repoview: discard filtered changelog if index isn't shared with unfiltered
Before this patch, revisions rollbacked at failure of previous
transaction might be visible at subsequent operations unintentionally,
if repoview object is reused even after failure of transaction:
e.g. command server and HTTP server are typical cases.
'repoview' uses the tuple of values below of unfiltered changelog as
"the key" to examine validity of filtered changelog cache.
- length
- tip node
- filtered revisions (as hashed value)
- '_delayed' field
'repoview' compares between "the key" of unfiltered changelog at
previous caching and now, and reuses filtered changelog cache if no
change is detected.
But this comparison indicates only that there is no change between
unfiltered 'repo.changelog' at last caching and now, but not that
filtered changelog cache is valid for current unfiltered one.
'repoview' uses "shallow copy" of unfiltered changelog to create
filtered changelog cache. In this case, 'index' buffer of unfiltered
changelog is also referred by filtered changelog.
At failure of transaction, unfiltered changelog itself is invalidated
(= un-referred) on the 'repo' side (see
0a7610758c42 also). But
'index' of it still contains revisions to be rollbacked at this
failure, and is referred by filtered changelog.
Therefore, even if there is no change between unfiltered
'repo.changelog' at last caching and now, steps below makes rollbacked
revisions visible via filtered changelog unintentionally.
1. instantiate unfiltered changelog as 'repo.changelog'
(call it CL1)
2. make filtered (= shallow copy of) CL1
(call it FCL1)
3. cache FCL1 with "the key" of CL1
4. revisions are appended to 'index', which is shared by CL1 and FCL1
5. invalidate 'repo.changelog' (= CL1) at failure of transaction
6. instantiate 'repo.changelog' again at next operation
(call it CL2)
CL2 doesn't have revisions added at (4), because it is
instantiated from '00changelog.i', which isn't changed while
failed transaction.
7. compare between "the key" of CL1 and CL2
8. FCL1 cached at (3) is reused, because comparison at (7) doesn't
detect change between CL1 at (1) and CL2
9. revisions rollbacked at (5) are visible via FCL1 unintentionally,
because FCL1 still refers 'index' changed at (4)
The root cause of this issue is that there is no examination about
validity of filtered changelog cache against current unfiltered one.
This patch discards filtered changelog cache, if its 'index' object
isn't shared with unfiltered one.
BTW, at the time of this patch, redundant truncation of
'00changelog.i' at failure of transaction (see
0a7610758c42 for
detail) often prevents "hg serve" from making already rollbacked
revisions visible, because updating timestamps of '00changelog.i' by
truncation makes "hg serve" discard old repoview object with invalid
filtered changelog cache.
This is reason why this issue is overlooked before this patch, even
though test-bundle2-exchange.t has tests in similar situation: failure
of "hg push" via HTTP by pretxnclose hook on server side doesn't
prevent subsequent commands from looking up outgoing revisions
correctly.
But timestamp on the filesystem doesn't have enough resolution for
recent computation power, and it can't be assumed that this avoidance
always works as expected.
Therefore, without this patch, this issue might appear occasionally.
from pprint import pprint
from mercurial import minirst
def debugformat(text, form, **kwargs):
if form == 'html':
print "html format:"
out = minirst.format(text, style=form, **kwargs)
else:
print "%d column format:" % form
out = minirst.format(text, width=form, **kwargs)
print "-" * 70
if type(out) == tuple:
print out[0][:-1]
print "-" * 70
pprint(out[1])
else:
print out[:-1]
print "-" * 70
print
def debugformats(title, text, **kwargs):
print "== %s ==" % title
debugformat(text, 60, **kwargs)
debugformat(text, 30, **kwargs)
debugformat(text, 'html', **kwargs)
paragraphs = """
This is some text in the first paragraph.
A small indented paragraph.
It is followed by some lines
containing random whitespace.
\n \n \nThe third and final paragraph.
"""
debugformats('paragraphs', paragraphs)
definitions = """
A Term
Definition. The indented
lines make up the definition.
Another Term
Another definition. The final line in the
definition determines the indentation, so
this will be indented with four spaces.
A Nested/Indented Term
Definition.
"""
debugformats('definitions', definitions)
literals = r"""
The fully minimized form is the most
convenient form::
Hello
literal
world
In the partially minimized form a paragraph
simply ends with space-double-colon. ::
////////////////////////////////////////
long un-wrapped line in a literal block
\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
::
This literal block is started with '::',
the so-called expanded form. The paragraph
with '::' disappears in the final output.
"""
debugformats('literals', literals)
lists = """
- This is the first list item.
Second paragraph in the first list item.
- List items need not be separated
by a blank line.
- And will be rendered without
one in any case.
We can have indented lists:
- This is an indented list item
- Another indented list item::
- A literal block in the middle
of an indented list.
(The above is not a list item since we are in the literal block.)
::
Literal block with no indentation (apart from
the two spaces added to all literal blocks).
1. This is an enumerated list (first item).
2. Continuing with the second item.
(1) foo
(2) bar
1) Another
2) List
Line blocks are also a form of list:
| This is the first line.
The line continues here.
| This is the second line.
"""
debugformats('lists', lists)
options = """
There is support for simple option lists,
but only with long options:
-X, --exclude filter an option with a short and long option with an argument
-I, --include an option with both a short option and a long option
--all Output all.
--both Output both (this description is
quite long).
--long Output all day long.
--par This option has two paragraphs in its description.
This is the first.
This is the second. Blank lines may be omitted between
options (as above) or left in (as here).
The next paragraph looks like an option list, but lacks the two-space
marker after the option. It is treated as a normal paragraph:
--foo bar baz
"""
debugformats('options', options)
fields = """
:a: First item.
:ab: Second item. Indentation and wrapping
is handled automatically.
Next list:
:small: The larger key below triggers full indentation here.
:much too large: This key is big enough to get its own line.
"""
debugformats('fields', fields)
containers = """
Normal output.
.. container:: debug
Initial debug output.
.. container:: verbose
Verbose output.
.. container:: debug
Debug output.
"""
debugformats('containers (normal)', containers)
debugformats('containers (verbose)', containers, keep=['verbose'])
debugformats('containers (debug)', containers, keep=['debug'])
debugformats('containers (verbose debug)', containers,
keep=['verbose', 'debug'])
roles = """Please see :hg:`add`."""
debugformats('roles', roles)
sections = """
Title
=====
Section
-------
Subsection
''''''''''
Markup: ``foo`` and :hg:`help`
------------------------------
"""
debugformats('sections', sections)
admonitions = """
.. note::
This is a note
- Bullet 1
- Bullet 2
.. warning:: This is a warning Second
input line of warning
.. danger::
This is danger
"""
debugformats('admonitions', admonitions)
comments = """
Some text.
.. A comment
.. An indented comment
Some indented text.
..
Empty comment above
"""
debugformats('comments', comments)
data = [['a', 'b', 'c'],
['1', '2', '3'],
['foo', 'bar', 'baz this list is very very very long man']]
rst = minirst.maketable(data, 2, True)
table = ''.join(rst)
print table
debugformats('table', table)
data = [['s', 'long', 'line\ngoes on here'],
['', 'xy', 'tried to fix here\n by indenting']]
rst = minirst.maketable(data, 1, False)
table = ''.join(rst)
print table
debugformats('table+nl', table)