hg: remove extra semicolons in structs

Summary:
`PyObject_HEAD` is macro that ends with a semicolon when is is resolved. Thus `PyObject_HEAD;` ends in two semicolons.
Tolerating extra semicolons is a gcc feature, not a standard one.
I am adding the explanation for `// clang-format off` only once per file.

https://stackoverflow.com/questions/49529130/are-extra-semicolons-allowed-inside-struct-declarations?rq=1&utm_medium=organic&utm_source=google_rich_qa&utm_campaign=google_rich_qa

Differential Revision: D7568269

fbshipit-source-id: 5afcfd7d96dc638cd0673d25809c9c43d58d00de

hgext/extlib/cfastmanifest.c

@@ -16,16 +16,23 @@ typedef unsigned char bool;
 
 #include "hgext/extlib/cfastmanifest/tree.h"
 
+// clang-format off
+// clang thinks that PyObject_HEAD should be on the same line as the next line
+// since there is no semicolong after it. There is no semicolon because
+// PyObject_HEAD macro already contains one and MSVC does not support
+// extra semicolons.
 typedef struct {
-  PyObject_HEAD;
+  PyObject_HEAD
   tree_t *tree;
 } fastmanifest;
+// clang-format on
 
+// clang-format off
 typedef struct {
-  PyObject_HEAD;
+  PyObject_HEAD
   iterator_t *iterator;
 } fmIter;
-
+// clang-format on
 
 static PyTypeObject fastmanifestType;
 static PyTypeObject fastmanifestKeysIterator;

hgext/extlib/cstore/py-cdatapack.h

@@ -24,22 +24,30 @@ extern "C" {
 
 // ====  py_cdatapack PyObject declaration ====
 
+// clang-format off
+// clang thinks that PyObject_HEAD should be on the same line as the next line
+// since there is no semicolong after it. There is no semicolon because
+// PyObject_HEAD macro already contains one and MSVC does not support
+// extra semicolons.
 struct py_cdatapack {
-  PyObject_HEAD;
+  PyObject_HEAD
 
   bool initialized;
   datapack_handle_t *handle;
 };
+// clang-format on
 
 // ====  py_cdatapack_iterator PyObject declaration ====
 
+// clang-format off
 typedef struct {
-  PyObject_HEAD;
+  PyObject_HEAD
 
   py_cdatapack *datapack;
   const uint8_t *ptr;
   const uint8_t *end;
 } py_cdatapack_iterator;
+// clang-format on
 
 // ====  cdatapack_deltas_iterator class methods ====
 

hgext/extlib/cstore/py-structs.h

@@ -17,14 +17,21 @@
 #include "hgext/extlib/cstore/pythonutil.h"
 #include "hgext/extlib/cstore/uniondatapackstore.h"
 
+// clang-format off
+// clang thinks that PyObject_HEAD should be on the same line as the next line
+// since there is no semicolong after it. There is no semicolon because
+// PyObject_HEAD macro already contains one and MSVC does not support
+// extra semicolons.
 struct py_datapackstore {
-  PyObject_HEAD;
+  PyObject_HEAD
 
   DatapackStore datapackstore;
 };
+// clang-format on
 
+// clang-format off
 struct py_uniondatapackstore {
-  PyObject_HEAD;
+  PyObject_HEAD
 
   std::shared_ptr<UnionDatapackStore> uniondatapackstore;
 
@@ -32,5 +39,6 @@ struct py_uniondatapackstore {
   std::vector<PythonObj> cstores;
   std::vector<std::shared_ptr<PythonDataStore>> pystores;
 };
+// clang-format on
 
 #endif // FBHGEXT_CSTORE_PY_STRUCTS_H

hgext/extlib/cstore/py-treemanifest.h

@@ -27,19 +27,27 @@
 #define FILENAME_BUFFER_SIZE 16348
 #define FLAG_SIZE 1
 
+// clang-format off
+// clang thinks that PyObject_HEAD should be on the same line as the next line
+// since there is no semicolong after it. There is no semicolon because
+// PyObject_HEAD macro already contains one and MSVC does not support
+// extra semicolons.
 struct py_treemanifest {
-  PyObject_HEAD;
+  PyObject_HEAD
 
   treemanifest tm;
 };
+// clang-format on
 
+// clang-format off
 struct py_newtreeiter {
-  PyObject_HEAD;
+  PyObject_HEAD
 
   FinalizeIterator iter;
 
   py_treemanifest *treemf;
 };
+// clang-format on
 
 static void newtreeiter_dealloc(py_newtreeiter *self);
 static PyObject *newtreeiter_iternext(py_newtreeiter *self);
@@ -74,13 +82,15 @@ static PyTypeObject newtreeiterType = {
     (iternextfunc)newtreeiter_iternext, /* tp_iternext: next() method */
 };
 
+// clang-format off
 struct py_subtreeiter {
-  PyObject_HEAD;
+  PyObject_HEAD
 
   SubtreeIterator iter;
 
   py_treemanifest *treemf;
 };
+// clang-format on
 
 static void subtreeiter_dealloc(py_subtreeiter *self);
 static PyObject *subtreeiter_iternext(py_subtreeiter *self);
@@ -119,8 +129,9 @@ static PyTypeObject subtreeiterType = {
  * the fileiter above because it lets us just call the constructor on
  * fileiter, which will automatically populate all the members of fileiter.
  */
+// clang-format off
 struct py_fileiter {
-  PyObject_HEAD;
+  PyObject_HEAD
 
   fileiter iter;
 
@@ -131,6 +142,7 @@ struct py_fileiter {
   // over it.
   const py_treemanifest *treemf;
 };
+// clang-format on
 
 static void fileiter_dealloc(py_fileiter *self);
 static PyObject *fileiter_iterentriesnext(py_fileiter *self);