D5166: localrepo: support marking repos as having shallow file storage

[indygreg (Gregory Szorc)]

indygreg created this revision.
Herald added a subscriber: mercurial-devel.
Herald added a reviewer: hg-reviewers.

REVISION SUMMARY
  Various operations against repositories need to know if repository
  storage is full or partial. For example, a checkout (including possibly
  a widening of a sparse checkout), needs to know if it can assume all file
  revisions are available or whether to look for missing revisions first.
  
  This commit lays the plumbing for doing that.
  
  We define a repo creation option that indicates that shallow file storage
  is desired.
  
  The SQLite store uses this creation option to add an extra repo requirement
  indicating file storage is shallow.
  
  A new repository feature has been added to indicate that file storage is
  shallow. The SQLite store adds this feature when the shallow file store
  requirement is present.
  
  Code can now look at repo.features to determine if repo file storage may
  be shallow and take additional actions if so.
  
  While we're here, we also teach the SQLite store to handle the narrow repo
  requirement, which gets added when making narrow clones.

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D5166

AFFECTED FILES
  hgext/sqlitestore.py
  mercurial/hg.py
  mercurial/localrepo.py
  mercurial/repository.py

CHANGE DETAILS

diff --git a/mercurial/repository.py b/mercurial/repository.py
--- a/mercurial/repository.py
+++ b/mercurial/repository.py
@@ -29,6 +29,8 @@
 REPO_FEATURE_LFS = b'lfs'
 # Repository supports being stream cloned.
 REPO_FEATURE_STREAM_CLONE = b'streamclone'
+# Files storage may lack data for all ancestors.
+REPO_FEATURE_SHALLOW_FILE_STORAGE = b'shallowfilestorage'
 
 REVISION_FLAG_CENSORED = 1 << 15
 REVISION_FLAG_ELLIPSIS = 1 << 14
diff --git a/mercurial/localrepo.py b/mercurial/localrepo.py
--- a/mercurial/localrepo.py
+++ b/mercurial/localrepo.py
@@ -2922,6 +2922,7 @@
         'sharedrepo',
         'sharedrelative',
         'shareditems',
+        'shallowfilestore',
     }
 
     return {k: v for k, v in createopts.items() if k not in known}
@@ -2949,6 +2950,9 @@
        is stored as an absolute path.
     shareditems
        Set of items to share to the new repository (in addition to storage).
+    shallowfilestore
+       Indicates that storage for files should be shallow (not all ancestor
+       revisions are known).
     """
     createopts = defaultcreateopts(ui, createopts=createopts)
 
diff --git a/mercurial/hg.py b/mercurial/hg.py
--- a/mercurial/hg.py
+++ b/mercurial/hg.py
@@ -578,6 +578,9 @@
 
         createopts['narrowfiles'] = True
 
+    if depth:
+        createopts['shallowfilestore'] = True
+
     if srcpeer.capable(b'lfs-serve'):
         # Repository creation honors the config if it disabled the extension, so
         # we can't just announce that lfs will be enabled.  This check avoids
diff --git a/hgext/sqlitestore.py b/hgext/sqlitestore.py
--- a/hgext/sqlitestore.py
+++ b/hgext/sqlitestore.py
@@ -101,6 +101,7 @@
 REQUIREMENT_ZSTD = b'exp-sqlite-comp-001=zstd'
 REQUIREMENT_ZLIB = b'exp-sqlite-comp-001=zlib'
 REQUIREMENT_NONE = b'exp-sqlite-comp-001=none'
+REQUIREMENT_SHALLOW_FILES = b'exp-sqlite-shallow-files'
 
 CURRENT_SCHEMA_VERSION = 1
 
@@ -1014,6 +1015,8 @@
 
     supported.add(REQUIREMENT_ZLIB)
     supported.add(REQUIREMENT_NONE)
+    supported.add(REQUIREMENT_SHALLOW_FILES)
+    supported.add(repository.NARROW_REQUIREMENT)
 
 def newreporequirements(orig, ui, createopts):
     if createopts['backend'] != 'sqlite':
@@ -1030,6 +1033,7 @@
     known = {
         'narrowfiles',
         'backend',
+        'shallowfilestore',
     }
 
     unsupported = set(createopts) - known
@@ -1061,6 +1065,9 @@
         raise error.Abort(_('unknown compression engine defined in '
                             'storage.sqlite.compression: %s') % compression)
 
+    if createopts.get('shallowfilestore'):
+        requirements.add(REQUIREMENT_SHALLOW_FILES)
+
     return requirements
 
 @interfaceutil.implementer(repository.ilocalrepositoryfilestorage)
@@ -1082,12 +1089,15 @@
 
         return sqlitefilestore(self._dbconn, path, compression)
 
-def makefilestorage(orig, requirements, **kwargs):
+def makefilestorage(orig, requirements, features, **kwargs):
     """Produce a type conforming to ``ilocalrepositoryfilestorage``."""
     if REQUIREMENT in requirements:
+        if REQUIREMENT_SHALLOW_FILES in requirements:
+            features.add(repository.REPO_FEATURE_SHALLOW_FILE_STORAGE)
+
         return sqlitefilestorage
     else:
-        return orig(requirements=requirements, **kwargs)
+        return orig(requirements=requirements, features=features, **kwargs)
 
 def makemain(orig, ui, requirements, **kwargs):
     if REQUIREMENT in requirements:



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