From c4c3ab9a49d824eb64dbf3d1e1c6c079ffff92cb Mon Sep 17 00:00:00 2001
From: Karen Arutyunov <karen@codesynthesis.com>
Date: Thu, 27 Jul 2023 21:49:44 +0300
Subject: Fix inability to fetch repository containing toolchain-unsatisfied
 packages (GH issue #305)

Note: the breaking commit is d6d72bc6e454.
---
 bpkg/rep-fetch.cxx | 23 ++++++++++++++---------
 1 file changed, 14 insertions(+), 9 deletions(-)

(limited to 'bpkg/rep-fetch.cxx')

diff --git a/bpkg/rep-fetch.cxx b/bpkg/rep-fetch.cxx
index 6f31478..d7f4cc6 100644
--- a/bpkg/rep-fetch.cxx
+++ b/bpkg/rep-fetch.cxx
@@ -314,7 +314,10 @@ namespace bpkg
           if (bs                  &&
               r.build2_dependency &&
               !satisfy_build2 (co, *r.build2_dependency))
+          {
             bs = false;
+            pds.clear (); // Won't now be used.
+          }
 
           nvs.push_back (move (r));
         }
@@ -328,7 +331,9 @@ namespace bpkg
         }
 
         mfs.push_back (move (f));
-        pds.push_back (move (d));
+
+        if (bs)
+          pds.push_back (move (d));
       }
 
       // Note that for the directory-based repositories we also query
@@ -1110,12 +1115,6 @@ namespace bpkg
       //
       if (rl.directory_based ())
       {
-        // Wouldn't be here otherwise. Note that rep_fetch_data is retrieved
-        // by rep_fetch() with false passed as the ignore_toolchain argument
-        // (see rep_fetch() for more details).
-        //
-        assert (!pis.empty ());
-
         // Note that we can't check if the external package of this upstream
         // version and revision is already available in the configuration
         // until we fetch all the repositories, as some of the available
@@ -1129,7 +1128,7 @@ namespace bpkg
             path_cast<dir_path> (rl.path () / *pm.location),
             pm.name,
             pm.version,
-            &pis[i],
+            !pis.empty () ? &pis[i] : nullptr,
             false   /* check_external */));
 
         if (v)
@@ -1314,6 +1313,12 @@ namespace bpkg
     // repository fragments list, as well as its prerequisite and complement
     // repository sets.
     //
+    // Note that we do this in the forward compatible manner ignoring
+    // unrecognized manifest values and unsatisfied build2 toolchain
+    // constraints in the package manifests. This approach allows older
+    // toolchains to work with newer repositories, successfully building the
+    // toolchain-satisfied packages and only failing for unsatisfied ones.
+    //
     rep_fetch_data rfd (
       rep_fetch (co,
                  &db.config_orig,
@@ -1321,7 +1326,7 @@ namespace bpkg
                  rl,
                  dependent_trust,
                  true /* ignore_unknow */,
-                 false /* ignore_toolchain */,
+                 true /* ignore_toolchain */,
                  false /* expand_values */,
                  true /* load_buildfiles */));
 
-- 
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