Don't drop empty objects/arrays in env params

There is a case where empty parameter values could get dropped
from environment parameters

In

```
{
    components: {
        component: {
            values: {}
        }
    }
}
```

component.values would be dropped because it contained an
empty object.
Signed-off-by: bryanl <bryanliles@gmail.com>

pkg/params/rice-box.go

@@ -25,19 +25,19 @@ func init() {
 	// define files
 	file2 := &embedded.EmbeddedFile{
 		Filename:    "modularize_params.libsonnet",
-		FileModTime: time.Unix(1530453707, 0),
+		FileModTime: time.Unix(1530832602, 0),
 		Content:     string("function(moduleName, params)\n    local prefix = if (moduleName == \"/\" || moduleName == \"\") then \"\" else \"%s.\" % moduleName;\n\n    local baseObject = if std.objectHas(params, \"global\")\n        then {global: params.global}\n        else {};\n\n    baseObject + {\n        components: {\n            [\"%s%s\" % [prefix, key]]: params.components[key]\n            for key in std.objectFieldsAll(params.components)\n        },\n    }"),
 	}
 	file3 := &embedded.EmbeddedFile{
 		Filename:    "params_for_module.libsonnet",
-		FileModTime: time.Unix(1530407391, 0),
-		Content:     string("function(moduleName, input)\n   local isModule(key) = std.length(std.split(key, \".\")) > 1;\n\n   local localizeKey(key) =\n      if isModule(key)\n      then\n         local parts = std.split(key, \".\");\n         parts[std.length(parts)-1]\n      else key;\n\n   local findInRoot(key, value) =\n      if isModule(key)\n      then {[key]:null}\n      else {[key]:value};\n\n   local findInModule(moduleName, key, value) =\n      if std.startsWith(key, moduleName)\n      then {[localizeKey(key)]: value}\n      else {[localizeKey(key)]: null};\n\n   local findValue(moduleName, key, value) =\n      if moduleName == \"/\"\n      then findInRoot(key, value)\n      else findInModule(moduleName, key, value);\n\n   local fn(moduleName, params) = [\n         findValue(moduleName, key, params.components[key])\n         for key in std.objectFields(params.components)\n   ];\n\n   {\n      local mash(ag, obj) = ag + obj,\n      components+: std.foldl(mash, std.prune(fn(moduleName, input)), {})\n   }\n"),
+		FileModTime: time.Unix(1530891505, 0),
+		Content:     string("function(moduleName, input)\n   local isModule(key) = std.length(std.split(key, \".\")) > 1;\n\n   local localizeKey(key) =\n      if isModule(key)\n      then\n         local parts = std.split(key, \".\");\n         parts[std.length(parts)-1]\n      else key;\n\n   local findInRoot(key, value) =\n      if isModule(key)\n      then {[key]:null}\n      else {[key]:value};\n\n   local findInModule(moduleName, key, value) =\n      if std.startsWith(key, moduleName)\n      then {[localizeKey(key)]: value}\n      else {[localizeKey(key)]: null};\n\n   local findValue(moduleName, key, value) =\n      if moduleName == \"/\"\n      then findInRoot(key, value)\n      else findInModule(moduleName, key, value);\n\n   local fn(moduleName, params) = [\n      findValue(moduleName, key, params.components[key])\n      for key in std.objectFields(params.components)\n   ];\n\n   local foldFn(aggregate, object) =\n      local o = {\n         components+: {\n            [x]:+ object[x]\n            for x in std.objectFields(object)\n            if object[x] != null\n         },\n      };\n\n      aggregate + o;\n\n   local a = fn(moduleName, input);\n\n   std.foldl(foldFn, a, {})\n\n"),
 	}
 
 	// define dirs
 	dir1 := &embedded.EmbeddedDir{
 		Filename:   "",
-		DirModTime: time.Unix(1530366356, 0),
+		DirModTime: time.Unix(1530832602, 0),
 		ChildFiles: []*embedded.EmbeddedFile{
 			file2, // "modularize_params.libsonnet"
 			file3, // "params_for_module.libsonnet"
@@ -51,7 +51,7 @@ func init() {
 	// register embeddedBox
 	embedded.RegisterEmbeddedBox(`scripts`, &embedded.EmbeddedBox{
 		Name: `scripts`,
-		Time: time.Unix(1530366356, 0),
+		Time: time.Unix(1530832602, 0),
 		Dirs: map[string]*embedded.EmbeddedDir{
 			"": dir1,
 		},

pkg/params/scripts/params_for_module.libsonnet

@@ -24,11 +24,22 @@ function(moduleName, input)
       else findInModule(moduleName, key, value);
 
    local fn(moduleName, params) = [
-         findValue(moduleName, key, params.components[key])
-         for key in std.objectFields(params.components)
+      findValue(moduleName, key, params.components[key])
+      for key in std.objectFields(params.components)
    ];
 
-   {
-      local mash(ag, obj) = ag + obj,
-      components+: std.foldl(mash, std.prune(fn(moduleName, input)), {})
-   }
+   local foldFn(aggregate, object) =
+      local o = {
+         components+: {
+            [x]:+ object[x]
+            for x in std.objectFields(object)
+            if object[x] != null
+         },
+      };
+
+      aggregate + o;
+
+   local a = fn(moduleName, input);
+
+   std.foldl(foldFn, a, {})
+

pkg/params/testdata/build_env_params/input.jsonnet

@@ -4,6 +4,7 @@ local envParams = params + {
     "app.project-1.deployment": {
       type: "nested",
       replicas: 1,
+      values: {},
     },
     "deployment": {
       type: "root",

pkg/params/testdata/build_env_params/module.jsonnet

@@ -2,7 +2,8 @@
    "components": {
       "deployment": {
          "replicas": 1,
-         "type": "nested"
+         "type": "nested",
+         "values": { }
       }
    }
 }