D11764: rhg: add support for narrow clones and sparse checkouts

[aalekseyev (Arseniy Alekseyev)]

aalekseyev created this revision.
Herald added a reviewer: hg-reviewers.
Herald added a subscriber: mercurial-patches.

REVISION SUMMARY
  This adds a minimal support that can be implemented without parsing the narrowspec.
  We can parse the narrowspec and add support for more operations later.
  
  The reason we need so few code changes is as follows:
  
  Most operations need no special treatment of sparse because
  some of them only read dirstate (`rhg files` without `-r`),
  which bakes in the filtering,
  some of them only read store (`rhg files -r`, `rhg cat`),
  and some of them read no data at all (`rhg root`, `rhg debugrequirements`).
  
  `status` is the command that might care about sparse, so we just disable
  rhg on it.
  
  For narrow clones, `rhg files` clearly needs the narrowspec to work
  correctly, so we fall back.
  `rhg cat` seems to work consistently with `hg cat` if the file exists.
  If the file is hidden by narrow spec, the error message is different and confusing, so
  that's something that we should improve in follow-up patches.

REPOSITORY
  rHG Mercurial

BRANCH
  default

REVISION DETAIL
  https://phab.mercurial-scm.org/D11764

AFFECTED FILES
  rust/hg-core/src/repo.rs
  rust/hg-core/src/requirements.rs
  rust/rhg/src/commands/files.rs
  rust/rhg/src/commands/status.rs
  rust/rhg/src/main.rs
  tests/test-rhg-sparse-narrow.t

CHANGE DETAILS

diff --git a/tests/test-rhg-sparse-narrow.t b/tests/test-rhg-sparse-narrow.t
new file mode 100644
--- /dev/null
+++ b/tests/test-rhg-sparse-narrow.t
@@ -0,0 +1,120 @@
+#require rhg
+
+  $ NO_FALLBACK="env RHG_ON_UNSUPPORTED=abort"
+
+Rhg works well when sparse working copy is enabled.
+
+  $ cd "$TESTTMP"
+  $ hg init repo-sparse
+  $ cd repo-sparse
+  $ cat > .hg/hgrc <<EOF
+  > [extensions]
+  > sparse=
+  > EOF
+
+  $ echo a > show
+  $ echo x > hide
+  $ mkdir dir1 dir2
+  $ echo x > dir1/x
+  $ echo y > dir1/y
+  $ echo z > dir2/z
+
+  $ hg ci -Aqm 'initial'
+  $ hg debugsparse --include 'show'
+  $ ls -A
+  .hg
+  show
+
+  $ tip=$(hg log -r . --template '{node}')
+  $ $NO_FALLBACK rhg files -r "$tip"
+  dir1/x
+  dir1/y
+  dir2/z
+  hide
+  show
+  $ $NO_FALLBACK rhg files
+  show
+
+  $ $NO_FALLBACK rhg cat -r "$tip" hide
+  x
+
+  $ cd ..
+
+We support most things when narrow is enabled, too, with a couple of caveats.
+
+  $ . "$TESTDIR/narrow-library.sh"
+  $ real_hg=$RHG_FALLBACK_EXECUTABLE
+
+  $ cat >> $HGRCPATH <<EOF
+  > [extensions]
+  > narrow=
+  > EOF
+
+  $ hg clone --narrow  ./repo-sparse repo-narrow --include dir1
+  requesting all changes
+  adding changesets
+  adding manifests
+  adding file changes
+  added 1 changesets with 2 changes to 2 files
+  new changesets 6d714a4a2998
+  updating to branch default
+  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
+
+  $ cd repo-narrow
+
+  $ $NO_FALLBACK rhg cat -r "$tip" dir1/x
+  x
+  $ "$real_hg" cat -r "$tip" dir1/x
+  x
+
+TODO: bad error message
+
+  $ $NO_FALLBACK rhg cat -r "$tip" hide
+  abort: invalid revision identifier: 6d714a4a2998cbfd0620db44da58b749f6565d63
+  [255]
+  $ "$real_hg" cat -r "$tip" hide
+  [1]
+
+A naive implementation of [rhg files] leaks the paths that are supposed to be
+hidden by narrow, so we just fall back to hg.
+
+  $ $NO_FALLBACK rhg files -r "$tip"
+  unsupported feature: rhg files -r <rev> is not support in narrow clones
+  [252]
+  $ "$real_hg" files -r "$tip"
+  dir1/x
+  dir1/y
+
+Hg status needs to do some filtering based on narrow spec, so we don't
+support it in rhg for narrow clones yet.
+
+  $ mkdir dir2
+  $ touch dir2/q
+  $ "$real_hg" status
+  $ $NO_FALLBACK rhg --config rhg.status=true status
+  unsupported feature: rhg status is not supported for sparse checkouts or narrow clones yet
+  [252]
+
+Adding "orphaned" index files:
+
+  $ (cd ..; cp {repo-sparse,repo-narrow}/.hg/store/data/hide.i)
+  $ (cd ..; mkdir repo-narrow/.hg/store/data/dir2; cp {repo-sparse,repo-narrow}/.hg/store/data/dir2/z.i)
+  $ "$real_hg" verify
+  checking changesets
+  checking manifests
+  crosschecking files in changesets and manifests
+  checking files
+  checked 1 changesets with 2 changes to 2 files
+
+  $ "$real_hg" files -r "$tip"
+  dir1/x
+  dir1/y
+
+# TODO: even though [hg files] hides the orphaned dir2/z, [hg cat] still shows it.
+# rhg has the same issue, but at least it's not specific to rhg.
+# This is despite [hg verify] succeeding above.
+
+  $ $NO_FALLBACK rhg cat -r "$tip" dir2/z
+  z
+  $ "$real_hg" cat -r "$tip" dir2/z
+  z
diff --git a/rust/rhg/src/main.rs b/rust/rhg/src/main.rs
--- a/rust/rhg/src/main.rs
+++ b/rust/rhg/src/main.rs
@@ -588,7 +588,8 @@
     }
 }
 
-const SUPPORTED_EXTENSIONS: &[&[u8]] = &[b"blackbox", b"share"];
+const SUPPORTED_EXTENSIONS: &[&[u8]] =
+    &[b"blackbox", b"share", b"sparse", b"narrow"];
 
 fn check_extensions(config: &Config) -> Result<(), CommandError> {
     let enabled = config.get_section_keys(b"extensions");
diff --git a/rust/rhg/src/commands/status.rs b/rust/rhg/src/commands/status.rs
--- a/rust/rhg/src/commands/status.rs
+++ b/rust/rhg/src/commands/status.rs
@@ -174,6 +174,12 @@
     };
 
     let repo = invocation.repo?;
+    if repo.has_sparse() || repo.has_narrow() {
+        return Err(CommandError::unsupported(
+            "rhg status is not supported for sparse checkouts or narrow clones yet"
+        ));
+    }
+
     let mut dmap = repo.dirstate_map_mut()?;
 
     let options = StatusOptions {
diff --git a/rust/rhg/src/commands/files.rs b/rust/rhg/src/commands/files.rs
--- a/rust/rhg/src/commands/files.rs
+++ b/rust/rhg/src/commands/files.rs
@@ -40,6 +40,11 @@
 
     let repo = invocation.repo?;
     if let Some(rev) = rev {
+        if repo.has_narrow() {
+            return Err(CommandError::unsupported(
+                "rhg files -r <rev> is not support in narrow clones",
+            ));
+        }
         let files = list_rev_tracked_files(repo, rev).map_err(|e| (e, rev))?;
         display_files(invocation.ui, repo, files.iter())
     } else {
diff --git a/rust/hg-core/src/requirements.rs b/rust/hg-core/src/requirements.rs
--- a/rust/hg-core/src/requirements.rs
+++ b/rust/hg-core/src/requirements.rs
@@ -88,6 +88,8 @@
     // When it starts writing to the repository, it’ll need to either keep the
     // persistent nodemap up to date or remove this entry:
     NODEMAP_REQUIREMENT,
+    SPARSE_REQUIREMENT,
+    NARROW_REQUIREMENT,
 ];
 
 // Copied from mercurial/requirements.py:
diff --git a/rust/hg-core/src/repo.rs b/rust/hg-core/src/repo.rs
--- a/rust/hg-core/src/repo.rs
+++ b/rust/hg-core/src/repo.rs
@@ -248,6 +248,14 @@
             .contains(requirements::DIRSTATE_V2_REQUIREMENT)
     }
 
+    pub fn has_sparse(&self) -> bool {
+        self.requirements.contains(requirements::SPARSE_REQUIREMENT)
+    }
+
+    pub fn has_narrow(&self) -> bool {
+        self.requirements.contains(requirements::NARROW_REQUIREMENT)
+    }
+
     fn dirstate_file_contents(&self) -> Result<Vec<u8>, HgError> {
         Ok(self
             .hg_vfs()



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