sgtsilvio/gradle/oci/OciImagesInput.kt b/src/main/kotlin/io/github/sgtsilvio/gradle/oci/OciImagesInput.kt
@@ -2,10 +2,7 @@ package io.github.sgtsilvio.gradle.oci
 
 import io.github.sgtsilvio.gradle.oci.component.*
 import io.github.sgtsilvio.gradle.oci.dsl.ResolvableOciImageDependencies
-import io.github.sgtsilvio.gradle.oci.metadata.OciDigest
-import io.github.sgtsilvio.gradle.oci.metadata.OciDigestAlgorithm
-import io.github.sgtsilvio.gradle.oci.metadata.OciImageReference
-import io.github.sgtsilvio.gradle.oci.metadata.calculateOciDigests
+import io.github.sgtsilvio.gradle.oci.metadata.*
 import org.apache.commons.io.FileUtils
 import org.gradle.api.DefaultTask
 import org.gradle.api.NonExtensible
@@ -57,8 +54,8 @@ abstract class OciImagesInputTask : DefaultTask() {
             }
             for ((layerDescriptor, layer) in layers) {
                 val prevLayer = digestToLayer.putIfAbsent(layerDescriptor.digest, layer)
-                if ((prevLayer != null) && (prevLayer != layer) && !FileUtils.contentEquals(prevLayer, layer)) {
-                    throw IllegalStateException("hash collision for digest ${layerDescriptor.digest}: expected file contents of $prevLayer and $layer to be the same")
+                if (prevLayer != null) {
+                    checkDuplicateLayer(layerDescriptor, prevLayer, layer)
                 }
             }
             for ((rootCapability, references) in imagesInput.rootCapabilities.get()) {
@@ -212,4 +209,21 @@ abstract class OciImagesInputTask : DefaultTask() {
             }
         }
     }
+
+    private fun checkDuplicateLayer(layerDescriptor: OciComponent.Bundle.Layer.Descriptor, file1: File, file2: File) {
+        if (file1 != file2) {
+            if (!FileUtils.contentEquals(file1, file2)) {
+                throw IllegalStateException("hash collision for digest ${layerDescriptor.digest}: expected file contents of $file1 and $file2 to be the same")
+            }
+            if (layerDescriptor.diffId !in EMPTY_LAYER_DIFF_IDS) {
+                logger.warn("the same layer (${layerDescriptor.digest}) should not be provided by multiple artifacts ($file1, $file2)")
+            }
+        }
+    }
 }
+
+// empty tar = 1024 bytes zeros
+private val EMPTY_LAYER_DIFF_IDS = setOf(
+    "sha256:5f70bf18a086007016e948b04aed3b82103a36bea41755b6cddfaf10ace3c6ef".toOciDigest(),
+    "sha512:8efb4f73c5655351c444eb109230c556d39e2c7624e9c11abc9e3fb4b9b9254218cc5085b454a9698d085cfa92198491f07a723be4574adc70617b73eb0b6461".toOciDigest(),
+)