hgweb: send proper HTTP response after uncaught exception
This patch fixes a bug where hgweb would send an incomplete HTTP
response.
If an uncaught exception is raised when hgweb is processing a request,
hgweb attempts to send a generic error response and log that exception.
The server defaults to chunked transfer coding. If an uncaught exception
occurred, it was sending the error response string / chunk properly.
However, RFC 7230 Section 4.1 mandates a 0 size last chunk be sent to
indicate end of the entity body. hgweb was failing to send this last
chunk. As a result, properly written HTTP clients would assume more data
was coming and they would likely time out waiting for another chunk to
arrive.
Mercurial's own test harness was paving over the improper HTTP behavior
by not attempting to read the response body if the status code was 500.
This incorrect workaround was added in ba6577a19656 and has been removed
with this patch.
Mercurial supports a functional language for selecting a set of
revisions.
The language supports a number of predicates which are joined by infix
operators. Parenthesis can be used for grouping.
Identifiers such as branch names may need quoting with single or
double quotes if they contain characters like ``-`` or if they match
one of the predefined predicates.
Special characters can be used in quoted identifiers by escaping them,
e.g., ``\n`` is interpreted as a newline. To prevent them from being
interpreted, strings can be prefixed with ``r``, e.g. ``r'...'``.
There is a single prefix operator:
``not x``
Changesets not in x. Short form is ``! x``.
These are the supported infix operators:
``x::y``
A DAG range, meaning all changesets that are descendants of x and
ancestors of y, including x and y themselves. If the first endpoint
is left out, this is equivalent to ``ancestors(y)``, if the second
is left out it is equivalent to ``descendants(x)``.
An alternative syntax is ``x..y``.
``x:y``
All changesets with revision numbers between x and y, both
inclusive. Either endpoint can be left out, they default to 0 and
tip.
``x and y``
The intersection of changesets in x and y. Short form is ``x & y``.
``x or y``
The union of changesets in x and y. There are two alternative short
forms: ``x | y`` and ``x + y``.
``x - y``
Changesets in x but not in y.
``x^n``
The nth parent of x, n == 0, 1, or 2.
For n == 0, x; for n == 1, the first parent of each changeset in x;
for n == 2, the second parent of changeset in x.
``x~n``
The nth first ancestor of x; ``x~0`` is x; ``x~3`` is ``x^^^``.
There is a single postfix operator:
``x^``
Equivalent to ``x^1``, the first parent of each changeset in x.
The following predicates are supported:
.. predicatesmarker
New predicates (known as "aliases") can be defined, using any combination of
existing predicates or other aliases. An alias definition looks like::
<alias> = <definition>
in the ``revsetalias`` section of a Mercurial configuration file. Arguments
of the form `$1`, `$2`, etc. are substituted from the alias into the
definition.
For example,
::
[revsetalias]
h = heads()
d($1) = sort($1, date)
rs($1, $2) = reverse(sort($1, $2))
defines three aliases, ``h``, ``d``, and ``rs``. ``rs(0:tip, author)`` is
exactly equivalent to ``reverse(sort(0:tip, author))``.
Command line equivalents for :hg:`log`::
-f -> ::.
-d x -> date(x)
-k x -> keyword(x)
-m -> merge()
-u x -> user(x)
-b x -> branch(x)
-P x -> !::x
-l x -> limit(expr, x)
Some sample queries:
- Changesets on the default branch::
hg log -r "branch(default)"
- Changesets on the default branch since tag 1.5 (excluding merges)::
hg log -r "branch(default) and 1.5:: and not merge()"
- Open branch heads::
hg log -r "head() and not closed()"
- Changesets between tags 1.3 and 1.5 mentioning "bug" that affect
``hgext/*``::
hg log -r "1.3::1.5 and keyword(bug) and file('hgext/*')"
- Changesets committed in May 2008, sorted by user::
hg log -r "sort(date('May 2008'), user)"
- Changesets mentioning "bug" or "issue" that are not in a tagged
release::
hg log -r "(keyword(bug) or keyword(issue)) and not ancestors(tag())"