Explain EUSER better for paludis -i foo::/

3 files changed, 27 insertions, 0 deletions

diff --git a/doc/faq/index.html.part b/doc/faq/index.html.part
index ab270d7fc..2b43a0928 100644
--- a/doc/faq/index.html.part
+++ b/doc/faq/index.html.part
@@ -44,6 +44,8 @@ functionality. Pestering anyone about these is liable to get you hurt a lot.</p>
     <li><a href="operation.html#info">Get package information for a bug report</a></li>
     <li><a href="operation.html#arrows">What do those fancy arrows when merging things mean?</a></li>
     <li><a href="operation.html#updates">Profiles Updates for Package Moves and Slot Moves</a></li>
+    <li><a href="operation.html#repospecs">I can't install <code>*/*::installed</code> or
+        <code>*/*::overlay-&gt;</code></a></li>
 </ul>
 
 <h2>Stricter than Portage</h2>
diff --git a/doc/faq/operation.html.part b/doc/faq/operation.html.part
index b408f6ff8..7cd60893f 100644
--- a/doc/faq/operation.html.part
+++ b/doc/faq/operation.html.part
@@ -8,6 +8,8 @@
     <li><a href="operation.html#info">Get package information for a bug report</a></li>
     <li><a href="operation.html#arrows">What do those fancy arrows when merging things mean?</a></li>
     <li><a href="operation.html#updates">Profiles Updates for Package Moves and Slot Moves</a></li>
+    <li><a href="operation.html#repospecs">I can't install <code>*/*::installed</code> or
+        <code>*/*::overlay-&gt;</code></a></li>
 </ul>
 
 <h2 id="updatingdepends">Paludis does not update DEPENDs of already installed packages</h2>
@@ -99,3 +101,9 @@ variable to <code>yes</code> and then sync to perform updates.</p>
 the update. In this situation, you should generally manually uninstall the older of <code>foo</code> or
 <code>bar</code>.</p>
 
+<h2 id="repospecs">I can't install <code>*/*::installed</code> or <code>*/*::overlay-&gt;</code></h2>
+
+<p>You can't install (or reinstall) a package ID that is already installed. The <code>foo/bar-1.23</code> you have
+installed has absolutely nothing whatsoever to do with any other <code>foo/bar-1.23</code>, and by specifying
+<code>::installed</code> or <code>::overlay-&gt;</code> you are specifically saying "give me the installed ID".</p>
+
diff --git a/paludis/install_task.cc b/paludis/install_task.cc
index 5d372ff36..95435c23b 100644
--- a/paludis/install_task.cc
+++ b/paludis/install_task.cc
@@ -468,6 +468,23 @@ InstallTask::_add_target(const std::string & target)
                         _imp->env, UserPackageDepSpecOptions() + updso_throw_if_set + updso_allow_wildcards,
                         filter::SupportsAction<InstallAction>())));
 
+        bool spec_is_installed(false);
+
+        if (spec->in_repository_ptr() &&
+                _imp->env->package_database()->has_repository_named(*spec->in_repository_ptr()) &&
+                _imp->env->package_database()->fetch_repository(*spec->in_repository_ptr())->installed_root_key())
+            spec_is_installed = true;
+        else if (spec->from_repository_ptr())
+            spec_is_installed = true;
+        else if (spec->installed_at_path_ptr())
+            spec_is_installed = true;
+
+        if (spec_is_installed)
+            Log::get_instance()->message("install_task.installed_spec", ll_warning, lc_context)
+                << "Target '" << target << "' appears to make use of ::repository restrictions "
+                << "that restrict to an installed repository. This probably does not do what you "
+                << "think it does. Consult the FAQ for an explanation";
+
         if (_imp->had_set_targets)
             throw HadBothPackageAndSetTargets();
         _imp->had_package_targets = true;