From 2903ad8d65a76e9ae6da9a8c4ac13591aeb879d8 Mon Sep 17 00:00:00 2001
From: Karen Arutyunov <karen@codesynthesis.com>
Date: Mon, 30 Jan 2023 16:45:00 +0300
Subject: Fix resulting names ordering for system_package_names()

---
 bpkg/system-package-manager.cxx             | 44 +++++++++++++++++++++++------
 bpkg/system-package-manager.test.testscript |  3 +-
 2 files changed, 36 insertions(+), 11 deletions(-)

diff --git a/bpkg/system-package-manager.cxx b/bpkg/system-package-manager.cxx
index 3585ba3..b5fa333 100644
--- a/bpkg/system-package-manager.cxx
+++ b/bpkg/system-package-manager.cxx
@@ -197,27 +197,53 @@ namespace bpkg
     auto name_values = [&aps] (const string& n, const semantic_version& v)
     {
       strings r;
+
+      // For each available package sort the system package names in the
+      // distribution version descending order and then append them to the
+      // resulting list, keeping this order and suppressing duplicates.
+      //
+      using name_version = pair<string, semantic_version>;
+      vector<name_version> nvs; // Reuse the buffer.
+
       for (const auto& a: aps)
       {
+        nvs.clear ();
+
         const shared_ptr<available_package>& ap (a.first);
 
-        for (const distribution_name_value& nv: ap->distribution_values)
+        for (const distribution_name_value& dv: ap->distribution_values)
         {
-          if (optional<string> d = nv.distribution ("-name"))
+          if (optional<string> d = dv.distribution ("-name"))
           {
             pair<string, semantic_version> dnv (
-              parse_distribution (move (*d), nv.name, ap, a.second));
+              parse_distribution (move (*d), dv.name, ap, a.second));
 
-            if (dnv.first  == n &&
-                dnv.second <= v &&
-                find_if (r.begin (), r.end (),
-                         [&nv] (const string& v) {return nv.value == v;}) ==
-                r.end ())
+            if (dnv.first == n && dnv.second <= v)
             {
-              r.push_back (nv.value);
+              // Add the name/version pair to the sorted vector.
+              //
+              name_version nv (make_pair (dv.value, move (dnv.second)));
+
+              nvs.insert (upper_bound (nvs.begin (), nvs.end (), nv,
+                                       [] (const name_version& x,
+                                           const name_version& y)
+                                       {return x.second > y.second;}),
+                          move (nv));
             }
           }
         }
+
+        // Append the sorted names to the resulting list.
+        //
+        for (name_version& nv: nvs)
+        {
+          if (find_if (r.begin (), r.end (),
+                       [&nv] (const string& n) {return nv.first == n;}) ==
+              r.end ())
+          {
+            r.push_back (move (nv.first));
+          }
+        }
       }
 
       return r;
diff --git a/bpkg/system-package-manager.test.testscript b/bpkg/system-package-manager.test.testscript
index b993793..dc672f5 100644
--- a/bpkg/system-package-manager.test.testscript
+++ b/bpkg/system-package-manager.test.testscript
@@ -26,14 +26,13 @@
     summary: curl
     license: curl
     EOI
-#\
+
   $* debian 10 -- libcurl libcurl7.64.manifest libcurl7.84.manifest >>EOO;
     libcurl4 libcurl4-openssl-dev
     libcurl3-gnutls libcurl4-gnutls-dev
     libcurl2 libcurl2-dev libcurl2-doc
     libcurl2 libcurl2-dev
     EOO
-#\
   $* debian 9 -- libcurl libcurl7.64.manifest libcurl7.84.manifest >>EOO;
     libcurl2 libcurl2-dev libcurl2-doc
     libcurl2 libcurl2-dev
-- 
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