Abort upgrades upon user interrupt

Closes gh-39685

Author: wilkinsona

buildSrc/src/main/java/org/springframework/boot/build/bom/bomr/InteractiveUpgradeResolver.java

@@ -18,6 +18,7 @@
 
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -52,7 +53,12 @@ public List<Upgrade> resolveUpgrades(Collection<Library> librariesToUpgrade, Col
 		}
 		List<LibraryWithVersionOptions> libraryUpdates = this.libraryUpdateResolver
 			.findLibraryUpdates(librariesToUpgrade, librariesByName);
-		return libraryUpdates.stream().map(this::resolveUpgrade).filter(Objects::nonNull).toList();
+		try {
+			return libraryUpdates.stream().map(this::resolveUpgrade).filter(Objects::nonNull).toList();
+		}
+		catch (UpgradesInterruptedException ex) {
+			return Collections.emptyList();
+		}
 	}
 
 	private Upgrade resolveUpgrade(LibraryWithVersionOptions libraryWithVersionOptions) {
@@ -69,8 +75,15 @@ private Upgrade resolveUpgrade(LibraryWithVersionOptions libraryWithVersionOptio
 			options.addAll(libraryWithVersionOptions.getVersionOptions());
 			return questions.selectOption(question, options, defaultOption);
 		}).get();
+		if (this.userInputHandler.interrupted()) {
+			throw new UpgradesInterruptedException();
+		}
 		return (selected.equals(defaultOption)) ? null
 				: new Upgrade(libraryWithVersionOptions.getLibrary(), selected.getVersion());
 	}
 
+	static class UpgradesInterruptedException extends RuntimeException {
+
+	}
+
 }