patch: support diff data loss detection and upgrade
In worst case, generating diff in upgrade mode can be two times more expensive
than generating it in git mode directly: we may have to regenerate the whole
diff again whenever a git feature is detected. Also, the first diff attempt is
completely buffered instead of being streamed. That said, even without having
profiled it yet, I am convinced we can fast-path the upgrade mode if necessary
were it to be used in regular diff commands, and not only in mq where avoiding
data loss is worth the price.
#!/bin/sh
hg init
echo % should fail
hg add .hg/00changelog.i
mkdir a
echo a > a/a
hg ci -Ama
ln -s a b
echo b > a/b
echo % should fail
hg add b/b
echo % should succeed
hg add b
echo % should still fail - maybe
hg add b/b
echo % unbundle tampered bundle
hg init target
cd target
hg unbundle $TESTDIR/tampered.hg
echo % attack .hg/test
hg manifest -r0
hg update -Cr0
echo % attack foo/.hg/test
hg manifest -r1
hg update -Cr1
echo % attack back/test where back symlinks to ..
hg manifest -r2
hg update -Cr2
echo % attack ../test
hg manifest -r3
hg update -Cr3
echo % attack /tmp/test
hg manifest -r4
hg update -Cr4 2>&1 | sed -e "s|/.*/test-audit-path|[HGTMP]/test-audit-path|"
exit 0