Remove arraysets if arrays present

Summary:
# What?
Remove `arraysets` if `arrays` present.

# Why?
This combination can lead to runtime failures.

# Fixtures
Generated fixtures must not change.

# Context
`arraysets`, `no_use_hack_collections`, `stricttypes`, `array_migration`, `shape_arraykeys`, `const_collections` are all compiler options that control the generation of container fields. To make code generator simpler and easier to reason about, identify which of these can be removed/merged.

The new options based on the ones that are currently in use:

`legacy_arrays_` replaces `no_use_hack_collections_`.
`hack_collections_`, which was the implicit default in the absence of `arrays_` and `no_use_hack_collections_`, is now explicit.
`arrays_` will eventually become the default and cease to exist as an explicit option.

# The steps
The item in bold corresponds to the current diff.
1. Use new compiler options based on the ones that already exist.
1. Make arrays the default option.
1. Use the legacy arrays + hack collections logical equivalent of arrays.
1. Introduce hack collections wherever necessary.
1. Replace no use hack collections with legacy arrays.
1. **Remove arraysets if arrays present.**
1. Rename `no_use_hack_collections` compiler option to `legacy_arrays`.
1. Add `hack_collections` compiler option.
1. Remove references to the `ARRAYS` compiler option.
1. Delete the `arrays` compiler option.

Reviewed By: rmakheja

Differential Revision: D67573143

fbshipit-source-id: cad66b814fdd3f81c2862ce11d41cc0d0d07310a

third-party/thrift/src/thrift/compiler/generate/t_hack_generator.cc

@@ -157,6 +157,9 @@ class t_hack_generator : public t_concat_generator {
     } else if (no_use_hack_collections_ && arrays_) {
       throw std::runtime_error(
           "Don't use no_use_hack_collections with arrays. Just use arrays");
+    } else if (arraysets_ && !(legacy_arrays_ || hack_collections_)) {
+      throw std::runtime_error(
+          "Don't use arraysets without either legacy_arrays or hack_collections");
     } else if (mangled_services_ && has_hack_namespace) {
       throw std::runtime_error(
           "Don't use mangledsvcs with hack namespaces or package.");
@@ -1386,7 +1389,7 @@ void t_hack_generator::generate_json_container(
       indent(out) << container << " = vec[];\n";
     }
   } else if (ttype->is_set()) {
-    if (arraysets_ && (legacy_arrays_ || hack_collections_)) {
+    if (arraysets_) {
       indent(out) << container << " = dict[];\n";
     } else if (hack_collections_) {
       indent(out) << container << " = Set {};\n";
@@ -1435,7 +1438,7 @@ void t_hack_generator::generate_json_set_element(
   t_field felem(tset->get_elem_type(), elem);
   indent(out) << declare_field(&felem, true, true, true).substr(1) << "\n";
   generate_json_field(out, namer, &felem, "", "", value);
-  if (arraysets_ && (legacy_arrays_ || hack_collections_)) {
+  if (arraysets_) {
     indent(out) << prefix_thrift << "[" << elem << "] = true;\n";
   } else if (hack_collections_) {
     indent(out) << prefix_thrift << "->add(" << elem << ");\n";
@@ -2304,7 +2307,7 @@ std::string t_hack_generator::render_default_value(const t_type* type) {
       dval = "vec[]";
     }
   } else if (type->is_set()) {
-    if (arraysets_ && (legacy_arrays_ || hack_collections_)) {
+    if (arraysets_) {
       dval = "dict[]";
     } else if (hack_collections_) {
       dval = "Set {}";
@@ -3034,7 +3037,7 @@ void t_hack_generator::generate_php_type_spec(
     }
     indent(out) << "'etype' => " << type_to_enum(etype) << ",\n";
     generate_php_type_spec_shape_elt_helper(out, "elem", etype, depth);
-    if (arraysets_ && (hack_collections_ || legacy_arrays_)) {
+    if (arraysets_) {
       indent(out) << "'format' => 'array',\n";
     } else if (hack_collections_) {
       indent(out) << "'format' => 'collection',\n";
@@ -6684,14 +6687,7 @@ std::string t_hack_generator::type_to_typehint(
   } else if (const auto* tset = dynamic_cast<const t_set*>(ttype)) {
     std::string prefix;
     std::string suffix = ">";
-    // The order of the ifs matters in the code below.
-    // Even though there is a small amount of duplicated code below,
-    // any alternative approaches to achieve the same outcome seem
-    // make it harder to see the order clearly.
-    if (arraysets_) {
-      prefix = "dict";
-      suffix = ", bool>";
-    } else if (!legacy_arrays_ && !hack_collections_) {
+    if (!legacy_arrays_ && !hack_collections_) {
       prefix = "keyset";
     } else if (arraysets_ || variations[TypeToTypehintVariations::IS_SHAPE]) {
       prefix = "dict";
@@ -7440,7 +7436,7 @@ std::string t_hack_generator::declare_field(
         result += " = vec[]";
       }
     } else if (type->is_set()) {
-      if (arraysets_ && (legacy_arrays_ || hack_collections_)) {
+      if (arraysets_) {
         result += " = dict[]";
       } else if (hack_collections_) {
         result += " = Set {}";

third-party/thrift/src/thrift/compiler/test/fixtures/shape_hack_arrays/cmd

@@ -1,2 +1 @@
 hack: hack:shapes=1,shapes_allow_unknown_fields=1,arrays=1,shapes_use_pipe_structure=1 src/module.thrift
-hack_array_sets: hack:shapes=1,shapes_allow_unknown_fields=1,arrays=1,shapes_use_pipe_structure=1,arraysets=1 src/module.thrift