$ hg init t
$ cd t
$ echo foo > a
$ hg add a
$ hg commit -m "1"
$ hg verify
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
1 files, 1 changesets, 1 total revisions
$ chmod -r .hg/store/data/a.i
$ hg verify || echo %%% verify failed
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
abort: Permission denied: .*
%%% verify failed
$ chmod +r .hg/store/data/a.i
$ hg verify || echo %%% verify failed
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
1 files, 1 changesets, 1 total revisions
$ chmod -w .hg/store/data/a.i
$ echo barber > a
$ hg commit -m "2" || echo %%% commit failed
trouble committing a!
abort: Permission denied: .*
%%% commit failed
$ chmod -w .
$ hg diff --nodates
diff -r 2a18120dc1c9 a
--- a/a
+++ b/a
@@ -1,1 +1,1 @@
-foo
+barber
$ chmod +w .
$ chmod +w .hg/store/data/a.i
$ mkdir dir
$ touch dir/a
$ hg status
M a
? dir/a
$ chmod -rx dir
$ hg status
dir: Permission denied
M a
Reenable perm to allow deletion:
$ chmod +rx dir