commands: document the layering violation in `manifest --all`

This commit fixes the last test failures when using the simple
store extension!

It turns out that `hg manifest --all` locks the repo and scans for
revlogs. This feature was added by 71938479eff9 in 2011. I am
debating changing the behavior. But that can occur in another
commit.

As part of debugging this, I realized that test-manifest.t is the
only meaningful tester of `hg manifest --all` and that test was
improperly disabled when bundlerepos aren't supported. The test is
testing manifest behavior, not whether you can `hg pull` from a
bundle. So I changed the test to `hg unbundle` instead.

FWIW, I wasted a non-trivial amount of time tracking down this
failure. I thought the issue involved Git, which is why I refactored
the test to be more deterministic. Never in my mind would I have
guessed that code in `hg manifest` would scan revlogs. I should have
looked there to begin with. Doh.

Differential Revision: https://phab.mercurial-scm.org/D3118

mercurial/commands.py

@@ -3492,6 +3492,8 b' def manifest(ui, repo, node=None, rev=No'
             raise error.Abort(_("can't specify a revision with --all"))
 
         res = []
+        # TODO this is a massive layering violation. It assumes the repo is
+        # backed by revlogs with a well-defined naming scheme.
         prefix = "data/"
         suffix = ".i"
         plen = len(prefix)

tests/test-convert-git.t

@@ -878,7 +878,7 b' skip submodules in the conversion'
 
   $ hg convert -q git-repo6 no-submodules --config convert.git.skipsubmodules=True
   $ hg -R no-submodules manifest --all
-  .gitmodules-renamed
+  .gitmodules-renamed (no-reposimplestore !)
 
 convert using a different remote prefix
   $ git init git-repo7

tests/test-manifest.t

@@ -1,5 +1,3 b''
-#require repobundlerepo
-
 Source bundle was generated with the following script:
 
 # hg init
@@ -12,7 +10,13 b' Source bundle was generated with the fol'
 # hg ci -Amb -d'1 0'
 
   $ hg init
-  $ hg -q pull "$TESTDIR/bundles/test-manifest.hg"
+  $ hg unbundle "$TESTDIR/bundles/test-manifest.hg"
+  adding changesets
+  adding manifests
+  adding file changes
+  added 2 changesets with 3 changes to 3 files
+  new changesets b73562a03cfe:5bdc995175ba
+  (run 'hg update' to get a working copy)
 
 The next call is expected to return nothing:
 
@@ -64,9 +68,9 b' The next call is expected to return noth'
   l
 
   $ hg manifest --all
-  a
-  b/a
-  l
+  a (no-reposimplestore !)
+  b/a (no-reposimplestore !)
+  l (no-reposimplestore !)
 
 The next two calls are expected to abort: