share: make it possible to control the working copy format variant

A share will use the same format as its source for the store, but there are no
reason to not lets it control the working copy variant at creation time.

So we make it so.

Differential Revision: https://phab.mercurial-scm.org/D11892

mercurial/localrepo.py

@@ -1,4 +1,5 b''
 # localrepo.py - read/write repository class for mercurial
+# coding: utf-8
 #
 # Copyright 2005-2007 Olivia Mackall <[e-mail]>
 #
@@ -3661,17 +3662,36 b' def newreporequirements(ui, createopts):'
     if ui.configbool(b'format', b'use-share-safe'):
         requirements.add(requirementsmod.SHARESAFE_REQUIREMENT)
 
-    # If the repo is being created from a shared repository, we copy
-    # its requirements.
+    # if we are creating a share-repo¹  we have to handle requirement
+    # differently.
+    #
+    # [1] (i.e. reusing the store from another repository, just having a
+    # working copy)
     if b'sharedrepo' in createopts:
-        requirements = set(createopts[b'sharedrepo'].requirements)
+        source_requirements = set(createopts[b'sharedrepo'].requirements)
+
+        if requirementsmod.SHARESAFE_REQUIREMENT not in source_requirements:
+            # share to an old school repository, we have to copy the
+            # requirements and hope for the best.
+            requirements = source_requirements
+        else:
+            # We have control on the working copy only, so "copy" the non
+            # working copy part over, ignoring previous logic.
+            to_drop = set()
+            for req in requirements:
+                if req in requirementsmod.WORKING_DIR_REQUIREMENTS:
+                    continue
+                if req in source_requirements:
+                    continue
+                to_drop.add(req)
+            requirements -= to_drop
+            requirements |= source_requirements
+
         if createopts.get(b'sharedrelative'):
             requirements.add(requirementsmod.RELATIVE_SHARED_REQUIREMENT)
         else:
             requirements.add(requirementsmod.SHARED_REQUIREMENT)
 
-        return requirements
-
     return requirements
 
 

tests/test-share.t

@@ -284,3 +284,25 b' Test sharing a repository which was crea'
   $ hg share nostore sharednostore
   abort: cannot create shared repository as source was created with 'format.usestore' config disabled
   [255]
+
+Check that (safe) share can control wc-specific format variant at creation time
+-------------------------------------------------------------------------------
+
+#if no-rust
+
+  $ cat << EOF >> $HGRCPATH
+  > [storage]
+  > dirstate-v2.slow-path = allow
+  > EOF
+
+#endif
+
+  $ hg init repo-safe-d1 --config format.use-share-safe=yes --config format.exp-rc-dirstate-v2=no
+  $ hg debugformat -R repo-safe-d1 | grep dirstate-v2
+  dirstate-v2:         no
+
+  $ hg share repo-safe-d1 share-safe-d2 --config format.use-share-safe=yes --config format.exp-rc-dirstate-v2=yes
+  updating working directory
+  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  $ hg debugformat  -R share-safe-d2 | grep dirstate-v2
+  dirstate-v2:        yes