Mercurial > hg
view tests/test-http-api.t @ 46607:e9901d01d135
revlog: add a mechanism to verify expected file position before appending
If someone uses `hg debuglocks`, or some non-hg process writes to the .hg
directory without respecting the locks, or if the repo's on a networked
filesystem, it's possible for the revlog code to write out corrupted data.
The form of this corruption can vary depending on what data was written and how
that happened. We are in the "networked filesystem" case (though I've had users
also do this to themselves with the "`hg debuglocks`" scenario), and most often
see this with the changelog. What ends up happening is we produce two items
(let's call them rev1 and rev2) in the .i file that have the same linkrev,
baserev, and offset into the .d file, while the data in the .d file is appended
properly. rev2's compressed_size is accurate for rev2, but when we go to
decompress the data in the .d file, we use the offset that's recorded in the
index file, which is the same as rev1, and attempt to decompress
rev2.compressed_size bytes of rev1's data. This usually does not succeed. :)
When using inline data, this also fails, though I haven't investigated why too
closely. This shows up as a "patch decode" error. I believe what's happening
there is that we're basically ignoring the offset field, getting the data
properly, but since baserev != rev, it thinks this is a delta based on rev
(instead of a full text) and can't actually apply it as such.
For now, I'm going to make this an optional component and default it to entirely
off. I may increase the default severity of this in the future, once I've
enabled it for my users and we gain more experience with it. Luckily, most of my
users have a versioned filesystem and can roll back to before the corruption has
been written, it's just a hassle to do so and not everyone knows how (so it's a
support burden). Users on other filesystems will not have that luxury, and this
can cause them to have a corrupted repository that they are unlikely to know how
to resolve, and they'll see this as a data-loss event. Refusing to create the
corruption is a much better user experience.
This mechanism is not perfect. There may be false-negatives (racy writes that
are not detected). There should not be any false-positives (non-racy writes that
are detected as such). This is not a mechanism that makes putting a repo on a
networked filesystem "safe" or "supported", just *less* likely to cause
corruption.
Differential Revision: https://phab.mercurial-scm.org/D9952
author | Kyle Lippincott <spectral@google.com> |
---|---|
date | Wed, 03 Feb 2021 16:33:10 -0800 |
parents | 2f7408b7d247 |
children |
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#require no-chg $ send() { > hg --verbose debugwireproto --peer raw http://$LOCALIP:$HGPORT/ > } $ hg init server $ hg -R server serve -p $HGPORT -d --pid-file hg.pid $ cat hg.pid > $DAEMON_PIDS Request to /api fails unless web.apiserver is enabled $ get-with-headers.py $LOCALIP:$HGPORT api 400 no such method: api <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en-US"> <head> <link rel="icon" href="/static/hgicon.png" type="image/png" /> <meta name="robots" content="index, nofollow" /> <link rel="stylesheet" href="/static/style-paper.css" type="text/css" /> <script type="text/javascript" src="/static/mercurial.js"></script> <title>$TESTTMP/server: error</title> </head> <body> <div class="container"> <div class="menu"> <div class="logo"> <a href="https://mercurial-scm.org/"> <img src="/static/hglogo.png" width=75 height=90 border=0 alt="mercurial" /></a> </div> <ul> <li><a href="/shortlog">log</a></li> <li><a href="/graph">graph</a></li> <li><a href="/tags">tags</a></li> <li><a href="/bookmarks">bookmarks</a></li> <li><a href="/branches">branches</a></li> </ul> <ul> <li><a href="/help">help</a></li> </ul> </div> <div class="main"> <h2 class="breadcrumb"><a href="/">Mercurial</a> </h2> <h3>error</h3> <form class="search" action="/log"> <p><input name="rev" id="search1" type="text" size="30" value="" /></p> <div id="hint">Find changesets by keywords (author, files, the commit message), revision number or hash, or <a href="/help/revsets">revset expression</a>.</div> </form> <div class="description"> <p> An error occurred while processing your request: </p> <p> no such method: api </p> </div> </div> </div> </body> </html> [1] $ get-with-headers.py $LOCALIP:$HGPORT api/ 400 no such method: api <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en-US"> <head> <link rel="icon" href="/static/hgicon.png" type="image/png" /> <meta name="robots" content="index, nofollow" /> <link rel="stylesheet" href="/static/style-paper.css" type="text/css" /> <script type="text/javascript" src="/static/mercurial.js"></script> <title>$TESTTMP/server: error</title> </head> <body> <div class="container"> <div class="menu"> <div class="logo"> <a href="https://mercurial-scm.org/"> <img src="/static/hglogo.png" width=75 height=90 border=0 alt="mercurial" /></a> </div> <ul> <li><a href="/shortlog">log</a></li> <li><a href="/graph">graph</a></li> <li><a href="/tags">tags</a></li> <li><a href="/bookmarks">bookmarks</a></li> <li><a href="/branches">branches</a></li> </ul> <ul> <li><a href="/help">help</a></li> </ul> </div> <div class="main"> <h2 class="breadcrumb"><a href="/">Mercurial</a> </h2> <h3>error</h3> <form class="search" action="/log"> <p><input name="rev" id="search1" type="text" size="30" value="" /></p> <div id="hint">Find changesets by keywords (author, files, the commit message), revision number or hash, or <a href="/help/revsets">revset expression</a>.</div> </form> <div class="description"> <p> An error occurred while processing your request: </p> <p> no such method: api </p> </div> </div> </div> </body> </html> [1] Restart server with support for API server $ killdaemons.py $ cat > server/.hg/hgrc << EOF > [experimental] > web.apiserver = true > EOF $ hg -R server serve -p $HGPORT -d --pid-file hg.pid $ cat hg.pid > $DAEMON_PIDS /api lists available APIs (empty since none are available by default) $ send << EOF > httprequest GET api > user-agent: test > EOF using raw connection to peer s> setsockopt(6, 1, 1) -> None (?) s> GET /api HTTP/1.1\r\n s> Accept-Encoding: identity\r\n s> user-agent: test\r\n s> host: $LOCALIP:$HGPORT\r\n (glob) s> \r\n 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: text/plain\r\n s> Content-Length: 100\r\n s> \r\n s> APIs can be accessed at /api/<name>, where <name> can be one of the following:\n s> \n s> (no available APIs)\n $ send << EOF > httprequest GET api/ > user-agent: test > EOF using raw connection to peer s> setsockopt(6, 1, 1) -> None (?) s> GET /api/ HTTP/1.1\r\n s> Accept-Encoding: identity\r\n s> user-agent: test\r\n s> host: $LOCALIP:$HGPORT\r\n (glob) s> \r\n 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: text/plain\r\n s> Content-Length: 100\r\n s> \r\n s> APIs can be accessed at /api/<name>, where <name> can be one of the following:\n s> \n s> (no available APIs)\n Accessing an unknown API yields a 404 $ send << EOF > httprequest GET api/unknown > user-agent: test > EOF using raw connection to peer s> setsockopt(6, 1, 1) -> None (?) s> GET /api/unknown HTTP/1.1\r\n s> Accept-Encoding: identity\r\n s> user-agent: test\r\n s> host: $LOCALIP:$HGPORT\r\n (glob) s> \r\n s> makefile('rb', None) s> HTTP/1.1 404 Not Found\r\n s> Server: testing stub value\r\n s> Date: $HTTP_DATE$\r\n s> Content-Type: text/plain\r\n s> Content-Length: 33\r\n s> \r\n s> Unknown API: unknown\n s> Known APIs: Accessing a known but not enabled API yields a different error $ send << EOF > httprequest GET api/exp-http-v2-0003 > user-agent: test > EOF using raw connection to peer s> setsockopt(6, 1, 1) -> None (?) s> GET /api/exp-http-v2-0003 HTTP/1.1\r\n s> Accept-Encoding: identity\r\n s> user-agent: test\r\n s> host: $LOCALIP:$HGPORT\r\n (glob) s> \r\n s> makefile('rb', None) s> HTTP/1.1 404 Not Found\r\n s> Server: testing stub value\r\n s> Date: $HTTP_DATE$\r\n s> Content-Type: text/plain\r\n s> Content-Length: 33\r\n s> \r\n s> API exp-http-v2-0003 not enabled\n Restart server with support for HTTP v2 API $ killdaemons.py $ cat > server/.hg/hgrc << EOF > [experimental] > web.apiserver = true > web.api.http-v2 = true > EOF $ hg -R server serve -p $HGPORT -d --pid-file hg.pid $ cat hg.pid > $DAEMON_PIDS /api lists the HTTP v2 protocol as available $ send << EOF > httprequest GET api > user-agent: test > EOF using raw connection to peer s> setsockopt(6, 1, 1) -> None (?) s> GET /api HTTP/1.1\r\n s> Accept-Encoding: identity\r\n s> user-agent: test\r\n s> host: $LOCALIP:$HGPORT\r\n (glob) s> \r\n 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: text/plain\r\n s> Content-Length: 96\r\n s> \r\n s> APIs can be accessed at /api/<name>, where <name> can be one of the following:\n s> \n s> exp-http-v2-0003 $ send << EOF > httprequest GET api/ > user-agent: test > EOF using raw connection to peer s> setsockopt(6, 1, 1) -> None (?) s> GET /api/ HTTP/1.1\r\n s> Accept-Encoding: identity\r\n s> user-agent: test\r\n s> host: $LOCALIP:$HGPORT\r\n (glob) s> \r\n 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: text/plain\r\n s> Content-Length: 96\r\n s> \r\n s> APIs can be accessed at /api/<name>, where <name> can be one of the following:\n s> \n s> exp-http-v2-0003