1 files changed, 27 insertions, 2 deletions

diff --git a/src/nix/flake.cc b/src/nix/flake.cc
index 6f6d3c130..6f6d1a0aa 100644
--- a/src/nix/flake.cc
+++ b/src/nix/flake.cc
@@ -7,6 +7,7 @@
 #include "flake/flake.hh"
 #include "get-drvs.hh"
 #include "store-api.hh"
+#include "derivations.hh"
 
 #include <nlohmann/json.hpp>
 #include <queue>
@@ -301,13 +302,27 @@ struct CmdFlakeCheck : FlakeCommand, MixJSON
                 // FIXME: check meta attributes
                 return drvInfo->queryDrvPath();
             } catch (Error & e) {
-                e.addPrefix(fmt("while checking flake output attribute '" ANSI_BOLD "%s" ANSI_NORMAL "':\n", attrPath));
+                e.addPrefix(fmt("while checking the derivation '" ANSI_BOLD "%s" ANSI_NORMAL "':\n", attrPath));
                 throw;
             }
         };
 
         PathSet drvPaths;
 
+        auto checkApp = [&](const std::string & attrPath, Value & v) {
+            try {
+                auto app = App(*state, v);
+                for (auto & i : app.context) {
+                    auto [drvPath, outputName] = decodeContext(i);
+                    if (!outputName.empty() && nix::isDerivation(drvPath))
+                        drvPaths.insert(drvPath + "!" + outputName);
+                }
+            } catch (Error & e) {
+                e.addPrefix(fmt("while checking the app definition '" ANSI_BOLD "%s" ANSI_NORMAL "':\n", attrPath));
+                throw;
+            }
+        };
+
         {
             Activity act(*logger, lvlInfo, actUnknown, "evaluating flake");
 
@@ -337,9 +352,19 @@ struct CmdFlakeCheck : FlakeCommand, MixJSON
                                     name + "." + (std::string) aCheck.name, *aCheck.value);
                         }
 
+                        else if (name == "apps") {
+                            state->forceAttrs(vProvide);
+                            for (auto & aCheck : *vProvide.attrs)
+                                checkApp(
+                                    name + "." + (std::string) aCheck.name, *aCheck.value);
+                        }
+
                         else if (name == "defaultPackage" || name == "devShell")
                             checkDerivation(name, vProvide);
 
+                        else if (name == "defaultApp")
+                            checkApp(name, vProvide);
+
                     } catch (Error & e) {
                         e.addPrefix(fmt("while checking flake output '" ANSI_BOLD "%s" ANSI_NORMAL "':\n", name));
                         throw;
@@ -347,7 +372,7 @@ struct CmdFlakeCheck : FlakeCommand, MixJSON
                 });
         }
 
-        if (build) {
+        if (build && !drvPaths.empty()) {
             Activity act(*logger, lvlInfo, actUnknown, "running flake checks");
             store->buildPaths(drvPaths);
         }