debugdeltachain: avoid division by zero when a chain is empty
The two ratios chainratio and extraratio are computed using dividers
that may be zero when the file is empty.
As the denominators are integers, the limit of the ratio "just before zero" is
the numerator value itself.
If the numerator itself is zero, the ratio value is still meaningful: in both
cases, a "good" value is a low ratio, and a size of zero is the optimal case.
$ . $TESTDIR/wireprotohelpers.sh
$ hg init server
$ enablehttpv2 server
$ cd server
$ hg debugdrawdag << EOF
> H I J
> | | |
> E F G
> | |/
> C D
> |/
> B
> |
> A
> EOF
$ hg phase --force --secret J
$ hg phase --public E
$ hg log -r 'E + H + I + G + J' -T '{rev}:{node} {desc} {phase}\n'
4:78d2dca436b2f5b188ac267e29b81e07266d38fc E public
7:ae492e36b0c8339ffaf328d00b85b4525de1165e H draft
8:1d6f6b91d44aaba6d5e580bc30a9948530dbe00b I draft
6:29446d2dc5419c5f97447a8bc062e4cc328bf241 G draft
9:dec04b246d7cbb670c6689806c05ad17c835284e J secret
$ hg serve -p $HGPORT -d --pid-file hg.pid -E error.log
$ cat hg.pid > $DAEMON_PIDS
All non-secret heads returned by default
$ sendhttpv2peer << EOF
> command heads
> EOF
creating http peer for wire protocol version 2
sending heads command
s> POST /api/exp-http-v2-0001/ro/heads HTTP/1.1\r\n
s> Accept-Encoding: identity\r\n
s> accept: application/mercurial-exp-framing-0005\r\n
s> content-type: application/mercurial-exp-framing-0005\r\n
s> content-length: 20\r\n
s> host: $LOCALIP:$HGPORT\r\n (glob)
s> user-agent: Mercurial debugwireproto\r\n
s> \r\n
s> \x0c\x00\x00\x01\x00\x01\x01\x11\xa1DnameEheads
s> makefile('rb', None)
s> HTTP/1.1 200 OK\r\n
s> Server: testing stub value\r\n
s> Date: $HTTP_DATE$\r\n
s> Content-Type: application/mercurial-exp-framing-0005\r\n
s> Transfer-Encoding: chunked\r\n
s> \r\n
s> 53\r\n
s> K\x00\x00\x01\x00\x02\x012
s> \xa1FstatusBok\x83T\x1dok\x91\xd4J\xab\xa6\xd5\xe5\x80\xbc0\xa9\x94\x850\xdb\xe0\x0bT\xaeI.6\xb0\xc83\x9f\xfa\xf3(\xd0\x0b\x85\xb4R]\xe1\x16^T)Dm-\xc5A\x9c_\x97Dz\x8b\xc0b\xe4\xcc2\x8b\xf2A
s> \r\n
received frame(size=75; request=1; stream=2; streamflags=stream-begin; type=command-response; flags=eos)
s> 0\r\n
s> \r\n
response: [b'\x1dok\x91\xd4J\xab\xa6\xd5\xe5\x80\xbc0\xa9\x94\x850\xdb\xe0\x0b', b'\xaeI.6\xb0\xc83\x9f\xfa\xf3(\xd0\x0b\x85\xb4R]\xe1\x16^', b')Dm-\xc5A\x9c_\x97Dz\x8b\xc0b\xe4\xcc2\x8b\xf2A']
Requesting just the public heads works
$ sendhttpv2peer << EOF
> command heads
> publiconly 1
> EOF
creating http peer for wire protocol version 2
sending heads command
s> POST /api/exp-http-v2-0001/ro/heads HTTP/1.1\r\n
s> Accept-Encoding: identity\r\n
s> accept: application/mercurial-exp-framing-0005\r\n
s> content-type: application/mercurial-exp-framing-0005\r\n
s> content-length: 39\r\n
s> host: $LOCALIP:$HGPORT\r\n (glob)
s> user-agent: Mercurial debugwireproto\r\n
s> \r\n
s> \x1f\x00\x00\x01\x00\x01\x01\x11\xa2Dargs\xa1JpubliconlyA1DnameEheads
s> makefile('rb', None)
s> HTTP/1.1 200 OK\r\n
s> Server: testing stub value\r\n
s> Date: $HTTP_DATE$\r\n
s> Content-Type: application/mercurial-exp-framing-0005\r\n
s> Transfer-Encoding: chunked\r\n
s> \r\n
s> 29\r\n
s> !\x00\x00\x01\x00\x02\x012
s> \xa1FstatusBok\x81Tx\xd2\xdc\xa46\xb2\xf5\xb1\x88\xac&~)\xb8\x1e\x07&m8\xfc
s> \r\n
received frame(size=33; request=1; stream=2; streamflags=stream-begin; type=command-response; flags=eos)
s> 0\r\n
s> \r\n
response: [b'x\xd2\xdc\xa46\xb2\xf5\xb1\x88\xac&~)\xb8\x1e\x07&m8\xfc']
$ cat error.log