Mercurial > hg
view mercurial/dummycert.pem @ 29322:66dbdd3cc2b9 stable
bdiff: extend matches across popular lines
For very large diffs that have large numbers of identical lines (JSON
dumps) that also have large blocks of identical text, bdiff could become
confused about which block matches which because it can only match
very limited regions. The result is very large diffs for small sets of edits.
The earlier recursion rebalancing fix made this behavior more frequent because
it's now more prone to match block 1 to block 2. One frequent user of
large JSON files reported being unable to pass the resulting diffs
through their code review system.
Prior to this change, bdiff would calculate the length of a match at
(i, j) as 1 + length found at (i-1, j-1). With large number of popular
(ignored) lines, this often meant matches couldn't be extended
backwards at all and thus all matching regions were very small.
Disabling the popularity threshold is not an option because it brings
back quadratic behavior.
Instead, we extend a match backwards until we either found a previously
discovered match or we find a mismatching line. This thus successfully
bridges over any popular lines inside and before a matching region.
The larger regions then significant reduce the probability of confusion.
author | Matt Mackall <mpm@selenic.com> |
---|---|
date | Thu, 02 Jun 2016 17:09:06 -0500 |
parents | d7f7f1860f00 |
children |
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A dummy certificate that will make OS X 10.6+ Python use the system CA certificate store: -----BEGIN CERTIFICATE----- MIIBIzCBzgIJANjmj39sb3FmMA0GCSqGSIb3DQEBBQUAMBkxFzAVBgNVBAMTDmhn LmV4YW1wbGUuY29tMB4XDTE0MDgzMDA4NDU1OVoXDTE0MDgyOTA4NDU1OVowGTEX MBUGA1UEAxMOaGcuZXhhbXBsZS5jb20wXDANBgkqhkiG9w0BAQEFAANLADBIAkEA mh/ZySGlcq0ALNLmA1gZqt61HruywPrRk6WyrLJRgt+X7OP9FFlEfl2tzHfzqvmK CtSQoPINWOdAJMekBYFgKQIDAQABMA0GCSqGSIb3DQEBBQUAA0EAF9h49LkSqJ6a IlpogZuUHtihXeKZBsiktVIDlDccYsNy0RSh9XxUfhk+XMLw8jBlYvcltSXdJ7We aKdQRekuMQ== -----END CERTIFICATE----- This certificate was generated to be syntactically valid but never be usable; it expired before it became valid. Created as: $ cat > cn.conf << EOT > [req] > distinguished_name = req_distinguished_name > [req_distinguished_name] > commonName = Common Name > commonName_default = no.example.com > EOT $ openssl req -nodes -new -x509 -keyout /dev/null \ > -out dummycert.pem -days -1 -config cn.conf -subj '/CN=hg.example.com' To verify the content of this certificate: $ openssl x509 -in dummycert.pem -noout -text Certificate: Data: Version: 1 (0x0) Serial Number: 15629337334278746470 (0xd8e68f7f6c6f7166) Signature Algorithm: sha1WithRSAEncryption Issuer: CN=hg.example.com Validity Not Before: Aug 30 08:45:59 2014 GMT Not After : Aug 29 08:45:59 2014 GMT Subject: CN=hg.example.com Subject Public Key Info: Public Key Algorithm: rsaEncryption Public-Key: (512 bit) Modulus: 00:9a:1f:d9:c9:21:a5:72:ad:00:2c:d2:e6:03:58: 19:aa:de:b5:1e:bb:b2:c0:fa:d1:93:a5:b2:ac:b2: 51:82:df:97:ec:e3:fd:14:59:44:7e:5d:ad:cc:77: f3:aa:f9:8a:0a:d4:90:a0:f2:0d:58:e7:40:24:c7: a4:05:81:60:29 Exponent: 65537 (0x10001) Signature Algorithm: sha1WithRSAEncryption 17:d8:78:f4:b9:12:a8:9e:9a:22:5a:68:81:9b:94:1e:d8:a1: 5d:e2:99:06:c8:a4:b5:52:03:94:37:1c:62:c3:72:d1:14:a1: f5:7c:54:7e:19:3e:5c:c2:f0:f2:30:65:62:f7:25:b5:25:dd: 27:b5:9e:68:a7:50:45:e9:2e:31