"pub cache repair" prints a more detailed summary.

lib/src/command/cache_repair.dart

Index: lib/src/command/cache_repair.dart
diff --git a/lib/src/command/cache_repair.dart b/lib/src/command/cache_repair.dart
index 3e130e96904d6fa468a57b15a94a7f4011335d51..53b0f0211e7705d6b4f00b8baa883219f78c5f8d 100644
--- a/lib/src/command/cache_repair.dart
+++ b/lib/src/command/cache_repair.dart
@@ -22,43 +22,58 @@ class CacheRepairCommand extends PubCommand {
   bool get takesArguments => false;
 
   Future run() async {
-    var successes = 0;
-    var failures = 0;
+    var successes = [];
+    var failures = [];
 
     // Repair every cached source.
     for (var source in cache.sources) {
       if (source is! CachedSource) continue;
 
       var results = await source.repairCachedPackages();
-      successes += results.first;
-      failures += results.last;
+      successes.addAll(results.first);
+      failures.addAll(results.last);
     }
 
-    if (successes > 0) {
-      var packages = pluralize("package", successes);
-      log.message("Reinstalled ${log.green(successes)} $packages.");
+    if (successes.length > 0) {
+      var packages = pluralize("package", successes.length);
+      log.message("Reinstalled ${log.green(successes.length)} $packages.");
     }
 
-    if (failures > 0) {
-      var packages = pluralize("package", failures);
-      log.message("Failed to reinstall ${log.red(failures)} $packages.");
+    if (failures.length > 0) {
+      var packages = pluralize("package", failures.length);
+      var buffer = new StringBuffer(
+          "Failed to reinstall ${log.red(failures.length)} $packages:\n");
+
+      for (var id in failures) {
+        buffer.write("- ${log.bold(id.name)} ${id.version}");
+        if (cache.sources[id.source] != cache.sources.defaultSource) {
+          buffer.write(" from ${id.source}");
+        }
+        buffer.writeln();
+      }
+
+      log.message(buffer.toString());
     }
 
     var results = await globals.repairActivatedPackages();
-    if (results.first > 0) {
-      var packages = pluralize("package", results.first);
-      log.message("Reactivated ${log.green(results.first)} $packages.");
+    if (results.first.length > 0) {
+      var packages = pluralize("package", results.first.length);
+      log.message("Reactivated ${log.green(results.first.length)} $packages.");
     }
 
-    if (results.last > 0) {
-      var packages = pluralize("package", results.last);
-      log.message("Failed to reactivate ${log.red(results.last)} $packages.");
+    if (results.last.length > 0) {
+      var packages = pluralize("package", results.last.length);
+      log.message(
+          "Failed to reactivate ${log.red(results.last.length)} $packages:\n" +
+          results.last.map((name) => "- ${log.bold(name)}").join("\n"));
     }
 
-    if (successes == 0 && failures == 0) {
+    if (successes.length == 0 && failures.length == 0) {
       log.message("No packages in cache, so nothing to repair.");
     }
 
-    if (failures > 0) await flushThenExit(exit_codes.UNAVAILABLE);
+    if (failures.length > 0 || results.last.length > 0) {
+      await flushThenExit(exit_codes.UNAVAILABLE);
+    }
   }
 }