@@ -1,19 +1,34 @@
 var generateJson = require("./scripts/generateJson");
 var generateNativeCode = require("./scripts/generateNativeCode");
 var generateMissingTests = require("./scripts/generateMissingTests");
+var submoduleStatus = require("../lifecycleScripts/submodules/getStatus");
 
 module.exports = function generate() {
-  return new Promise(function(resolve, reject) {
-    try {
+  return submoduleStatus()
+    .then(function(statuses) {
+      var dirtySubmodules = statuses
+        .filter(function(status) {
+          return status.onNewCommit
+            || status.needsInitialization
+            || status.workDirDirty;
+        });
+
+      if (dirtySubmodules.length) {
+        console.log("WARNING - Some submodules are out-of-sync");
+        dirtySubmodules.forEach(function(submodule) {
+          console.log("\t" + submodule.name);
+        });
+      }
+    })
+    .then(function() {
       generateJson();
       generateNativeCode();
       generateMissingTests();
-      resolve();
-    }
-    catch(e) {
-      reject(e);
-    }
-  });
+    })
+    .catch(function(e) {
+      console.log("ERROR - Could not generate native code");
+      console.log(e);
+    });
 }
 
 if (require.main === module) {
 
@@ -121,7 +121,6 @@ function build() {
     return arg;
   });
 
-  console.log(args);
   return new Promise(function(resolve, reject) {
     var child = cp.spawn(cmd, args, opts);
     child.on("close", function(code) {
 
@@ -3,11 +3,11 @@ var path = require("path");
 
 var local = path.join.bind(path, __dirname);
 
+var submodules = require(local("submodules"));
 var configure = require(local("configureLibssh2"));
 var generate = require(local("../generate"));
 
 module.exports = function prepareForBuild() {
-
   return new Promise(function(resolve, reject) {
     cp.exec("npm install --ignore-scripts", function(err, stdout, stderr) {
       if (err) {
@@ -19,7 +19,11 @@ module.exports = function prepareForBuild() {
         console.info(stdout);
       }
     });
-  }).then(function() {
+  })
+  .then(function() {
+    return submodules();
+  })
+  .then(function() {
     return Promise.all([
       configure(),
       generate()
 
@@ -0,0 +1,37 @@
+var path = require("path");
+var rootDir = path.join(__dirname, "../..");
+var exec = require(path.join(rootDir, "./utils/execPromise"));
+
+module.exports = function getStatus() {
+  return exec("git submodule status", { cwd: rootDir})
+    .then(function(stdout) {
+      function getStatusPromiseFromLine(line) {
+        var lineSections = line.trim().split(" ");
+        var onNewCommit = !!~lineSections[0].indexOf("+");
+        var needsInitialization = !!~lineSections[0].indexOf("-");
+        var commitOid = lineSections[0].replace("+", "").replace("-", "");
+        var name = lineSections[1];
+
+        return exec("git status", { cwd: path.join(rootDir, name)})
+          .then(function(workDirStatus) {
+            return {
+              commitOid: commitOid,
+              onNewCommit: onNewCommit,
+              name: name,
+              needsInitialization: needsInitialization,
+              workDirDirty: !~workDirStatus
+                .trim()
+                .split("\n")
+                .pop()
+                .indexOf("nothing to commit")
+            };
+          });
+      }
+
+      return Promise.all(stdout
+        .trim()
+        .split("\n")
+        .map(getStatusPromiseFromLine)
+      );
+    });
+};
@@ -0,0 +1,74 @@
+var path = require("path");
+var rootDir = path.join(__dirname, "../..");
+
+var gitExecutableLocation = require(
+  path.join(rootDir, "./utils/gitExecutableLocation")
+);
+var submoduleStatus = require("./getStatus");
+
+var exec = require(path.join(rootDir, "./utils/execPromise"));
+
+module.exports = function submodules() {
+  return gitExecutableLocation()
+    .catch(function() {
+      console.log("ERROR - Compilation of NodeGit requires git CLI to be " +
+        "installed and on the path");
+
+      throw new Error("git CLI is not installed or not on the path");
+    })
+    .then(function() {
+      return submoduleStatus();
+    })
+    .then(function(statuses) {
+      function printSubmodule(submoduleName) {
+        console.log("\t" + submoduleName);
+      }
+
+      var dirtySubmodules = statuses
+      .filter(function(status) {
+        return status.workDirDirty && !status.needsInitialization;
+      })
+      .map(function(dirtySubmodule) {
+        return dirtySubmodule.name;
+      });
+
+      if (dirtySubmodules.length) {
+        console.log(
+          "ERROR - The following submodules have uncommited changes:"
+        );
+        dirtySubmodules.forEach(printSubmodule);
+        console.log(
+          "\nThey must either be committed or discarded before we build"
+        );
+
+        throw new Error("Dirty Submodules: " + dirtySubmodules.join(" "));
+      }
+
+      var outOfSyncSubmodules = statuses
+        .filter(function(status) {
+          return status.onNewCommit && !status.needsInitialization;
+        })
+        .map(function(outOfSyncSubmodule) {
+          return outOfSyncSubmodule.name;
+        });
+
+      if (outOfSyncSubmodules.length) {
+        console.log(
+          "WARNING - The following submodules are pointing to an new commit:"
+        );
+        outOfSyncSubmodules.forEach(printSubmodule);
+        console.log("\nThey will not be updated.");
+      }
+
+      return Promise.all(statuses
+        .filter(function(status) {
+          return !status.onNewCommit;
+        })
+        .map(function(submoduleToUpdate) {
+          return exec(
+            "git submodule update --init --recursive " + submoduleToUpdate.name
+          );
+        })
+      );
+    });
+};
@@ -0,0 +1,23 @@
+var cp = require("child_process");
+
+module.exports = function gitExecutableLocation() {
+  return new Promise(function(resolve, reject) {
+    var cmd;
+
+    if (process.platform === "win32") {
+      cmd = "where git";
+    }
+    else {
+      cmd = "which git";
+    }
+
+    cp.exec(cmd, function(err, stdout, stderr) {
+      if (err) {
+        reject(err, stderr);
+      }
+      else {
+        resolve(stdout);
+      }
+    });
+  });
+};