Fix alias completion and overwritting

src/alias_registry.cc

@@ -1,6 +1,7 @@
 #include "alias_registry.hh"
 
 #include "command_manager.hh"
+#include "containers.hh"
 
 namespace Kakoune
 {
@@ -9,7 +10,11 @@ void AliasRegistry::add_alias(String alias, String command)
 {
     kak_assert(not alias.empty());
     kak_assert(CommandManager::instance().command_defined(command));
-    m_aliases.append({std::move(alias), std::move(command) });
+    auto it = m_aliases.find(alias);
+    if (it == m_aliases.end())
+        m_aliases.append({std::move(alias), std::move(command) });
+    else
+        it->value = std::move(command);
 }
 
 void AliasRegistry::remove_alias(StringView alias)
@@ -45,4 +50,17 @@ Vector<StringView> AliasRegistry::aliases_for(StringView command) const
     return res;
 }
 
+Vector<std::pair<StringView, StringView>> AliasRegistry::flatten_aliases() const
+{
+    Vector<std::pair<StringView, StringView>> res;
+    if (m_parent)
+        res = m_parent->flatten_aliases();
+    for (auto& alias : m_aliases)
+    {
+        if (not contains(transformed(res, [](const std::pair<StringView, StringView>& val) { return val.first; }), alias.key))
+            res.emplace_back(alias.key, alias.value);
+    }
+    return res;
+}
+
 }

src/alias_registry.hh

@@ -18,10 +18,9 @@ public:
 
     using AliasMap = IdMap<String, MemoryDomain::Aliases>;
     using iterator = AliasMap::const_iterator;
-    iterator begin() const { return m_aliases.begin(); }
-    iterator end() const { return m_aliases.end(); }
 
     Vector<StringView> aliases_for(StringView command) const;
+    Vector<std::pair<StringView, StringView>> flatten_aliases() const;
 
 private:
     friend class Scope;

src/command_manager.cc

@@ -571,10 +571,10 @@ Completions CommandManager::complete(const Context& context,
             if (prefix_match(command.first, prefix))
                 result.candidates.push_back(command.first);
         }
-        for (auto& alias : context.aliases())
+        for (auto& alias : context.aliases().flatten_aliases())
         {
-            if (prefix_match(alias.key, prefix))
-                result.candidates.push_back(alias.key);
+            if (prefix_match(alias.first, prefix))
+                result.candidates.push_back(alias.first.str());
         }
         std::sort(result.candidates.begin(), result.candidates.end());
         return result;