hgignore中的怪异的负面前瞻性处理 [英] Weird negative lookahead handling in hgignore
问题描述
在巨大的源代码树中，我希望Mercurial仅跟踪一个子文件夹.
Out of a huge source tree, i want just one subfolder be tracked by Mercurial.
specific/component/subfolder
在任何体面的正则表达式工具(Regex Coach，regexpal.com)中，以下内容绝对足够(并且可以理解)
In any decent regex tool (Regex Coach, regexpal.com), the following is absolutely sufficient (and understandable)
^(?!specific/component/subfolder).+
同时.hgignore坚持拥有
meanwhile .hgignore insists on having
^(?!extras).+
^extras/(?!extensions).+
^extras/extensions/(?!sharing).+
我在前瞻组中添加斜线后，什么都没有通过.
as soon as i put slash inside the lookahead group, nothing gets through.
在将其称为错误之前(也许还有另一个本地正则表达式解析器?)，我先问一下集体智慧:-)
Before calling this a bug (perhaps of yet another homegrown regex parser?) i ask the collective inteligence :-)
间接获得有关hgignore想要去什么的线索
Credits for indirect clue on what the heck hgignore wants go to
推荐答案
请不要在.hgignore中使用否定的超前查询.真的.每当有人在Stack Overflow中在这里建议它时，我都会让他们知道它不是一个预期的功能，因此无法正常工作.如果假定Mercurial的.hgignore文件是白名单系统，则它将具有真正的白名单语法.这是一个黑名单，应按原样使用.
Just don't use negative lookahead in .hgignore. Really. Every time someone suggests it here in Stack Overflow I chime in letting them know that it doesn't work well because it's not an intended feature. If Mercurial's .hgignore file was supposed to be a whitelist system it would have a real whitelist syntax. It's a blacklist and should be used as such.
否定前瞻语法几乎可以正常工作，因为它不是本地的正则表达式解析器-它是内置在python中的一个语法，如果不使用它，则禁用否定前瞻似乎有点过头，但也许是更好的选择.
The negative lookahead syntax almost-works precisely because it's not a homegrown regex parser -- it's the one built into python and going out of the way do disable negative lookahead seems like overkill, but maybe was the better choice.
两个解决方案比使用永远无法满足您的否定的前瞻性处理要好:
Two solutions better than using the never-going-to-be-satisfying-to-you negative look ahead handling:
- 只需将存储库下移一级-向下移至您实际要跟踪的文件夹中
- -或-将所有内容列入黑名单，然后'hg add'您要跟踪的文件-添加覆盖忽略
严重.这不是预期的功能，它永远无法正常运行，但由于向后兼容的原因而无法删除.
Seriously. This wasn't an intended feature and it's never going to work well but can't be removed for backwards compatibility reasons.
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