Re: [fossil-users] Partial hash collision
On Tue, Mar 25, 2014 at 11:50 PM, Andy Goth andrew.m.g...@gmail.com wrote: and allows you to search for commits by prefix. IOW the prefix thing is a pure convenience to reduce the amount of stuff to enter. Understood, but this convenience feature feeds back into the database when the user enters a prefix into a commit comment or a ticket or a wiki page. I would assume that a non-unique prefix should resolve to the earlier of the two. That would solve this problem, since older tickets etc. would continue to refer to the same commit/artifact as they did originally. I don't know if this is what actually happens, though. -- ˙uʍop-ǝpısdn sı ɹoʇıuoɯ ɹnoʎ 'sıɥʇ pɐǝɹ uɐɔ noʎ ɟı ___ fossil-users mailing list fossil-users@lists.fossil-scm.org http://lists.fossil-scm.org:8080/cgi-bin/mailman/listinfo/fossil-users
Re: [fossil-users] Partial hash collision
I was wrong. See http://www.fossil-scm.org/index.html/artifact/ebb0 On Wed, Mar 26, 2014 at 9:15 AM, Baruch Burstein bmburst...@gmail.comwrote: On Tue, Mar 25, 2014 at 11:50 PM, Andy Goth andrew.m.g...@gmail.comwrote: and allows you to search for commits by prefix. IOW the prefix thing is a pure convenience to reduce the amount of stuff to enter. Understood, but this convenience feature feeds back into the database when the user enters a prefix into a commit comment or a ticket or a wiki page. I would assume that a non-unique prefix should resolve to the earlier of the two. That would solve this problem, since older tickets etc. would continue to refer to the same commit/artifact as they did originally. I don't know if this is what actually happens, though. -- ˙uʍop-ǝpısdn sı ɹoʇıuoɯ ɹnoʎ 'sıɥʇ pɐǝɹ uɐɔ noʎ ɟı -- ˙uʍop-ǝpısdn sı ɹoʇıuoɯ ɹnoʎ 'sıɥʇ pɐǝɹ uɐɔ noʎ ɟı ___ fossil-users mailing list fossil-users@lists.fossil-scm.org http://lists.fossil-scm.org:8080/cgi-bin/mailman/listinfo/fossil-users
Re: [fossil-users] Partial hash collision
On Tue, Mar 25, 2014 at 5:50 PM, Andy Goth andrew.m.g...@gmail.com wrote: On 3/25/2014 4:40 PM, Andreas Kupries wrote: On Tue, Mar 25, 2014 at 2:28 PM, Andy Goth andrew.m.g...@gmail.com wrote: Fossil uses unique prefixes of checksums as identifiers. No, it does not. Fossil stores full identifiers I was referring only to the display. Full identifiers are usually shown only in detail pages and the actual manifests. My original idea was to show the first 10 characters of the hash in all cases and if the first 10 characters are ambiguous, show additional characters as necessary to make the hash unambiguous. But, as the longest collision I've yet seen is only 4 characters, I never have gotten around to modifying the display logic. In order to get a 10-character collision on the SHA1 hash to two check-ins, you'd need a repository with about a million check-ins (or else you'd need to be very unlucky). The TCL project has 17241 check-ins over 16 years. SQLite has 12841 check-ins in 13.8 years. Fossil has 6823 check-ins in 6.7 years. Do you see the trend? The first collision is hundreds of years away. But, yes, it would be good to go ahead and fix this. -- D. Richard Hipp d...@sqlite.org ___ fossil-users mailing list fossil-users@lists.fossil-scm.org http://lists.fossil-scm.org:8080/cgi-bin/mailman/listinfo/fossil-users
Re: [fossil-users] Partial hash collision
2014-03-26 11:42 GMT+01:00 Baruch Burstein bmburst...@gmail.com: On Wed, Mar 26, 2014 at 12:30 PM, Richard Hipp d...@sqlite.org wrote: But, as the longest collision I've yet seen is only 4 characters, I never have gotten around to modifying the display logic. Just for the record: Fossil itself has a 7 character collision. I didn't check the netbsd repositories. http://fossil-scm.org/index.html/info/a16236e70dafc57f564b20f35670afad02a8fc7a A fossil rebuild is necessary for this to appear in the ticket hyperlinks as well. Regards, Jan Nijtmans ___ fossil-users mailing list fossil-users@lists.fossil-scm.org http://lists.fossil-scm.org:8080/cgi-bin/mailman/listinfo/fossil-users
Re: [fossil-users] Partial hash collision
Out of curiosity, in the tcl repository I found 2 8-long collisions. I don't have anything bigger to test. This is what I used: select substr(uuid, 1, 8) a, count(*) b from blob group by a having b1 order by b; On Wed, Mar 26, 2014 at 1:01 PM, Jan Nijtmans jan.nijtm...@gmail.comwrote: 2014-03-26 11:42 GMT+01:00 Baruch Burstein bmburst...@gmail.com: On Wed, Mar 26, 2014 at 12:30 PM, Richard Hipp d...@sqlite.org wrote: But, as the longest collision I've yet seen is only 4 characters, I never have gotten around to modifying the display logic. Just for the record: Fossil itself has a 7 character collision. I didn't check the netbsd repositories. http://fossil-scm.org/index.html/info/a16236e70dafc57f564b20f35670afad02a8fc7a A fossil rebuild is necessary for this to appear in the ticket hyperlinks as well. Regards, Jan Nijtmans ___ fossil-users mailing list fossil-users@lists.fossil-scm.org http://lists.fossil-scm.org:8080/cgi-bin/mailman/listinfo/fossil-users -- ˙uʍop-ǝpısdn sı ɹoʇıuoɯ ɹnoʎ 'sıɥʇ pɐǝɹ uɐɔ noʎ ɟı ___ fossil-users mailing list fossil-users@lists.fossil-scm.org http://lists.fossil-scm.org:8080/cgi-bin/mailman/listinfo/fossil-users
Re: [fossil-users] Partial hash collision
On Wed, Mar 26, 2014 at 01:36:46PM +0200, Baruch Burstein wrote: Out of curiosity, in the tcl repository I found 2 8-long collisions. I don't have anything bigger to test. This is what I used: select substr(uuid, 1, 8) a, count(*) b from blob group by a having b1 order by b; By that test, I see 467 collission for src.fossil for 8 characters and 4 collissions for 10 characters. For pkgsrc.fossil it is 142 collisions for 8 characters and none for 10 characters. Joerg ___ fossil-users mailing list fossil-users@lists.fossil-scm.org http://lists.fossil-scm.org:8080/cgi-bin/mailman/listinfo/fossil-users
Re: [fossil-users] Partial hash collision
On Wed, Mar 26, 2014 at 1:14 PM, Joerg Sonnenberger jo...@britannica.bec.de wrote: By that test, I see 467 collission for src.fossil for 8 characters and 4 collissions for 10 characters. For pkgsrc.fossil it is 142 collisions for 8 characters and none for 10 characters. Last summer i remember running some numbers on this in the tcl repo and IIRC the biggest collision was 10 or 11. 12 seemed to be the magic point at which all collisions disappear (IIRC). -- - stephan beal http://wanderinghorse.net/home/stephan/ http://gplus.to/sgbeal Freedom is sloppy. But since tyranny's the only guaranteed byproduct of those who insist on a perfect world, freedom will have to do. -- Bigby Wolf ___ fossil-users mailing list fossil-users@lists.fossil-scm.org http://lists.fossil-scm.org:8080/cgi-bin/mailman/listinfo/fossil-users
Re: [fossil-users] Partial hash collision
Hi Folks:Can some one please guide me how to configure fossil web server on 80 port. I want to change it from 8080 to 80. on a ubuntu box. -Abhinas Date: Wed, 26 Mar 2014 14:14:25 +0100 From: sgb...@googlemail.com To: fossil-users@lists.fossil-scm.org Subject: Re: [fossil-users] Partial hash collision On Wed, Mar 26, 2014 at 1:22 PM, Stephan Beal sgb...@googlemail.com wrote: Last summer i remember running some numbers on this in the tcl repo and IIRC the biggest collision was 10 or 11. 12 seemed to be the magic point at which all collisions disappear (IIRC). It seems that in fossil the highest collision in fossil is 8 bytes long: sqlite select substr(uuid,0,8) as short, count(*) from blob group by short having count(short)1; b652b90|2sqlite select uuid from blob where uuid glob 'b652b90*'; b652b900e940c3bb5cbbfb2b0c4a98cb5edb1c90 # a ticket re. RSS feedb652b9088b0d9e9cc8c2fb4c153443d72429d7c9 # some old/replaced C file sqlite select substr(uuid,0,9) as short, count(*) from blob group by short having count(short)1;sqlite select substr(uuid,0,10) as short, count(*) from blob group by short having count(short)1; sqlite select substr(uuid,0,11) as short, count(*) from blob group by short having count(short)1; collisions start to become common at 7 bytes: sqlite select substr(uuid,0,7) as short, count(*) from blob group by short having count(short)1; 0830c3|26fdf52|28d712d|2904ab4|2927257|2940431|2b652b9|2ba837f|2bdbf14|2be32eb|2c1b1ba|2c8735d|2 d07537|2d43165|2e980ba|2ef17fb|2f94f7e|2 -- - stephan beal http://wanderinghorse.net/home/stephan/ http://gplus.to/sgbealFreedom is sloppy. But since tyranny's the only guaranteed byproduct of those who insist on a perfect world, freedom will have to do. -- Bigby Wolf ___ fossil-users mailing list fossil-users@lists.fossil-scm.org http://lists.fossil-scm.org:8080/cgi-bin/mailman/listinfo/fossil-users ___ fossil-users mailing list fossil-users@lists.fossil-scm.org http://lists.fossil-scm.org:8080/cgi-bin/mailman/listinfo/fossil-users
Re: [fossil-users] Partial hash collision
@Mallik. If you are using fossil server, start it with -P 80 or --port 8080. JR On Wed, Mar 26, 2014 at 10:57 AM, Mallik Abhinas fiftysix...@outlook.comwrote: Hi Folks: Can some one please guide me how to configure fossil web server on 80 port. I want to change it from 8080 to 80. on a ubuntu box. -Abhinas -- Date: Wed, 26 Mar 2014 14:14:25 +0100 From: sgb...@googlemail.com To: fossil-users@lists.fossil-scm.org Subject: Re: [fossil-users] Partial hash collision On Wed, Mar 26, 2014 at 1:22 PM, Stephan Beal sgb...@googlemail.comwrote: Last summer i remember running some numbers on this in the tcl repo and IIRC the biggest collision was 10 or 11. 12 seemed to be the magic point at which all collisions disappear (IIRC). It seems that in fossil the highest collision in fossil is 8 bytes long: sqlite select substr(uuid,0,8) as short, count(*) from blob group by short having count(short)1; b652b90|2 sqlite select uuid from blob where uuid glob 'b652b90*'; b652b900e940c3bb5cbbfb2b0c4a98cb5edb1c90 # a ticket re. RSS feed b652b9088b0d9e9cc8c2fb4c153443d72429d7c9 # some old/replaced C file sqlite select substr(uuid,0,9) as short, count(*) from blob group by short having count(short)1; sqlite select substr(uuid,0,10) as short, count(*) from blob group by short having count(short)1; sqlite select substr(uuid,0,11) as short, count(*) from blob group by short having count(short)1; collisions start to become common at 7 bytes: sqlite select substr(uuid,0,7) as short, count(*) from blob group by short having count(short)1; 0830c3|2 6fdf52|2 8d712d|2 904ab4|2 927257|2 940431|2 b652b9|2 ba837f|2 bdbf14|2 be32eb|2 c1b1ba|2 c8735d|2 d07537|2 d43165|2 e980ba|2 ef17fb|2 f94f7e|2 -- - stephan beal http://wanderinghorse.net/home/stephan/ http://gplus.to/sgbeal Freedom is sloppy. But since tyranny's the only guaranteed byproduct of those who insist on a perfect world, freedom will have to do. -- Bigby Wolf ___ fossil-users mailing list fossil-users@lists.fossil-scm.org http://lists.fossil-scm.org:8080/cgi-bin/mailman/listinfo/fossil-users ___ fossil-users mailing list fossil-users@lists.fossil-scm.org http://lists.fossil-scm.org:8080/cgi-bin/mailman/listinfo/fossil-users ___ fossil-users mailing list fossil-users@lists.fossil-scm.org http://lists.fossil-scm.org:8080/cgi-bin/mailman/listinfo/fossil-users
Re: [fossil-users] Partial hash collision
On Wed, Mar 26, 2014 at 5:03 PM, Mallik Abhinas fiftysix...@outlook.comwrote: @ JR: Could you please guide me where do I change it ? You pass the parameters JR mentioned to fossil, like this: fossil server --port 8080 then visit http://localhost:8080 with your browser. -- - stephan beal http://wanderinghorse.net/home/stephan/ http://gplus.to/sgbeal Freedom is sloppy. But since tyranny's the only guaranteed byproduct of those who insist on a perfect world, freedom will have to do. -- Bigby Wolf ___ fossil-users mailing list fossil-users@lists.fossil-scm.org http://lists.fossil-scm.org:8080/cgi-bin/mailman/listinfo/fossil-users
Re: [fossil-users] Partial hash collision
@Stephen: Do I have to be a root to run this command in terminal ? And I want it to be changed to 80, I want my website to run in 80 port not on 8080. -Mallik Date: Wed, 26 Mar 2014 17:14:20 +0100 From: sgb...@googlemail.com To: fossil-users@lists.fossil-scm.org Subject: Re: [fossil-users] Partial hash collision On Wed, Mar 26, 2014 at 5:03 PM, Mallik Abhinas fiftysix...@outlook.com wrote: @ JR: Could you please guide me where do I change it ? You pass the parameters JR mentioned to fossil, like this: fossil server --port 8080 then visit http://localhost:8080 with your browser. -- - stephan beal http://wanderinghorse.net/home/stephan/ http://gplus.to/sgbealFreedom is sloppy. But since tyranny's the only guaranteed byproduct of those who insist on a perfect world, freedom will have to do. -- Bigby Wolf ___ fossil-users mailing list fossil-users@lists.fossil-scm.org http://lists.fossil-scm.org:8080/cgi-bin/mailman/listinfo/fossil-users ___ fossil-users mailing list fossil-users@lists.fossil-scm.org http://lists.fossil-scm.org:8080/cgi-bin/mailman/listinfo/fossil-users
[fossil-users] Partial hash collision
Fossil uses unique prefixes of checksums as identifiers. What does it do when a previously-unique prefix becomes ambiguous due to a new commit? Also, what happens when an existing comment (or ticket or wiki page or whatever) references a no-longer-unique prefix? Fossil can't rewrite the old manifest without changing every checksum forward, so its only hope is to change the display, but that leads to more problems. It's quite likely this has already been discussed and resolved, but I haven't been able to track down any emails or documentation on the matter. I wish I could give you a test case, but the SHA1 function is thankfully difficult to invert, even for prefixes. :^) -- Andy Goth | andrew.m.goth/at/gmail/dot/com ___ fossil-users mailing list fossil-users@lists.fossil-scm.org http://lists.fossil-scm.org:8080/cgi-bin/mailman/listinfo/fossil-users
Re: [fossil-users] Partial hash collision
On 3/25/2014 4:40 PM, Andreas Kupries wrote: On Tue, Mar 25, 2014 at 2:28 PM, Andy Goth andrew.m.g...@gmail.com wrote: Fossil uses unique prefixes of checksums as identifiers. No, it does not. Fossil stores full identifiers I was referring only to the display. Full identifiers are usually shown only in detail pages and the actual manifests. and allows you to search for commits by prefix. IOW the prefix thing is a pure convenience to reduce the amount of stuff to enter. Understood, but this convenience feature feeds back into the database when the user enters a prefix into a commit comment or a ticket or a wiki page. -- Andy Goth | andrew.m.goth/at/gmail/dot/com ___ fossil-users mailing list fossil-users@lists.fossil-scm.org http://lists.fossil-scm.org:8080/cgi-bin/mailman/listinfo/fossil-users
