changelog: disallow delayed write on inline changesets

changelog: disallow delayed write on inline changesets

Since this will never happens, we can make the situation invalid and to stop to
handling the associated the case.

This simplify the random access file reading too.

--- a/mercurial/revlog.py	Mon Dec 11 22:27:59 2023 +0100
+++ b/mercurial/revlog.py	Thu Dec 07 02:07:16 2023 +0100
@@ -367,7 +367,7 @@
         self.opener = opener
         self.index = index
 
-        self.__index_file = index_file
+        self.index_file = index_file
         self.data_file = data_file
         self.sidedata_file = sidedata_file
         self.inline = inline
@@ -416,16 +416,6 @@
 
         self._delay_buffer = None
 
-    @property
-    def index_file(self):
-        return self.__index_file
-
-    @index_file.setter
-    def index_file(self, new_index_file):
-        self.__index_file = new_index_file
-        if self.inline:
-            self._segmentfile.filename = new_index_file
-
     def __len__(self):
         return len(self.index)
 
@@ -652,6 +642,9 @@
         """Context manager that keeps data and sidedata files open for reading"""
         if len(self.index) == 0:
             yield  # nothing to be read
+        elif self._delay_buffer is not None and self.inline:
+            msg = "revlog with delayed write should not be inline"
+            raise error.ProgrammingError(msg)
         else:
             with self._segmentfile.reading():
                 with self._segmentfile_sidedata.reading():
@@ -1137,18 +1130,16 @@
                 ifh.write(entry)
             else:
                 self._delay_buffer.append(entry)
+        elif self._delay_buffer is not None:
+            msg = b'invalid delayed write on inline revlog'
+            raise error.ProgrammingError(msg)
         else:
             offset += curr * self.index.entry_size
             transaction.add(self.canonical_index_file, offset)
             assert not sidedata
-            if self._delay_buffer is None:
-                ifh.write(entry)
-                ifh.write(data[0])
-                ifh.write(data[1])
-            else:
-                self._delay_buffer.append(entry)
-                self._delay_buffer.append(data[0])
-                self._delay_buffer.append(data[1])
+            ifh.write(entry)
+            ifh.write(data[0])
+            ifh.write(data[1])
         return (
             ifh.tell(),
             dfh.tell() if dfh else None,
@@ -1160,6 +1151,9 @@
 
     def delay(self):
         assert not self.is_open
+        if self.inline:
+            msg = "revlog with delayed write should not be inline"
+            raise error.ProgrammingError(msg)
         if self._delay_buffer is not None or self._orig_index_file is not None:
             # delay or divert already in place
             return None
@@ -1173,12 +1167,13 @@
             return self.index_file
         else:
             self._delay_buffer = []
-            if self.inline:
-                self._segmentfile._delay_buffer = self._delay_buffer
             return None
 
     def write_pending(self):
         assert not self.is_open
+        if self.inline:
+            msg = "revlog with delayed write should not be inline"
+            raise error.ProgrammingError(msg)
         if self._orig_index_file is not None:
             return None, True
         any_pending = False
@@ -1195,16 +1190,15 @@
                 ifh.write(b"".join(self._delay_buffer))
             any_pending = True
         self._delay_buffer = None
-        if self.inline:
-            self._segmentfile._delay_buffer = self._delay_buffer
-        else:
-            assert self._segmentfile._delay_buffer is None
         self._orig_index_file = self.index_file
         self.index_file = pending_index_file
         return self.index_file, any_pending
 
     def finalize_pending(self):
         assert not self.is_open
+        if self.inline:
+            msg = "revlog with delayed write should not be inline"
+            raise error.ProgrammingError(msg)
 
         delay = self._delay_buffer is not None
         divert = self._orig_index_file is not None
@@ -1216,7 +1210,7 @@
                 with self.opener(self.index_file, b'r+') as ifh:
                     ifh.seek(0, os.SEEK_END)
                     ifh.write(b"".join(self._delay_buffer))
-            self._segmentfile._delay_buffer = self._delay_buffer = None
+            self._delay_buffer = None
         elif divert:
             if self.opener.exists(self.index_file):
                 self.opener.rename(
@@ -2831,7 +2825,7 @@
         """
         tiprev = len(self) - 1
         total_size = self.start(tiprev) + self.length(tiprev)
-        if not self._inline or total_size < _maxinline:
+        if not self._inline or (self._may_inline and total_size < _maxinline):
             return
 
         if self._docket is not None:

--- a/mercurial/revlogutils/randomaccessfile.py	Mon Dec 11 22:27:59 2023 +0100
+++ b/mercurial/revlogutils/randomaccessfile.py	Thu Dec 07 02:07:16 2023 +0100
@@ -116,8 +116,6 @@
         if initial_cache:
             self._cached_chunk_position, self._cached_chunk = initial_cache
 
-        self._delay_buffer = None
-
     def clear_cache(self):
         self._cached_chunk = b''
         self._cached_chunk_position = 0
@@ -133,12 +131,7 @@
 
     def _open(self, mode=b'r'):
         """Return a file object"""
-        if self._delay_buffer is None:
-            return self.opener(self.filename, mode=mode)
-        else:
-            return appender(
-                self.opener, self.filename, mode, self._delay_buffer
-            )
+        return self.opener(self.filename, mode=mode)
 
     @contextlib.contextmanager
     def _read_handle(self):