Mercurial > hg
view mercurial/help/environment.txt @ 31956:c13ff31818b0
ui: add special-purpose atexit functionality
In spite of its longstanding use, Python's built-in atexit code is
not suitable for Mercurial's purposes, for several reasons:
* Handlers run after application code has finished.
* Because of this, the code that runs handlers swallows exceptions
(since there's no possible stacktrace to associate errors with).
If we're lucky, we'll get something spat out to stderr (if stderr
still works), which of course isn't any use in a big deployment
where it's important that exceptions get logged and aggregated.
* Mercurial's current atexit handlers make unfortunate assumptions
about process state (specifically stdio) that, coupled with the
above problems, make it impossible to deal with certain categories
of error (try "hg status > /dev/full" on a Linux box).
* In Python 3, the atexit implementation is completely hidden, so
we can't hijack the platform's atexit code to run handlers at a
time of our choosing.
As a result, here's a perfectly cromulent atexit-like implementation
over which we have control. This lets us decide exactly when the
handlers run (after each request has completed), and control what
the process state is when that occurs (and afterwards).
author | Bryan O'Sullivan <bryano@fb.com> |
---|---|
date | Tue, 11 Apr 2017 14:54:12 -0700 |
parents | 77e566fe31ec |
children | 40785ccab410 |
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HG Path to the 'hg' executable, automatically passed when running hooks, extensions or external tools. If unset or empty, this is the hg executable's name if it's frozen, or an executable named 'hg' (with %PATHEXT% [defaulting to COM/EXE/BAT/CMD] extensions on Windows) is searched. HGEDITOR This is the name of the editor to run when committing. See EDITOR. (deprecated, use configuration file) HGENCODING This overrides the default locale setting detected by Mercurial. This setting is used to convert data including usernames, changeset descriptions, tag names, and branches. This setting can be overridden with the --encoding command-line option. HGENCODINGMODE This sets Mercurial's behavior for handling unknown characters while transcoding user input. The default is "strict", which causes Mercurial to abort if it can't map a character. Other settings include "replace", which replaces unknown characters, and "ignore", which drops them. This setting can be overridden with the --encodingmode command-line option. HGENCODINGAMBIGUOUS This sets Mercurial's behavior for handling characters with "ambiguous" widths like accented Latin characters with East Asian fonts. By default, Mercurial assumes ambiguous characters are narrow, set this variable to "wide" if such characters cause formatting problems. HGMERGE An executable to use for resolving merge conflicts. The program will be executed with three arguments: local file, remote file, ancestor file. (deprecated, use configuration file) HGRCPATH A list of files or directories to search for configuration files. Item separator is ":" on Unix, ";" on Windows. If HGRCPATH is not set, platform default search path is used. If empty, only the .hg/hgrc from the current repository is read. For each element in HGRCPATH: - if it's a directory, all files ending with .rc are added - otherwise, the file itself will be added HGPLAIN When set, this disables any configuration settings that might change Mercurial's default output. This includes encoding, defaults, verbose mode, debug mode, quiet mode, tracebacks, and localization. This can be useful when scripting against Mercurial in the face of existing user configuration. Equivalent options set via command line flags or environment variables are not overridden. HGPLAINEXCEPT This is a comma-separated list of features to preserve when HGPLAIN is enabled. Currently the following values are supported: ``alias`` Don't remove aliases. ``i18n`` Preserve internationalization. ``revsetalias`` Don't remove revset aliases. ``templatealias`` Don't remove template aliases. ``progress`` Don't hide progress output. Setting HGPLAINEXCEPT to anything (even an empty string) will enable plain mode. HGUSER This is the string used as the author of a commit. If not set, available values will be considered in this order: - HGUSER (deprecated) - configuration files from the HGRCPATH - EMAIL - interactive prompt - LOGNAME (with ``@hostname`` appended) (deprecated, use configuration file) EMAIL May be used as the author of a commit; see HGUSER. LOGNAME May be used as the author of a commit; see HGUSER. VISUAL This is the name of the editor to use when committing. See EDITOR. EDITOR Sometimes Mercurial needs to open a text file in an editor for a user to modify, for example when writing commit messages. The editor it uses is determined by looking at the environment variables HGEDITOR, VISUAL and EDITOR, in that order. The first non-empty one is chosen. If all of them are empty, the editor defaults to 'vi'. PYTHONPATH This is used by Python to find imported modules and may need to be set appropriately if this Mercurial is not installed system-wide.