From 40d5d918baf19b565da0352f3e97afde37064009 Mon Sep 17 00:00:00 2001
From: James Turner <zakalawe@mac.com>
Date: Thu, 30 Aug 2018 15:23:45 +0100
Subject: [PATCH] Allow local acft to override packaged acft
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When an explicit aircraft-dir is set, check this location before
checking installed packages. This allows setting —aircraft and
-aircraft-dir to correctly take precedence over a package.
---
 src/Main/fg_init.cxx | 30 +++++++++++++++++++++++++++---
 1 file changed, 27 insertions(+), 3 deletions(-)

diff --git a/src/Main/fg_init.cxx b/src/Main/fg_init.cxx
index 45352ed7f..a3bb328e2 100644
--- a/src/Main/fg_init.cxx
+++ b/src/Main/fg_init.cxx
@@ -193,6 +193,24 @@ public:
     _cache = autoSave->getNode("sim/startup/path-cache", true);
   }
   
+  /**
+   * @brief haveExplicitAircraft - check if the combination of /sim/aircraft
+   * and /sim/aircraft-dir defines an explicit -set.xml. We need to detect
+   * this case to short-circuit package detection
+   * @return
+   */
+  bool haveExplicitAircraft() const
+  {
+      const std::string aircraftDir = fgGetString("/sim/aircraft-dir", "");
+      if (aircraftDir.empty()) {
+          return false;
+      }
+
+      const std::string aircraft = fgGetString( "/sim/aircraft", "");
+      SGPath setFile = SGPath::fromUtf8(aircraftDir) / (aircraft + "-set.xml");
+      return setFile.exists();
+  }
+
   bool loadAircraft()
   {
     std::string aircraft = fgGetString( "/sim/aircraft", "");
@@ -624,11 +642,18 @@ int fgInitAircraft(bool reinit)
         flightgear::Options::sharedInstance()->initAircraft();
     }
     
+    FindAndCacheAircraft f(globals->get_props());
+    const bool haveExplicit = f.haveExplicitAircraft();
+
     SGSharedPtr<Root> pkgRoot(globals->packageRoot());
     SGPropertyNode* aircraftProp = fgGetNode("/sim/aircraft", true);
-
     string aircraftId(aircraftProp->getStringValue());
-    PackageRef acftPackage = pkgRoot->getPackageById(aircraftId);
+
+    PackageRef acftPackage;
+    if (!haveExplicit) {
+        acftPackage = pkgRoot->getPackageById(aircraftId);
+    }
+
     if (acftPackage) {
         if (acftPackage->isInstalled()) {
             SG_LOG(SG_GENERAL, SG_INFO, "Loading aircraft from package:" << acftPackage->qualifiedId());
@@ -667,7 +692,6 @@ int fgInitAircraft(bool reinit)
 
     initAircraftDirsNasalSecurity();
 
-    FindAndCacheAircraft f(globals->get_props());
     if (!f.loadAircraft()) {
         return flightgear::FG_OPTIONS_ERROR;
     }