Manifest generation: fail on write errors, clean up logging

- ManifestGenerator: throw DeepLinkProcessorException on IOException
  instead of swallowing as a diagnostic warning (a missing manifest
  would otherwise fail silently in a confusing downstream place).
  Catch scoped to IOException so processor bugs aren't hidden.
- RelocateDeepLinkManifestTask: use orNull instead of get() on the
  @optional kspManifestFile property (get() NPEs when unset), replace
  println with logger.warn, collapse empty else-if branch, fix typos.
- GenerateManifestIntentFiltersForDeeplinkDispatchTask: replace
  println with logger.warn (respects --quiet) and switch error(...)
  calls to throw GradleException for idiomatic build-failure output.

Author: Andreas Rossbacher

deeplinkdispatch-gradle-plugin/src/main/java/com/airbnb/deeplinkdispatch/gradleplugin/GenerateManifestIntentFiltersForDeeplinkDispatchTask.kt

@@ -5,6 +5,7 @@ import com.android.manifmerger.ManifestMerger2
 import com.android.manifmerger.MergingReport
 import com.android.utils.StdLogger
 import org.gradle.api.DefaultTask
+import org.gradle.api.GradleException
 import org.gradle.api.file.DirectoryProperty
 import org.gradle.api.file.RegularFileProperty
 import org.gradle.api.provider.Property
@@ -82,12 +83,12 @@ abstract class GenerateManifestIntentFiltersForDeeplinkDispatchTask : DefaultTas
             generatedManifestFile.length() > 0
 
         if (!hasGeneratedManifest) {
-            println(
+            logger.warn(
                 "No DeepLinkDispatch generated manifest found or manifest is empty. Copying input" +
-                        " manifest to output without modifications. You might have applied the" +
-                        " deep link dispatch gradle plugin to a module that does not have deep" +
-                        " links defined or you forgot the set the `activityClassFqn` on your deep" +
-                        " links."
+                    " manifest to output without modifications. You might have applied the" +
+                    " deep link dispatch gradle plugin to a module that does not have deep" +
+                    " links defined or you forgot to set the `activityClassFqn` on your deep" +
+                    " links.",
             )
             inputManifest.copyTo(outputManifest, overwrite = true)
             return
@@ -112,7 +113,7 @@ abstract class GenerateManifestIntentFiltersForDeeplinkDispatchTask : DefaultTas
         val merge = invoker.merge()
         if (merge.result.isSuccess) {
             val mergedDocument = merge.getMergedDocument(MergingReport.MergedManifestKind.MERGED)
-                ?: error("Failed to get merged document")
+                ?: throw GradleException("DeepLinkDispatch: failed to get merged manifest document")
             outputManifest.writeText(mergedDocument)
         } else {
             val errorMessage = buildString {
@@ -121,7 +122,7 @@ abstract class GenerateManifestIntentFiltersForDeeplinkDispatchTask : DefaultTas
                     appendLine("  ${record.severity}: ${record.message}")
                 }
             }
-            error(errorMessage)
+            throw GradleException(errorMessage)
         }
     }
 

deeplinkdispatch-gradle-plugin/src/main/java/com/airbnb/deeplinkdispatch/gradleplugin/RelocateDeepLinkManifestTask.kt

@@ -41,20 +41,18 @@ abstract class RelocateDeepLinkManifestTask : DefaultTask() {
         // 2. Gradle's up-to-date check only compares content, not file existence
         // 3. The task deletes the source file, which needs to happen every time
         outputs.upToDateWhen {
-            // Task is only up-to-date if source file doesn't exist
-            !kspManifestFile.get().asFile.exists()
+            val source = kspManifestFile.orNull?.asFile
+            source == null || !source.exists()
         }
     }
 
     @TaskAction
     fun taskAction() {
-        val sourceFile = kspManifestFile.get().asFile
+        val sourceFile = kspManifestFile.orNull?.asFile
         val destFile = safeManifestFile.get().asFile
 
-        if (sourceFile.exists()) {
-            // Ensure parent directory exists
+        if (sourceFile != null && sourceFile.exists()) {
             destFile.parentFile?.mkdirs()
-            // Copy to safe location
             sourceFile.copyTo(destFile, overwrite = true)
             // Delete from KSP resources to prevent Java resource merge conflict
             if (sourceFile.delete()) {
@@ -70,14 +68,13 @@ abstract class RelocateDeepLinkManifestTask : DefaultTask() {
                     parentDir = nextParent
                 }
             }
-        } else if (destFile.exists()) {
-            // Source doesn't exist but dest does - this can happen on incremental builds
-            // where KSP was UP-TO-DATE and we already moved the file previously.
-            // The dest file is still valid, so nothing to do.
-        } else {
-            // Neither file exists - no manifest was generated
-            println("No DeepLinkDispatch manifest found to relocate in ${project.name}. If this module has no deep links, consider" +
-                    "removing the DeepLinkDispatch gradle plugin from it's gradle file.")
+        } else if (!destFile.exists()) {
+            logger.warn(
+                "No DeepLinkDispatch manifest found to relocate in ${project.name}. " +
+                    "If this module has no deep links, consider removing the DeepLinkDispatch " +
+                    "gradle plugin from its gradle file.",
+            )
         }
+        // If source is gone but dest exists, a previous run already relocated it — nothing to do.
     }
 }

deeplinkdispatch-processor/src/main/java/com/airbnb/deeplinkdispatch/metadata/ManifestGenerator.kt

@@ -5,9 +5,11 @@ import androidx.room.compiler.processing.XFiler
 import androidx.room.compiler.processing.XMessager
 import androidx.room.compiler.processing.XProcessingEnv
 import com.airbnb.deeplinkdispatch.DeepLinkAnnotatedElement
+import com.airbnb.deeplinkdispatch.DeepLinkProcessorException
 import com.airbnb.deeplinkdispatch.base.ManifestGeneration
 import com.airbnb.deeplinkdispatch.metadata.writers.ManifestWriter
 import com.airbnb.deeplinkdispatch.metadata.writers.Writer
+import java.io.IOException
 import java.io.PrintWriter
 import java.io.StringWriter
 import java.nio.file.Path
@@ -108,10 +110,10 @@ internal class ManifestGenerator(
                 Diagnostic.Kind.NOTE,
                 "Manifest generation: Generated at KSP resource output: ${ManifestGeneration.MANIFEST_RESOURCE_PATH}",
             )
-        } catch (e: Exception) {
-            messager.printMessage(
-                Diagnostic.Kind.ERROR,
-                "Manifest generation failed: ${e.message}",
+        } catch (e: IOException) {
+            throw DeepLinkProcessorException(
+                "Manifest generation failed: could not write " +
+                    "${ManifestGeneration.MANIFEST_RESOURCE_PATH}: ${e.message}",
             )
         }
     }