Normally, it's impossible to generate lots of `eq?`-hashing
collisions, but when the compiler inlines a function, it can duplicate
variables in a way that gives each copy the same `eq?` hash code. The
immutable-hash tree implementation failed when more than 32 collisions
occurred (which triggers a subtree in the collision node).
It's similarly very difficult to generate > 32 values that collide on
`eqv?` hashes but are not `eqv?` (although it must be possible using
exact rationals or complex numbers).
The rktio conversion lost the deregistration of file descriptors in an
internal fd-to-semaphore table building on kqueue/epoll, causing the
wrong semaphore to be checked for a later recycling of the file
descriptor. This bug mainly affects Linux and ports created by
`subprocess`, since kqueue is not used for pipes on Mac OS and BSD
variants. The bug does not affect network sockets (which are the
primary intended clients of epoll/kqueue support), since the relevant
semaphore is deregistered when a socket is closed.
Thanks to James Bornholt for discovering the problem and providing the
repair.
Closes#1769
Fix a problem with compile-time bindings added to a
namespace created by `module->namespace` for a module
that does not have a source file.
Possibly, there's a different fault that should be fixed that caused a
binding to use the module's instantiation-time module path index
instead of its compile-time module path index (which is what happens
when a file is involved). This repair fixes the problem in a general
way, though, and leaves further improvement to the reimplementation of
the expander in Racket (which already does not suffer from the bug).
Thanks to Alexis for providing the example.
In a non-tail position, a JIT-generated application of `apply`
retained the argument list until the called function returned.
Fix it to drop the reference to the list before the function
is called.
And unquoted-printing string contains a string to `display` in all
print modes. Although it could be implemented with a structure type
that has a printing function, `raise-arguments-error` further treats
unquoted-printing strings specially by not using the error value
conversion handler, so it reliably produces literal text in the error
message; that way, `raise-arguments-error` can be used to construct
more error messages.
The hack to implement `_union` without help from libffi failed when
the total size of the variants is too large. Try a different approach,
which involves a bet that the total size plus whether the content is
all floating-point numbers will be enough information for most cases.
Relevant to #1351
Add guard, if first argument to `find-relative-path` is not a path,
then don't call `path-convention-type` on it.
Thanks to Jack Firth for reporting:
https://github.com/racket/rackunit/pull/46
Avoid printing `(unquote @d)` or `(unsyntax @d)` as `,@d` or `#,@d`,
which would mean `(unquote-splicing @d)` or `(unsyntax-splicing @d)`
to the reader, by adding an extra space before the `@`.
Additionally this adds macros that distinguish between the chaperone redirects of prop-only vector
chaperones, function chaperones, and structure chaperones since each of these may store a vector
in the redirects field.
Auto fields were incorrectly recorded as immutable in a structure type
that is first generated from the prefab struct key instead of
`make-struct-type`.
Thanks to Deren Dohoda for the report.
In the process of extracting minimal Windows path encoding for rktio,
I noticed a decoding issue with a path that ends with an unpaired
high-surrogate value. Add a suitable tests and fix the old decoder
(although it will probably go away).
Closes#1721, which points out that the `for/list` expansion
introduced in commit 5e94a906cd interacts badly with a body
that captures a continuation plus Racket's current implemenation
of continuations.
When Racket one day gets a better implementation of continuations,
this change could be considered again, but the general question is
whether programs can detect or be affected by the size of the
continuation (when the programs don't directly control the
continuation creation --- otherwise continuation marks obviously
expose the size).
For a term
(lambda (arg-id ...) (define def-id _rhs) ... (arg-id def-id) ...)
the expander could take quadratic time in the number of `def-id`s
due to walking an environment to remove use-site scopes. (The
variant of the expander rewritten in Racket didn't have this
problem.)
This make-c-id allows an author to specify a convention for how
to connect and identifier defined with define-ffi-definer and
the actual symbol in the file.
* Adds docs.
* Adds tests.
* Adds history.
An authentic structure type is one whose instances cannot be
impersonated or chaperoned. The intended use of `prop:authentic` is to
annotate a library-private data structure where impersonators are
never needed internally for the data structure, and the declaration
lets the compiler produce less code and fewer branches by omitting
impersonator support.
When comparing a part of a hamt that is a collision node versus a
subtree node, a "hash code" was extracted from the collision node ---
but that's really a code for an integer key is that used for the
collision element. The comparison should instead use a code extracted
from the reference to the collision node (which is the code that is
common to all colliding keys).
Avoid the well-known possibility of quadratic handling of ephemeron
chains, where all ephemerons are immediately known, no keys are
immediately known, and each link in the chain has a value that refers
to the next link's key.
To aviod quadratic behior, attach a list of ephemerons to each page of
allocated objecst, where marking any object on the page triggers a
rescan of the ephemerons without waiting to rescan all ephemerons.
The test cases relied on arity and changing log to have an arity
of both 1 and 2 activated new (incorrect) tests. I fixed the
incorrect tests as they applied to the log function.
Make `log` in `racket/base` optionally accept a second argument.
The second argument is the log `base`. The docs also recommend
`fllogb` when precision is important.
* Error message when base is 1
* Added docs.
* Add tests.
Optimization to convert `(hash-ref <ht> <key> (lambda () <constant>))`
to `(hash-ref <ht> <key> <constant>)` didn't check that the `lambda`
for had zero argument.
Closes#1648
