sparse: add a requirement when a repository uses sparse (BC)
authorGregory Szorc <gregory.szorc@gmail.com>
Mon, 17 Jul 2017 11:45:38 -0700
changeset 33556 22371eabb3b1
parent 33555 6755b719048c
child 33557 875b054e5b95
sparse: add a requirement when a repository uses sparse (BC) The presence of a sparse checkout can confuse legacy clients or clients without sparse enabled for reasons that should be obvious. This commit introduces a new repository requirement that tracks whether sparse is enabled. The requirement is added when a sparse config is activated and removed when the sparse config is reset. The localrepository constructor has been taught to not open repos with this requirement unless the sparse feature is enabled. It yields a more actionable error message than what you would get if the lockout were handled strictly at the requirements verification phase. Old clients that aren't sparse aware will see the generic "repository requires features unknown to this Mercurial" error, however. The new requirement has "exp" in its name to reflect the experimental nature of sparse. There's a chance that the eventual non-experimental feature won't change significantly and we could have squatted on the "sparse" requirement without ill effect. If that happens, we can teach new clients to still recognize the old name. But I suspect we'll sneak in some BC and we'll want a new requirement to convey new meaning. Differential Revision: https://phab.mercurial-scm.org/D110
mercurial/help/internals/requirements.txt
mercurial/localrepo.py
mercurial/sparse.py
tests/test-sparse-requirement.t
--- a/mercurial/help/internals/requirements.txt	Mon Jul 17 11:21:23 2017 -0700
+++ b/mercurial/help/internals/requirements.txt	Mon Jul 17 11:45:38 2017 -0700
@@ -117,3 +117,14 @@
 Support for this requirement was added in Mercurial 3.4 (released
 August 2015). The requirement is currently experimental and is
 disabled by default.
+
+exp-sparse
+==========
+
+The working directory is sparse (only contains a subset of files).
+
+Support for this requirement was added in Mercurial 4.3 (released
+August 2017). This requirement and feature are experimental and may
+disappear in a future Mercurial release. The requirement will only
+be present on repositories that have opted in to a sparse working
+directory.
--- a/mercurial/localrepo.py	Mon Jul 17 11:21:23 2017 -0700
+++ b/mercurial/localrepo.py	Mon Jul 17 11:45:38 2017 -0700
@@ -288,6 +288,7 @@
         'shared',
         'relshared',
         'dotencode',
+        'exp-sparse',
     }
     openerreqs = {
         'revlogv1',
@@ -419,6 +420,11 @@
             if inst.errno != errno.ENOENT:
                 raise
 
+        if 'exp-sparse' in self.requirements and not sparse.enabled:
+            raise error.RepoError(_('repository is using sparse feature but '
+                                    'sparse is not enabled; enable the '
+                                    '"sparse" extensions to access'))
+
         self.store = store.store(
                 self.requirements, self.sharedpath, vfsmod.vfs)
         self.spath = self.store.path
--- a/mercurial/sparse.py	Mon Jul 17 11:21:23 2017 -0700
+++ b/mercurial/sparse.py	Mon Jul 17 11:45:38 2017 -0700
@@ -18,6 +18,7 @@
     match as matchmod,
     merge as mergemod,
     pycompat,
+    scmutil,
     util,
 )
 
@@ -522,13 +523,14 @@
     prunetemporaryincludes(repo)
 
 def _updateconfigandrefreshwdir(repo, includes, excludes, profiles,
-                                force=False):
+                                force=False, removing=False):
     """Update the sparse config and working directory state."""
     raw = repo.vfs.tryread('sparse')
     oldincludes, oldexcludes, oldprofiles = parseconfig(repo.ui, raw)
 
     oldstatus = repo.status()
     oldmatch = matcher(repo)
+    oldrequires = set(repo.requirements)
 
     # TODO remove this try..except once the matcher integrates better
     # with dirstate. We currently have to write the updated config
@@ -538,11 +540,21 @@
     # updated. But this requires massive rework to matcher() and its
     # consumers.
 
-    writeconfig(repo, includes, excludes, profiles)
+    if 'exp-sparse' in oldrequires and removing:
+        repo.requirements.discard('exp-sparse')
+        scmutil.writerequires(repo.vfs, repo.requirements)
+    elif 'exp-sparse' not in oldrequires:
+        repo.requirements.add('exp-sparse')
+        scmutil.writerequires(repo.vfs, repo.requirements)
 
     try:
+        writeconfig(repo, includes, excludes, profiles)
         return refreshwdir(repo, oldstatus, oldmatch, force=force)
     except Exception:
+        if repo.requirements != oldrequires:
+            repo.requirements.clear()
+            repo.requirements |= oldrequires
+            scmutil.writerequires(repo.vfs, repo.requirements)
         writeconfig(repo, oldincludes, oldexcludes, oldprofiles)
         raise
 
@@ -647,7 +659,8 @@
                         len(oldexclude - newexclude))
 
         fcounts = map(len, _updateconfigandrefreshwdir(
-            repo, newinclude, newexclude, newprofiles, force=force))
+            repo, newinclude, newexclude, newprofiles, force=force,
+            removing=reset))
 
         printchanges(repo.ui, opts, profilecount, includecount,
                      excludecount, *fcounts)
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tests/test-sparse-requirement.t	Mon Jul 17 11:45:38 2017 -0700
@@ -0,0 +1,65 @@
+  $ hg init repo
+  $ cd repo
+
+  $ touch a.html b.html c.py d.py
+
+  $ cat > frontend.sparse << EOF
+  > [include]
+  > *.html
+  > EOF
+
+  $ hg -q commit -A -m initial
+
+  $ echo 1 > a.html
+  $ echo 1 > c.py
+  $ hg commit -m 'commit 1'
+
+Enable sparse profile
+
+  $ cat .hg/requires
+  dotencode
+  fncache
+  generaldelta
+  revlogv1
+  store
+
+  $ hg debugsparse --config extensions.sparse= --enable-profile frontend.sparse
+  $ ls
+  a.html
+  b.html
+
+Requirement for sparse added when sparse is enabled
+
+  $ cat .hg/requires
+  dotencode
+  exp-sparse
+  fncache
+  generaldelta
+  revlogv1
+  store
+
+Client without sparse enabled reacts properly
+
+  $ hg files
+  abort: repository is using sparse feature but sparse is not enabled; enable the "sparse" extensions to access!
+  [255]
+
+Requirement for sparse is removed when sparse is disabled
+
+  $ hg debugsparse --reset --config extensions.sparse=
+
+  $ cat .hg/requires
+  dotencode
+  fncache
+  generaldelta
+  revlogv1
+  store
+
+And client without sparse can access
+
+  $ hg files
+  a.html
+  b.html
+  c.py
+  d.py
+  frontend.sparse