diff -r 20d0e59be79b -r d98ec36be808 tests/test-convert-identity.t
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tests/test-convert-identity.t	Sat Jul 13 23:45:32 2019 -0400
@@ -0,0 +1,40 @@
+Testing that convert.hg.preserve-hash=true can be used to make hg
+convert from hg repo to hg repo preserve hashes, even if the
+computation of the files list in commits change slightly between hg
+versions.
+
+  $ cat <<'EOF' >> "$HGRCPATH"
+  > [extensions]
+  > convert =
+  > EOF
+  $ cat <<'EOF' > changefileslist.py
+  > from mercurial import (changelog, extensions)
+  > def wrap(orig, clog, manifest, files, *args, **kwargs):
+  >   return orig(clog, manifest, ["a"], *args, **kwargs)
+  > def extsetup(ui):
+  >   extensions.wrapfunction(changelog.changelog, 'add', wrap)
+  > EOF
+
+  $ hg init repo
+  $ cd repo
+  $ echo a > a; hg commit -qAm a
+  $ echo b > a; hg commit -qAm b
+  $ hg up -qr 0; echo c > c; hg commit -qAm c
+  $ hg merge -qr 1
+  $ hg commit -m_ --config extensions.x=../changefileslist.py
+  $ hg log -r . -T '{node|short} {files|json}\n'
+  c085bbe93d59 ["a"]
+
+Now that we have a commit with a files list that's not what the
+current hg version would create, check that convert either fixes it or
+keeps it depending on config:
+
+  $ hg convert -q . ../convert
+  $ hg --cwd ../convert log -r tip -T '{node|short} {files|json}\n'
+  b7c4d4bbacd3 []
+  $ rm -rf ../convert
+
+  $ hg convert -q . ../convert --config convert.hg.preserve-hash=true
+  $ hg --cwd ../convert log -r tip -T '{node|short} {files|json}\n'
+  c085bbe93d59 ["a"]
+  $ rm -rf ../convert