Reentrancy causes event reordering and stack explosions, in addition to
leading to hard-to-debug scenarios.
Since none of chronos is actually tested under reentrant conditions (ie
that all features such as exceptions, cancellations, buffer operations,
timers etc work reliably when the loop is reentered), this is hard to
support over time and prevents useful optimizations - this PR simply
detects and disallows the behaviour to remove the uncertainty,
simplifying reasoning about the event loop in general.
Dedicated exceptions for `read` failures reduce the risk of mixing up
"user" exceptions with those of Future itself. The risk still exists, if
the user allows a chronos exception to bubble up explicitly.
Because `await` structurally guarantees that the Future is not `pending`
at the time of `read`, it does not raise this new exception.
* introduce `FuturePendingError` and `FutureCompletedError` when
`read`:ing a future of uncertain state
* fix `waitFor` / `read` to return `lent` values
* simplify code generation for `void`-returning async procs
* document `Raising` type helper
With these fixes, `transports`/`asyncsync` correctly propagate and document their raises information - generally, most transport functions (send etc) raise `TransportError` and `CancelledError` - `closeWait` is special in that it generally doesn't fail.
This PR introduces the syntax `Future[void].Raises([types])` to create the `InternalRaisesFuture` type with the correct encoding for the types - this allows it to be used in user code while retaining the possibility to change the internal representation down the line.
* introduce raising constraints on stream callbacks - these constraints now give a warning when called with a callback that can raise exceptions (raising callbacks would crash
* fix fail and its tests, which wasn't always given a good generic match
* work around nim bugs related to macro expansion of generic types
* make sure transports raise only `TransportError`-derived exceptions (and `CancelledError`)
* introduce user guide based on `mdbook`
* set up structure for adding simple `chronos` usage examples
* move most readme content to book
* ci deploys book and api guide automatically
* remove most of existing engine docs (obsolete)
* Fix waitFor() should not exit earlier last callback will be scheduled.
* Tune tests to use less memory.
* Fix `testutils`. There is no more last poll() needed.
* Update chronos/internal/asyncfutures.nim
---------
Co-authored-by: Jacek Sieka <jacek@status.im>
This PR replaces the global strict exception mode with an option to
handle `Exception` per function while at the same time enabling strict
exception checking globally by default as has been planned for v4.
`handleException` mode raises `AsyncExceptionError` to distinguish it
from `ValueError` which may originate from user code.
* remove obsolete 1.2 config options
Per discussion in
https://github.com/status-im/nim-chronos/pull/251#issuecomment-1559233139,
`async: (parameters..)` is introduced as a way to customize the async
transformation instead of relying on separate keywords (like
asyncraises).
Two parameters are available as of now:
`raises`: controls the exception effect tracking
`raw`: disables body transformation
Parameters are added to `async` as a tuple allowing more params to be
added easily in the future:
```nim:
proc f() {.async: (name: value, ...).}`
```
* introduce `asyncraises` to core future utilities
Similar to the introduction of `raises` into a codebase, `asyncraises`
needs to be introduced gradually across all functionality before
deriving benefit.
This is a first introduction along with utilities to manage raises lists
and transform them at compile time.
Several scenarios ensue:
* for trivial cases, adding `asyncraises` is enough and the framework
deduces the rest
* some functions "add" new asyncraises (similar to what `raise` does in
"normal" code) - for example `wait` may raise all exceptions of the
future passed to it and additionally a few of its own - this requires
extending the raises list
* som functions "remove" raises (similar to what `try/except` does) such
as `nocancel` with blocks cancellations and therefore reduce the raising
set
Both of the above cases are currently handled by a macro, but depending
on the situation lead to code organisation issues around return types
and pragma limitations - in particular, to keep `asyncraises`
backwards-compatibility, some code needs to exist in two versions which
somewhat complicates the implementation.
* add `asyncraises` versions for several `asyncfutures` utilities
* when assigning exceptions to a `Future` via `fail`, check at compile
time if possible and at runtime if not that the exception matches
constraints
* fix `waitFor` comments
* move async raises to separate module, implement `or`
* Introduce chronos/internals, move some code
This PR breaks the include dependencies between `asyncfutures2` and
`asyncmacros2` by moving the dispatcher and some other code to a new
module.
This step makes it easier to implement `asyncraises` support for future
utilities like `allFutures` etc avoiding the need to play tricks with
include order etc.
Future PR:s may further articulate the difference between "internal"
stuff subject to API breakage and regular public API intended for end
users (rather than advanced integrators).
* names
* windows fix
* Exception tracking v2
* some fixes
* Nim 1.2 compat
* simpler things
* Fixes for libp2p
* Fixes for strictException
* better await exception check
* Fix for template async proc
* make async work with procTy
* FuturEx is now a ref object type
* add tests
* update test
* update readme
* Switch to asyncraises pragma
* Address tests review comments
* Rename FuturEx to RaiseTrackingFuture
* Fix typo
* Split asyncraises into async, asyncraises
* Add -d:chronosWarnMissingRaises
* Add comment to RaiseTrackingFuture
* Allow standalone asyncraises
* CheckedFuture.fail type checking
* First cleanup
* Remove useless line
* Review comments
* nimble: Remove #head from unittest2
* Remove implict raises: CancelledError
* Move checkFutureExceptions to asyncfutures2
* Small refacto
* small cleanup
* Complete in closure finally
* cleanup tests, add comment
* bump
* chronos is not compatible with nim 1.2 anymore
* re-add readme modifications
* fix special exception handlers
* also propagate excetion type in `read`
* `RaiseTrackingFuture` -> `InternalRaisesFuture`
Use internal naming scheme for RTF (this type should only be accessed
via asyncraises)
* use `internalError` for error reading
* oops
* 2.0 workarounds
* again
* remove try/finally for non-raising functions
* Revert "remove try/finally for non-raising functions"
This reverts commit 86bfeb5c97.
`finally` is needed if code returns early :/
* fixes
* avoid exposing `newInternalRaisesFuture` in manual macro code
* avoid unnecessary codegen for `Future[void]`
* avoid reduntant block around async proc body
* simplify body generation for forward declarations with comment but no
body
* avoid duplicate `gcsafe` annotiations
* line info for return at end of async proc
* expand tests
* fix comments, add defer test
---------
Co-authored-by: Jacek Sieka <jacek@status.im>
* Add callTick and stream cancellation tests.
* Fix stepsAsync() test.
* Cancellation changes.
* Update and add more cancellation tests.
* Fix Posix shutdown call to handle ENOTCONN error.
* With new changes to to cancellation its now possible.
* Refactor testsoon.nim to not produce artifacts after tests are finished.
* Debugging MacOS issue.
* Adjust flaky test times.
* Fix issue.
* Add test for issue #334 which was also addressed in this PR.
Avoid `break` in problematic test.
* Add noCancelWait() call which prohibits cancellation.
Fix closeWait() calls to use noCancelWait() predicate.
Adding sleep to flaky MacOS test.
* Remove all debugging echoes.
* Fix cancelAndWait() which now could perform multiple attempts to cancel target Future (mustCancel behavior).
* Fix issues revealed by switch to different cancelAndWait().
* Address review comments.
* Fix testutils compilation warning.
* Rename callTick() to internalCallTick().
* Add some documentation comments.
* Disable flaky ratelimit test.
* Rename noCancelWait() to noCancel().
Address review comments.
* Unpack `finally/defer` blocks and introduce explicit cleaning of objects.
Add request query to debug information.
* Unroll one more loop to avoid `break`.
Add test for query debug string.
* Fix cancellation behavior.
* Address review comments.
* Initial commit.
* Some fixes.
* More fixes.
* Add first test.
* Further fixes for MacOS/BSD.
* Fixes for Linux.
* Add proper tests.
* Lower number of tests.
* Add threadsync tests to test suite.
* There is no need to run tests when threads are off.
* Address review comments.
Fix the issue with multiple signals.
Add tests.
* Switch to use socketpair() instead of pipes.
Fix semaphoring issue on MacOS/BSD.
Add tests.
* Add single threaded fire/wait tests.
* Refactor chronos trackers to be more simple.
* Refactor trackers.
Add HTTP server trackers.
Refactor HTTP main processing loop.
* Compatibility fixes.
Add checkLeaks().
* Fix posix test issue.
* Add httpdebug module which introduces HTTP connection dumping helpers.
Add tests for it.
* Recover and deprecate old version of Trackers.
* Make public iterators to iterate over all tracker counters available.
Fix asynctests to use public iterators instead private one.
* fix EpollEvent memory layout
on x86_64, `EpollEvent` is packed - the upstream version is correct here
* copy-paste upstream instead
* Adjust lines to be 80 characters per line.
---------
Co-authored-by: cheatfate <eugene.kabanov@status.im>
Jacek Sieka
Eugene Kabanov
Tanguy
Tanguy
diegomrsantos
andri lim
rockcavera