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`)
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`
* 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>
This PR moves all compile-time configuration to a single module,
simplifying documentation and access to these features.
Upcomfing features may be enabled either individually, or through a new
`chronosPreviewV4` catch-all designed to allow code to be prepared for
increased strictness in future chronos releases.
`-d:chronosDebug` may be used to enable the existing debugging helpers
together.
Allow `type = proc(...) {.async.}` for pre-declaring async callback
types - in this case, the macro applies the correct transformation to
the return type and adds the appropriate exception / gcsafe annotations
* Fix some warnings messages.
* More warning fixes.
* Address review comments.
Fix MacOS issues.
* More warning fixes.
* More Windows specific fixes.
* Fix macos and windows warnings.
* Fix warnings in timer.nim
Refactor to remove `result`.
Improve performance and behavior of timer to string procedure.
Add tests.
* exception tracking
This PR adds minimal exception tracking to chronos, moving the goalpost
one step further.
In particular, it becomes invalid to raise exceptions from `callSoon`
callbacks: this is critical for writing correct error handling because
there's no reasonable way that a user of chronos can possibly _reason_
about exceptions coming out of there: the event loop will be in an
indeterminite state when the loop is executing an _random_ callback.
As expected, there are several issues in the error handling of chronos:
in particular, it will end up in an inconsistent internal state whenever
the selector loop operations fail, because the internal state update
functions are not written in an exception-safe way. This PR turns this
into a Defect, which probably is not the optimal way of handling things
- expect more work to be done here.
Some API have no way of reporting back errors to callers - for example,
when something fails in the accept loop, there's not much it can do, and
no way to report it back to the user of the API - this has been fixed
with the new accept flow - the old one should be deprecated.
Finally, there is information loss in the API: in composite operations
like `poll` and `waitFor` there's no way to differentiate internal
errors from user-level errors originating from callbacks.
* store `CatchableError` in future
* annotate proc's with correct raises information
* `selectors2` to avoid non-CatchableError IOSelectorsException
* `$` should never raise
* remove unnecessary gcsafe annotations
* fix exceptions leaking out of timer waits
* fix some imports
* functions must signal raising the union of all exceptions across all
platforms to enable cross-platform code
* switch to unittest2
* add `selectors2` which supercedes the std library version and fixes
several exception handling issues in there
* fixes
* docs, platform-independent eh specifiers for some functions
* add feature flag for strict exception mode
also bump version to 3.0.0 - _most_ existing code should be compatible
with this version of exception handling but some things might need
fixing - callbacks, existing raises specifications etc.
* fix AsyncCheck for non-void T
Jacek Sieka
Tanguy
Eugene Kabanov