demandimport: delay loading for "from a import b" with absolute_import
Before this patch, "from a import b" doesn't delay loading module "b",
if absolute_import is enabled, even though "from . import b" does.
For example:
- it is assumed that extension X has "from P import M" for module M
under package P with absolute_import feature
- if importing module M is already delayed before loading extension
X, loading module M in extension X is delayed until actually
referring
util, cmdutil, scmutil or so of Mercurial itself should be
imported by "from . import M" style before loading extension X
- otherwise, module M is loaded immediately at loading extension X,
even if extension X itself isn't used at that "hg" command invocation
Some minor modules (e.g. filemerge or so) of Mercurial itself
aren't imported by "from . import M" style before loading
extension X. And of course, external libraries aren't, too.
This might cause startup performance problem of hg command, because
many bundled extensions already enable absolute_import feature.
To delay loading module for "from a import b" with absolute_import
feature, this patch does below in "from a (or .a) import b" with
absolute_import case:
1. import root module of "name" by system built-in __import__
(referred as _origimport)
2. recurse down the module chain for hierarchical "name"
This logic can be shared with non absolute_import
case. Therefore, this patch also centralizes it into chainmodules().
3. and fall through to process elements in "fromlist" for the leaf
module of "name"
Processing elements in "fromlist" is executed in the code path
after "if _pypy: .... else: ..." clause. Therefore, this patch
replaces "if _pypy:" with "elif _pypy:" to share it.
At 4f1144c3c72b introducing original "work around" for "from a import
b" case, elements in "fromlist" were imported with "level=level". But
"level" might be grater than 1 (e.g. level=2 in "from .. import b"
case) at demandimport() invocation, and importing direct sub-module in
"fromlist" with level grater than 1 causes unexpected result.
IMHO, this seems main reason of "errors for unknown reason" described
in 4f1144c3c72b, and we don't have to worry about it, because this
issue was already fixed by 78d05778907b.
This is reason why this patch removes "errors for unknown reasons"
comment.
#require serve
Test chains of near empty directories, terminating 3 different ways:
- a1: file at level 4 (deepest)
- b1: two dirs at level 3
- d1: file at level 2
Set up the repo
$ hg init test
$ cd test
$ mkdir -p a1/a2/a3/a4
$ mkdir -p b1/b2/b3/b4
$ mkdir -p b1/b2/b3/c4
$ mkdir -p d1/d2/d3/d4
$ echo foo > a1/a2/a3/a4/foo
$ echo foo > b1/b2/b3/b4/foo
$ echo foo > b1/b2/b3/c4/foo
$ echo foo > d1/d2/d3/d4/foo
$ echo foo > d1/d2/foo
$ hg ci -Ama
adding a1/a2/a3/a4/foo
adding b1/b2/b3/b4/foo
adding b1/b2/b3/c4/foo
adding d1/d2/d3/d4/foo
adding d1/d2/foo
$ hg serve -n test -p $HGPORT -d --pid-file=hg.pid -E errors.log
$ cat hg.pid >> $DAEMON_PIDS
manifest with descending (paper)
$ get-with-headers.py 127.0.0.1:$HGPORT 'file'
200 Script output follows
<!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>test: c9f45f7a1659 /</title>
</head>
<body>
<div class="container">
<div class="menu">
<div class="logo">
<a href="https://mercurial-scm.org/">
<img src="/static/hglogo.png" alt="mercurial" /></a>
</div>
<ul>
<li><a href="/shortlog/tip">log</a></li>
<li><a href="/graph/tip">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="/rev/tip">changeset</a></li>
<li class="active">browse</li>
</ul>
<ul>
</ul>
<ul>
<li><a href="/help">help</a></li>
</ul>
</div>
<div class="main">
<h2 class="breadcrumb"><a href="/">Mercurial</a> </h2>
<h3>
directory / @ 0:<a href="/rev/c9f45f7a1659">c9f45f7a1659</a>
<span class="tag">tip</span>
</h3>
<form class="search" action="/log">
<p><input name="rev" id="search1" type="text" size="30" /></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>
<table class="bigtable">
<thead>
<tr>
<th class="name">name</th>
<th class="size">size</th>
<th class="permissions">permissions</th>
</tr>
</thead>
<tbody class="stripes2">
<tr class="fileline">
<td class="name"><a href="/file/tip/">[up]</a></td>
<td class="size"></td>
<td class="permissions">drwxr-xr-x</td>
</tr>
<tr class="fileline">
<td class="name">
<a href="/file/tip/a1">
<img src="/static/coal-folder.png" alt="dir."/> a1/
</a>
<a href="/file/tip/a1/a2/a3/a4">
a2/a3/a4
</a>
</td>
<td class="size"></td>
<td class="permissions">drwxr-xr-x</td>
</tr>
<tr class="fileline">
<td class="name">
<a href="/file/tip/b1">
<img src="/static/coal-folder.png" alt="dir."/> b1/
</a>
<a href="/file/tip/b1/b2/b3">
b2/b3
</a>
</td>
<td class="size"></td>
<td class="permissions">drwxr-xr-x</td>
</tr>
<tr class="fileline">
<td class="name">
<a href="/file/tip/d1">
<img src="/static/coal-folder.png" alt="dir."/> d1/
</a>
<a href="/file/tip/d1/d2">
d2
</a>
</td>
<td class="size"></td>
<td class="permissions">drwxr-xr-x</td>
</tr>
</tbody>
</table>
</div>
</div>
<script type="text/javascript">process_dates()</script>
</body>
</html>
manifest with descending (coal)
$ get-with-headers.py 127.0.0.1:$HGPORT 'file?style=coal'
200 Script output follows
<!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" />
<link rel="stylesheet" href="/static/style-extra-coal.css" type="text/css" />
<script type="text/javascript" src="/static/mercurial.js"></script>
<title>test: c9f45f7a1659 /</title>
</head>
<body>
<div class="container">
<div class="menu">
<div class="logo">
<a href="https://mercurial-scm.org/">
<img src="/static/hglogo.png" alt="mercurial" /></a>
</div>
<ul>
<li><a href="/shortlog/tip?style=coal">log</a></li>
<li><a href="/graph/tip?style=coal">graph</a></li>
<li><a href="/tags?style=coal">tags</a></li>
<li><a href="/bookmarks?style=coal">bookmarks</a></li>
<li><a href="/branches?style=coal">branches</a></li>
</ul>
<ul>
<li><a href="/rev/tip?style=coal">changeset</a></li>
<li class="active">browse</li>
</ul>
<ul>
</ul>
<ul>
<li><a href="/help?style=coal">help</a></li>
</ul>
</div>
<div class="main">
<h2 class="breadcrumb"><a href="/">Mercurial</a> </h2>
<h3>
directory / @ 0:<a href="/rev/c9f45f7a1659?style=coal">c9f45f7a1659</a>
<span class="tag">tip</span>
</h3>
<form class="search" action="/log">
<input type="hidden" name="style" value="coal" />
<p><input name="rev" id="search1" type="text" size="30" /></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>
<table class="bigtable">
<thead>
<tr>
<th class="name">name</th>
<th class="size">size</th>
<th class="permissions">permissions</th>
</tr>
</thead>
<tbody class="stripes2">
<tr class="fileline">
<td class="name"><a href="/file/tip/?style=coal">[up]</a></td>
<td class="size"></td>
<td class="permissions">drwxr-xr-x</td>
</tr>
<tr class="fileline">
<td class="name">
<a href="/file/tip/a1?style=coal">
<img src="/static/coal-folder.png" alt="dir."/> a1/
</a>
<a href="/file/tip/a1/a2/a3/a4?style=coal">
a2/a3/a4
</a>
</td>
<td class="size"></td>
<td class="permissions">drwxr-xr-x</td>
</tr>
<tr class="fileline">
<td class="name">
<a href="/file/tip/b1?style=coal">
<img src="/static/coal-folder.png" alt="dir."/> b1/
</a>
<a href="/file/tip/b1/b2/b3?style=coal">
b2/b3
</a>
</td>
<td class="size"></td>
<td class="permissions">drwxr-xr-x</td>
</tr>
<tr class="fileline">
<td class="name">
<a href="/file/tip/d1?style=coal">
<img src="/static/coal-folder.png" alt="dir."/> d1/
</a>
<a href="/file/tip/d1/d2?style=coal">
d2
</a>
</td>
<td class="size"></td>
<td class="permissions">drwxr-xr-x</td>
</tr>
</tbody>
</table>
</div>
</div>
<script type="text/javascript">process_dates()</script>
</body>
</html>
manifest with descending (monoblue)
$ get-with-headers.py 127.0.0.1:$HGPORT 'file?style=monoblue'
200 Script output follows
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<link rel="icon" href="/static/hgicon.png" type="image/png" />
<meta name="robots" content="index, nofollow"/>
<link rel="stylesheet" href="/static/style-monoblue.css" type="text/css" />
<script type="text/javascript" src="/static/mercurial.js"></script>
<title>test: files</title>
<link rel="alternate" type="application/atom+xml" href="/atom-log" title="Atom feed for test"/>
<link rel="alternate" type="application/rss+xml" href="/rss-log" title="RSS feed for test"/>
</head>
<body>
<div id="container">
<div class="page-header">
<h1 class="breadcrumb"><a href="/">Mercurial</a> / files</h1>
<form action="/log">
<input type="hidden" name="style" value="monoblue" />
<dl class="search">
<dt><label>Search: </label></dt>
<dd><input type="text" name="rev" /></dd>
</dl>
</form>
<ul class="page-nav">
<li><a href="/summary?style=monoblue">summary</a></li>
<li><a href="/shortlog?style=monoblue">shortlog</a></li>
<li><a href="/changelog?style=monoblue">changelog</a></li>
<li><a href="/graph/tip?style=monoblue">graph</a></li>
<li><a href="/tags?style=monoblue">tags</a></li>
<li><a href="/bookmarks?style=monoblue">bookmarks</a></li>
<li><a href="/branches?style=monoblue">branches</a></li>
<li class="current">files</li>
<li><a href="/help?style=monoblue">help</a></li>
</ul>
</div>
<ul class="submenu">
<li><a href="/rev/tip?style=monoblue">changeset</a></li>
</ul>
<h2 class="no-link no-border">files</h2>
<p class="files">/ <span class="logtags"><span class="branchtag" title="default">default</span> <span class="tagtag" title="tip">tip</span> </span></p>
<table>
<tr class="parity0">
<td>drwxr-xr-x</td>
<td></td>
<td></td>
<td><a href="/file/tip/?style=monoblue">[up]</a></td>
<td class="link"> </td>
</tr>
<tr class="parity1">
<td>drwxr-xr-x</td>
<td></td>
<td></td>
<td>
<a href="/file/tip/a1?style=monoblue">a1</a>
<a href="/file/tip/a1/a2/a3/a4?style=monoblue">a2/a3/a4</a>
</td>
<td><a href="/file/tip/a1?style=monoblue">files</a></td>
</tr>
<tr class="parity0">
<td>drwxr-xr-x</td>
<td></td>
<td></td>
<td>
<a href="/file/tip/b1?style=monoblue">b1</a>
<a href="/file/tip/b1/b2/b3?style=monoblue">b2/b3</a>
</td>
<td><a href="/file/tip/b1?style=monoblue">files</a></td>
</tr>
<tr class="parity1">
<td>drwxr-xr-x</td>
<td></td>
<td></td>
<td>
<a href="/file/tip/d1?style=monoblue">d1</a>
<a href="/file/tip/d1/d2?style=monoblue">d2</a>
</td>
<td><a href="/file/tip/d1?style=monoblue">files</a></td>
</tr>
</table>
<script type="text/javascript">process_dates()</script>
<div class="page-footer">
<p>Mercurial Repository: test</p>
<ul class="rss-logo">
<li><a href="/rss-log">RSS</a></li>
<li><a href="/atom-log">Atom</a></li>
</ul>
</div>
<div id="powered-by">
<p><a href="https://mercurial-scm.org/" title="Mercurial"><img src="/static/hglogo.png" width=75 height=90 border=0 alt="mercurial" /></a></p>
</div>
</div>
</body>
</html>
manifest with descending (gitweb)
$ get-with-headers.py 127.0.0.1:$HGPORT 'file?style=gitweb'
200 Script output follows
<?xml version="1.0" encoding="ascii"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en-US" 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-gitweb.css" type="text/css" />
<script type="text/javascript" src="/static/mercurial.js"></script>
<title>test: files</title>
<link rel="alternate" type="application/atom+xml"
href="/atom-log" title="Atom feed for test"/>
<link rel="alternate" type="application/rss+xml"
href="/rss-log" title="RSS feed for test"/>
</head>
<body>
<div class="page_header">
<a href="https://mercurial-scm.org/" title="Mercurial" style="float: right;">Mercurial</a>
<a href="/">Mercurial</a> / files
</div>
<div class="page_nav">
<a href="/summary?style=gitweb">summary</a> |
<a href="/shortlog?style=gitweb">shortlog</a> |
<a href="/log?style=gitweb">changelog</a> |
<a href="/graph?style=gitweb">graph</a> |
<a href="/tags?style=gitweb">tags</a> |
<a href="/bookmarks?style=gitweb">bookmarks</a> |
<a href="/branches?style=gitweb">branches</a> |
files |
<a href="/rev/tip?style=gitweb">changeset</a> |
<a href="/help?style=gitweb">help</a>
<br/>
</div>
<div class="title">/ <span class="logtags"><span class="branchtag" title="default">default</span> <span class="tagtag" title="tip">tip</span> </span></div>
<table cellspacing="0">
<tr class="parity0">
<td style="font-family:monospace">drwxr-xr-x</td>
<td style="font-family:monospace"></td>
<td style="font-family:monospace"></td>
<td><a href="/file/tip/?style=gitweb">[up]</a></td>
<td class="link"> </td>
</tr>
<tr class="parity1">
<td style="font-family:monospace">drwxr-xr-x</td>
<td style="font-family:monospace"></td>
<td style="font-family:monospace"></td>
<td>
<a href="/file/tip/a1?style=gitweb">a1</a>
<a href="/file/tip/a1/a2/a3/a4?style=gitweb">a2/a3/a4</a>
</td>
<td class="link">
<a href="/file/tip/a1?style=gitweb">files</a>
</td>
</tr>
<tr class="parity0">
<td style="font-family:monospace">drwxr-xr-x</td>
<td style="font-family:monospace"></td>
<td style="font-family:monospace"></td>
<td>
<a href="/file/tip/b1?style=gitweb">b1</a>
<a href="/file/tip/b1/b2/b3?style=gitweb">b2/b3</a>
</td>
<td class="link">
<a href="/file/tip/b1?style=gitweb">files</a>
</td>
</tr>
<tr class="parity1">
<td style="font-family:monospace">drwxr-xr-x</td>
<td style="font-family:monospace"></td>
<td style="font-family:monospace"></td>
<td>
<a href="/file/tip/d1?style=gitweb">d1</a>
<a href="/file/tip/d1/d2?style=gitweb">d2</a>
</td>
<td class="link">
<a href="/file/tip/d1?style=gitweb">files</a>
</td>
</tr>
</table>
<script type="text/javascript">process_dates()</script>
<div class="page_footer">
<div class="page_footer_text">test</div>
<div class="rss_logo">
<a href="/rss-log">RSS</a>
<a href="/atom-log">Atom</a>
</div>
<br />
</div>
</body>
</html>
manifest with descending (spartan)
$ get-with-headers.py 127.0.0.1:$HGPORT 'file?style=spartan'
200 Script output follows
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<link rel="icon" href="/static/hgicon.png" type="image/png">
<meta name="robots" content="index, nofollow" />
<link rel="stylesheet" href="/static/style.css" type="text/css" />
<script type="text/javascript" src="/static/mercurial.js"></script>
<title>test: files for changeset c9f45f7a1659</title>
</head>
<body>
<div class="buttons">
<a href="/log/tip?style=spartan">changelog</a>
<a href="/shortlog/tip?style=spartan">shortlog</a>
<a href="/graph/tip?style=spartan">graph</a>
<a href="/tags?style=spartan">tags</a>
<a href="/branches?style=spartan">branches</a>
<a href="/rev/tip?style=spartan">changeset</a>
<a href="/help?style=spartan">help</a>
</div>
<h2><a href="/">Mercurial</a> / files for changeset <a href="/rev/c9f45f7a1659">c9f45f7a1659</a>: /</h2>
<table cellpadding="0" cellspacing="0">
<tr class="parity0">
<td><tt>drwxr-xr-x</tt>
<td>
<td>
<td><a href="/file/tip/?style=spartan">[up]</a>
</tr>
<tr class="parity1">
<td><tt>drwxr-xr-x</tt>
<td>
<td>
<td>
<a href="/file/tip/a1?style=spartan">a1/</a>
<a href="/file/tip/a1/a2/a3/a4?style=spartan">
a2/a3/a4
</a>
<tr class="parity0">
<td><tt>drwxr-xr-x</tt>
<td>
<td>
<td>
<a href="/file/tip/b1?style=spartan">b1/</a>
<a href="/file/tip/b1/b2/b3?style=spartan">
b2/b3
</a>
<tr class="parity1">
<td><tt>drwxr-xr-x</tt>
<td>
<td>
<td>
<a href="/file/tip/d1?style=spartan">d1/</a>
<a href="/file/tip/d1/d2?style=spartan">
d2
</a>
</table>
<script type="text/javascript">process_dates()</script>
<div class="logo">
<a href="https://mercurial-scm.org/">
<img src="/static/hglogo.png" width=75 height=90 border=0 alt="mercurial"></a>
</div>
</body>
</html>
$ cat errors.log
$ cd ..