# HG changeset patch
# User Simon Sapin <simon.sapin@octobus.net>
# Date 2021-07-16 16:42:20
# Node ID b4f83c9e790528efcf8162359f34523148efd2f7
# Parent  7e78c72ee3ea436d6d366da05861a0d0b37cba30

dirstate-v2: Add support when Rust is not enabled

This wires into `dirstatemap` the parser and serializer added in previous
changesets. The memory representation is still the same, with a flat `dict`
for `DirstateItem`s and another one for copy sources. Serialization always
creates a new dirstate-v2 data file and does not support (when Rust is not
enabled) appending to an existing one, since we don’t keep track of which
tree nodes are new or modified. Instead the tree is reconstructed during
serialization.

Differential Revision: https://phab.mercurial-scm.org/D11520

diff --git a/mercurial/dirstate.py b/mercurial/dirstate.py
--- a/mercurial/dirstate.py
+++ b/mercurial/dirstate.py
@@ -39,8 +39,6 @@ from .interfaces import (
 parsers = policy.importmod('parsers')
 rustmod = policy.importrust('dirstate')
 
-SUPPORTS_DIRSTATE_V2 = rustmod is not None
-
 propertycache = util.propertycache
 filecache = scmutil.filecache
 _rangemask = dirstatemap.rangemask
diff --git a/mercurial/dirstatemap.py b/mercurial/dirstatemap.py
--- a/mercurial/dirstatemap.py
+++ b/mercurial/dirstatemap.py
@@ -332,15 +332,6 @@ class dirstatemap(_dirstatemapcommon):
       denormalized form that they appear as in the dirstate.
     """
 
-    def __init__(self, ui, opener, root, nodeconstants, use_dirstate_v2):
-        super(dirstatemap, self).__init__(
-            ui, opener, root, nodeconstants, use_dirstate_v2
-        )
-        if self._use_dirstate_v2:
-            msg = "Dirstate V2 not supportedi"
-            msg += "(should have detected unsupported requirement)"
-            raise error.ProgrammingError(msg)
-
     ### Core data storage and access
 
     @propertycache
@@ -406,19 +397,17 @@ class dirstatemap(_dirstatemapcommon):
             self._opener.join(self._filename)
         )
 
-        try:
-            fp = self._opendirstatefile()
-            try:
-                st = fp.read()
-            finally:
-                fp.close()
-        except IOError as err:
-            if err.errno != errno.ENOENT:
-                raise
-            return
+        if self._use_dirstate_v2:
+            if not self.docket.uuid:
+                return
+            st = self._opener.read(self.docket.data_filename())
+        else:
+            st = self._readdirstatefile()
+
         if not st:
             return
 
+        # TODO: adjust this estimate for dirstate-v2
         if util.safehasattr(parsers, b'dict_new_presized'):
             # Make an estimate of the number of files in the dirstate based on
             # its size. This trades wasting some memory for avoiding costly
@@ -440,8 +429,14 @@ class dirstatemap(_dirstatemapcommon):
         # parsing the dirstate.
         #
         # (we cannot decorate the function directly since it is in a C module)
-        parse_dirstate = util.nogc(parsers.parse_dirstate)
-        p = parse_dirstate(self._map, self.copymap, st)
+        if self._use_dirstate_v2:
+            p = self.docket.parents
+            meta = self.docket.tree_metadata
+            parse_dirstate = util.nogc(v2.parse_dirstate)
+            parse_dirstate(self._map, self.copymap, st, meta)
+        else:
+            parse_dirstate = util.nogc(parsers.parse_dirstate)
+            p = parse_dirstate(self._map, self.copymap, st)
         if not self._dirtyparents:
             self.setparents(*p)
 
@@ -450,10 +445,16 @@ class dirstatemap(_dirstatemapcommon):
         self.__getitem__ = self._map.__getitem__
         self.get = self._map.get
 
-    def write(self, _tr, st, now):
-        d = parsers.pack_dirstate(self._map, self.copymap, self.parents(), now)
-        st.write(d)
-        st.close()
+    def write(self, tr, st, now):
+        if self._use_dirstate_v2:
+            packed, meta = v2.pack_dirstate(self._map, self.copymap, now)
+            self.write_v2_no_append(tr, st, meta, packed)
+        else:
+            packed = parsers.pack_dirstate(
+                self._map, self.copymap, self.parents(), now
+            )
+            st.write(packed)
+            st.close()
         self._dirtyparents = False
 
     @propertycache
diff --git a/mercurial/localrepo.py b/mercurial/localrepo.py
--- a/mercurial/localrepo.py
+++ b/mercurial/localrepo.py
@@ -917,9 +917,6 @@ def gathersupportedrequirements(ui):
     # Start with all requirements supported by this file.
     supported = set(localrepository._basesupported)
 
-    if dirstate.SUPPORTS_DIRSTATE_V2:
-        supported.add(requirementsmod.DIRSTATE_V2_REQUIREMENT)
-
     # Execute ``featuresetupfuncs`` entries if they belong to an extension
     # relevant to this ui instance.
     modules = {m.__name__ for n, m in extensions.extensions(ui)}
@@ -1266,6 +1263,7 @@ class localrepository(object):
         requirementsmod.NODEMAP_REQUIREMENT,
         bookmarks.BOOKMARKS_IN_STORE_REQUIREMENT,
         requirementsmod.SHARESAFE_REQUIREMENT,
+        requirementsmod.DIRSTATE_V2_REQUIREMENT,
     }
     _basesupported = supportedformats | {
         requirementsmod.STORE_REQUIREMENT,
@@ -3609,15 +3607,7 @@ def newreporequirements(ui, createopts):
     # experimental config: format.exp-dirstate-v2
     # Keep this logic in sync with `has_dirstate_v2()` in `tests/hghave.py`
     if ui.configbool(b'format', b'exp-dirstate-v2'):
-        if dirstate.SUPPORTS_DIRSTATE_V2:
-            requirements.add(requirementsmod.DIRSTATE_V2_REQUIREMENT)
-        else:
-            raise error.Abort(
-                _(
-                    b"dirstate v2 format requested by config "
-                    b"but not supported (requires Rust extensions)"
-                )
-            )
+        requirements.add(requirementsmod.DIRSTATE_V2_REQUIREMENT)
 
     # experimental config: format.exp-use-copies-side-data-changeset
     if ui.configbool(b'format', b'exp-use-copies-side-data-changeset'):
diff --git a/tests/test-dirstate-race.t b/tests/test-dirstate-race.t
--- a/tests/test-dirstate-race.t
+++ b/tests/test-dirstate-race.t
@@ -1,7 +1,6 @@
 #testcases dirstate-v1 dirstate-v2
 
 #if dirstate-v2
-#require rust
   $ echo '[format]' >> $HGRCPATH
   $ echo 'exp-dirstate-v2=1' >> $HGRCPATH
 #endif
diff --git a/tests/test-dirstate-race2.t b/tests/test-dirstate-race2.t
--- a/tests/test-dirstate-race2.t
+++ b/tests/test-dirstate-race2.t
@@ -1,7 +1,6 @@
 #testcases dirstate-v1 dirstate-v2
 
 #if dirstate-v2
-#require rust
   $ echo '[format]' >> $HGRCPATH
   $ echo 'exp-dirstate-v2=1' >> $HGRCPATH
 #endif
diff --git a/tests/test-dirstate.t b/tests/test-dirstate.t
--- a/tests/test-dirstate.t
+++ b/tests/test-dirstate.t
@@ -1,7 +1,6 @@
 #testcases dirstate-v1 dirstate-v2
 
 #if dirstate-v2
-#require rust
   $ echo '[format]' >> $HGRCPATH
   $ echo 'exp-dirstate-v2=1' >> $HGRCPATH
 #endif
diff --git a/tests/test-hgignore.t b/tests/test-hgignore.t
--- a/tests/test-hgignore.t
+++ b/tests/test-hgignore.t
@@ -1,7 +1,6 @@
 #testcases dirstate-v1 dirstate-v2
 
 #if dirstate-v2
-#require rust
   $ echo '[format]' >> $HGRCPATH
   $ echo 'exp-dirstate-v2=1' >> $HGRCPATH
 #endif
@@ -397,9 +396,10 @@ Windows paths are accepted on input
 
 #endif
 
-#if dirstate-v2
+#if dirstate-v2 rust
 
 Check the hash of ignore patterns written in the dirstate
+This is an optimization that is only relevant when using the Rust extensions
 
   $ hg status > /dev/null
   $ cat .hg/testhgignore .hg/testhgignorerel .hgignore dir2/.hgignore dir1/.hgignore dir1/.hgignoretwo | $TESTDIR/f --sha1
diff --git a/tests/test-permissions.t b/tests/test-permissions.t
--- a/tests/test-permissions.t
+++ b/tests/test-permissions.t
@@ -3,7 +3,6 @@
 #testcases dirstate-v1 dirstate-v2
 
 #if dirstate-v2
-#require rust
   $ echo '[format]' >> $HGRCPATH
   $ echo 'exp-dirstate-v2=1' >> $HGRCPATH
 #endif
diff --git a/tests/test-purge.t b/tests/test-purge.t
--- a/tests/test-purge.t
+++ b/tests/test-purge.t
@@ -1,7 +1,6 @@
 #testcases dirstate-v1 dirstate-v2
 
 #if dirstate-v2
-#require rust
   $ echo '[format]' >> $HGRCPATH
   $ echo 'exp-dirstate-v2=1' >> $HGRCPATH
 #endif
diff --git a/tests/test-status.t b/tests/test-status.t
--- a/tests/test-status.t
+++ b/tests/test-status.t
@@ -1,13 +1,6 @@
 #testcases dirstate-v1 dirstate-v2
 
-#if no-rust
-  $ hg init repo0 --config format.exp-dirstate-v2=1
-  abort: dirstate v2 format requested by config but not supported (requires Rust extensions)
-  [255]
-#endif
-
 #if dirstate-v2
-#require rust
   $ echo '[format]' >> $HGRCPATH
   $ echo 'exp-dirstate-v2=1' >> $HGRCPATH
 #endif
@@ -743,7 +736,7 @@ When a directory containing a tracked fi
 if also listing unknowns.
 The tree-based dirstate and status algorithm fix this:
 
-#if symlink no-dirstate-v1
+#if symlink no-dirstate-v1 rust
 
   $ cd ..
   $ hg init issue6335
@@ -759,11 +752,11 @@ The tree-based dirstate and status algor
   ? bar/a
   ? foo
 
-  $ hg status -c  # incorrect output with `dirstate-v1`
+  $ hg status -c  # incorrect output without the Rust implementation
   $ hg status -cu
   ? bar/a
   ? foo
-  $ hg status -d  # incorrect output with `dirstate-v1`
+  $ hg status -d  # incorrect output without the Rust implementation
   ! foo/a
   $ hg status -du
   ! foo/a
@@ -910,7 +903,7 @@ Check using include flag while listing i
   I B.hs
   I ignored-folder/ctest.hs
 
-#if dirstate-v2
+#if rust dirstate-v2
 
 Check read_dir caching
 
diff --git a/tests/test-symlinks.t b/tests/test-symlinks.t
--- a/tests/test-symlinks.t
+++ b/tests/test-symlinks.t
@@ -3,7 +3,6 @@
 #testcases dirstate-v1 dirstate-v2
 
 #if dirstate-v2
-#require rust
   $ echo '[format]' >> $HGRCPATH
   $ echo 'exp-dirstate-v2=1' >> $HGRCPATH
 #endif