Setup: $ cat > eval.py < from __future__ import absolute_import > import filecmp > from mercurial import commands, context, registrar > cmdtable = {} > command = registrar.command(cmdtable) > @command(b'eval', [], 'hg eval CMD') > def eval_(ui, repo, *cmds, **opts): > cmd = " ".join(cmds) > res = str(eval(cmd, globals(), locals())) > ui.warn("%s" % res) > EOF $ echo "[extensions]" >> $HGRCPATH $ echo "eval=`pwd`/eval.py" >> $HGRCPATH Arbitraryfilectx.cmp does not follow symlinks: $ mkdir case1 $ cd case1 $ hg init #if symlink $ printf "A" > real_A $ printf "foo" > A $ printf "foo" > B $ ln -s A sym_A $ hg add . adding A adding B adding real_A adding sym_A $ hg commit -m "base" #else $ hg import -q --bypass - < # HG changeset patch > # User test > # Date 0 0 > base > > diff --git a/A b/A > new file mode 100644 > --- /dev/null > +++ b/A > @@ -0,0 +1,1 @@ > +foo > \ No newline at end of file > diff --git a/B b/B > new file mode 100644 > --- /dev/null > +++ b/B > @@ -0,0 +1,1 @@ > +foo > \ No newline at end of file > diff --git a/real_A b/real_A > new file mode 100644 > --- /dev/null > +++ b/real_A > @@ -0,0 +1,1 @@ > +A > \ No newline at end of file > diff --git a/sym_A b/sym_A > new file mode 120000 > --- /dev/null > +++ b/sym_A > @@ -0,0 +1,1 @@ > +A > \ No newline at end of file > EOF $ hg up -q #endif These files are different and should return True (different): (Note that filecmp.cmp's return semantics are inverted from ours, so we invert for simplicity): $ hg eval "context.arbitraryfilectx('A', repo).cmp(repo[None]['real_A'])" True (no-eol) $ hg eval "not filecmp.cmp('A', 'real_A')" True (no-eol) These files are identical and should return False (same): $ hg eval "context.arbitraryfilectx('A', repo).cmp(repo[None]['A'])" False (no-eol) $ hg eval "context.arbitraryfilectx('A', repo).cmp(repo[None]['B'])" False (no-eol) $ hg eval "not filecmp.cmp('A', 'B')" False (no-eol) This comparison should also return False, since A and sym_A are substantially the same in the eyes of ``filectx.cmp``, which looks at data only. $ hg eval "context.arbitraryfilectx('real_A', repo).cmp(repo[None]['sym_A'])" False (no-eol) A naive use of filecmp on those two would wrongly return True, since it follows the symlink to "A", which has different contents. #if symlink $ hg eval "not filecmp.cmp('real_A', 'sym_A')" True (no-eol) #else $ hg eval "not filecmp.cmp('real_A', 'sym_A')" False (no-eol) #endif