Don't recompile dependency executables that haven't changed.

sdk/lib/_internal/pub/lib/src/solver/solve_report.dart

Index: sdk/lib/_internal/pub/lib/src/solver/solve_report.dart
diff --git a/sdk/lib/_internal/pub/lib/src/solver/solve_report.dart b/sdk/lib/_internal/pub/lib/src/solver/solve_report.dart
index 7fed60a7ea60453232abd95ae06997f136837b53..76278a29dae127012155b46ea38e324b2b4d5a44 100644
--- a/sdk/lib/_internal/pub/lib/src/solver/solve_report.dart
+++ b/sdk/lib/_internal/pub/lib/src/solver/solve_report.dart
@@ -63,8 +63,7 @@ class SolveReport {
       if (newId == null) return true;
 
       // The dependency existed before, so see if it was modified.
-      return !_descriptionsEqual(oldId, newId) ||
-          oldId.version != newId.version;
+      return !_sources.idsEqual(oldId, newId);
     }).length;
 
     if (dryRun) {
@@ -169,7 +168,7 @@ class SolveReport {
     } else if (oldId == null) {
       icon = log.green("+ ");
       addedOrRemoved = true;
-    } else if (!_descriptionsEqual(oldId, newId)) {
+    } else if (!_sources.idDescriptionsEqual(oldId, newId)) {
       icon = log.cyan("* ");
       changed = true;
     } else if (oldId.version < newId.version) {
@@ -236,13 +235,6 @@ class SolveReport {
     _output.writeln();
   }
 
-  /// Returns `true` if [a] and [b] are from the same source and have the same
-  /// description.
-  bool _descriptionsEqual(PackageId a, PackageId b) {
-    if (a.source != b.source) return false;
-    return _sources[a.source].descriptionsEqual(a.description, b.description);
-  }
-
   /// Writes a terse description of [id] (not including its name) to the output.
   void _writeId(PackageId id) {
     _output.write(id.version);