Add versioned Provides support

- Add a new dpkg --assert-versioned-provides command.
- Packages can provide a specific version, “virtual (= 1.0)” which will
  be honored, previously it would just be accepted when parsing.
- Non-versioned virtual packages will not satisfy versioned dependencies.
- Versioned virtual packages will satisfy non-versioned dependencies.

This commit is very slightly based on the code reverted in commit
7df7d53a57b9913f4a20b2c9dcd554a2d88ff9f3, which was mostly skeletal.

Closes: #7330, #24934, #112131, #134582, #180316

Based-on-patch-by: Ben Collins <bcollins@debian.org>

1 files changed, 10 insertions, 2 deletions

diff --git a/src/enquiry.c b/src/enquiry.c
index f1597b002..e3f49cfbb 100644
--- a/src/enquiry.c
+++ b/src/enquiry.c
@@ -432,6 +432,14 @@ assertmultiarch(const char *const *argv)
   return assert_version_support(argv, &version, _("multi-arch"));
 }
 
+int
+assertverprovides(const char *const *argv)
+{
+  struct dpkg_version version = { 0, "1.17.11", NULL };
+
+  return assert_version_support(argv, &version, _("versioned Provides"));
+}
+
 /**
  * Print a single package which:
  *  (a) is the target of one or more relevant predependencies.
@@ -508,13 +516,13 @@ predeppackage(const char *const *argv)
           pkg = trypkg;
           break;
         }
-        if (possi->verrel != DPKG_RELATION_NONE)
-          continue;
         for (provider = possi->ed->depended.available;
              !pkg && provider;
              provider = provider->next) {
           if (provider->up->type != dep_provides)
             continue;
+          if (!pkg_virtual_deppossi_satisfied(possi, provider))
+            continue;
           trypkg = provider->up->up;
           if (!trypkg->files)
             continue;