Change-Id: Ib02b35887896eab418ba9dde764754538cb23b4f
Reviewed-on: https://go-review.googlesource.com/c/go/+/501277
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Run-TryBot: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@golang.org>
Auto-Submit: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
This clarifies the ambiguity of the TODO word as raised in
golang/go#56625.
Also links the introduction text to each function.
Note: linking from Context methods documentation is blocked for now by
golang/go#59728.
Change-Id: Ie6080bd8dee3a652436b0875ddc5f452287c9493
Reviewed-on: https://go-review.googlesource.com/c/go/+/501115
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: David Chase <drchase@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Run-TryBot: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
The unused analyzer handles dot imports now, so a few tests
have picked up vet errors. This CL errors like:
context/x_test.go:524:47: result of context.WithValue call not used
Change-Id: I711a62fd7b50381f8ea45ac526bf0c946a171047
Reviewed-on: https://go-review.googlesource.com/c/go/+/493598
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Alan Donovan <adonovan@google.com>
Add an AfterFunc function, which registers a function to run after
a context has been canceled.
Add support for contexts that implement an AfterFunc method, which
can be used to avoid the need to start a new goroutine watching
the Done channel when propagating cancellation signals.
Fixes#57928
Change-Id: If0b2cdcc4332961276a1ff57311338e74916259c
Reviewed-on: https://go-review.googlesource.com/c/go/+/482695
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Damien Neil <dneil@google.com>
Reviewed-by: Sameer Ajmani <sameer@golang.org>
Tests in package context cannot depend directly on package testing due to an import cycle.
We resolved this by having test functions in package context_test (x_test.go) forward to
test functions in package context (context_test.go). This is fragile, since it's easy
to add a test to context_test.go and forget to add the forwarding function, and tests
written in this way cannot easily use testing package features like t.Run for subtests.
It turns out that only four test functions actually use unexported members of package
context. This CL moves all except those four to x_test.go and makes them regular tests.
It also updates TestCause to use t.Run and t.Parallel to parallelize its test cases.
It also adds documentation indicating when tests should be added to each file.
Change-Id: Ic60bae32a7a44e07831b5388c9af219d53ba9af3
Reviewed-on: https://go-review.googlesource.com/c/go/+/480375
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Sameer Ajmani <sameer@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Damien Neil <dneil@google.com>
WithoutCancel returns a copy of parent that is not canceled when parent is canceled.
The returned context returns no Deadline or Err, and its Done channel is nil.
Calling Cause on the returned context returns nil.
API changes:
+pkg context, func WithoutCancel(Context) Context
Fixes#40221
Change-Id: Ide29631c08881176a2c2a58409fed9ca6072e65d
Reviewed-on: https://go-review.googlesource.com/c/go/+/479918
Run-TryBot: Sameer Ajmani <sameer@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Small cleanup to remove a couple of needless global variables.
Instead of relying on two instances of emptyCtx having different
addresses, we use different types.
For #26775
Change-Id: I0bc4813e94226f7b3f52bf4b1b3c3a3bbbebcc9e
Reviewed-on: https://go-review.googlesource.com/c/go/+/455455
Reviewed-by: Damien Neil <dneil@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Sameer Ajmani <sameer@golang.org>
ExampleWithDeadline and ExampleWithTimeout used an arbitrary 1-second
timeout for a “blocked” select case, which could fail if the test
goroutine happens to be descheduled for over a second, or perhaps if
an NTP synchronization happens to jump by a second at just the right
time.
Either case is plausible, especially on a heavily-loaded or slow
machine (as is often the case for builders for unusual ports).
Instead of an arbitrary timeout, use a “ready” channel that is never
actually ready.
Fixes#57594.
Change-Id: I9ff68f50b041a3382e7b267c28c5259e886a9d23
Reviewed-on: https://go-review.googlesource.com/c/go/+/460999
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Bryan Mills <bcmills@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Sameer Ajmani <sameer@golang.org>
Run-TryBot: Bryan Mills <bcmills@google.com>
Change-Id: I8d970e8db859bdd17390cfbc22cc2ba0d326ed0c
Reviewed-on: https://go-review.googlesource.com/c/go/+/453735
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@google.com>
Reviewed-by: Sameer Ajmani <sameer@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Extend the context package to allow users to specify why a context was
canceled in the form of an error, the "cause". Users write the cause
by calling WithCancelCause to construct a derived context, then
calling cancel(cause) to cancel the context with the provided cause.
Users retrieve the cause by calling context.Cause(ctx), which returns
the cause of the first cancelation for ctx or any of its parents.
The cause is implemented as a field of cancelCtx, since only cancelCtx
can be canceled. Calling cancel copies the cause to all derived (child)
cancelCtxs. Calling Cause(ctx) finds the nearest parent cancelCtx by
looking up the context value keyed by cancelCtxKey.
API changes:
+pkg context, func Cause(Context) error
+pkg context, func WithCancelCause(Context) (Context, CancelCauseFunc)
+pkg context, type CancelCauseFunc func(error)
Fixes#26356Fixes#51365
Change-Id: I15b62bd454c014db3f4f1498b35204451509e641
Reviewed-on: https://go-review.googlesource.com/c/go/+/375977
Reviewed-by: Damien Neil <dneil@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Sameer Ajmani <sameer@golang.org>
Auto-Submit: Sameer Ajmani <sameer@golang.org>
This reverts commit 964f0c7a30.
Reason: cause increasing timeout in crypto/tls tests on race builders.
Change-Id: Id16d4fcd19c2ca2e89ad4d0c9d55ef1105b19c76
Reviewed-on: https://go-review.googlesource.com/c/go/+/422035
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
Auto-Submit: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
[This CL is part of a sequence implementing the proposal #51082.
The design doc is at https://go.dev/s/godocfmt-design.]
Run the updated gofmt, which reformats doc comments,
on the main repository. Vendored files are excluded.
For #51082.
Change-Id: I7332f099b60f716295fb34719c98c04eb1a85407
Reviewed-on: https://go-review.googlesource.com/c/go/+/384268
Reviewed-by: Jonathan Amsterdam <jba@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
And then revert the bootstrap cmd directories and certain testdata.
And adjust tests as needed.
Not reverting the changes in std that are bootstrapped,
because some of those changes would appear in API docs,
and we want to use any consistently.
Instead, rewrite 'any' to 'interface{}' in cmd/dist for those directories
when preparing the bootstrap copy.
A few files changed as a result of running gofmt -w
not because of interface{} -> any but because they
hadn't been updated for the new //go:build lines.
Fixes#49884.
Change-Id: Ie8045cba995f65bd79c694ec77a1b3d1fe01bb09
Reviewed-on: https://go-review.googlesource.com/c/go/+/368254
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
This follows the spelling choices that the Go project has made for English words.
https://github.com/golang/go/wiki/Spelling
Change-Id: Ie7c586d2cf23020cb492cfff58c0831d2d8d3a78
GitHub-Last-Rev: e16a32cd22
GitHub-Pull-Request: golang/go#45442
Reviewed-on: https://go-review.googlesource.com/c/go/+/308291
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Trust: Emmanuel Odeke <emmanuel@orijtech.com>
Use an atomic.Value to hold the done channel.
Conveniently, we have a mutex handy to coordinate writes to it.
name old time/op new time/op delta
ContextCancelDone-8 67.5ns ±10% 2.2ns ±11% -96.74% (p=0.000 n=30+28)
Fixes#42564
Change-Id: I5d72e0e87fb221d4e230209e5fb4698bea4053c6
Reviewed-on: https://go-review.googlesource.com/c/go/+/288193
Trust: Josh Bleecher Snyder <josharian@gmail.com>
Trust: Sameer Ajmani <sameer@golang.org>
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
The test does not use Done channel, so fix that.
Change-Id: I795feab2e95de815b8b6ee7a7fd90f19f7af7db1
Reviewed-on: https://go-review.googlesource.com/c/go/+/294749
Reviewed-by: Sameer Ajmani <sameer@golang.org>
Trust: Sameer Ajmani <sameer@golang.org>
Trust: Cody Oss <codyoss@google.com>
Run-TryBot: Sameer Ajmani <sameer@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
In CL 223019, I reduced the short timeout in the testLayers helper to
be even shorter than it was. That exposed a racy (time-dependent)
select later in the function, which failed in one of the slower
builders (android-386-emu).
Also streamline the test to make it easier to test with a very high -count flag:
- Run tests that sleep for shortDuration in parallel to reduce latency.
- Use shorter durations in examples to reduce test running time.
- Avoid mutating global state (in package math/rand) in testLayers.
After this change (but not before it),
'go test -run=TestLayersTimeout -count=100000 context' passes on my workstation.
Fixes#38161
Change-Id: Iaf4abe7ac308b2100d8828267cda9f4f8ae4be82
Reviewed-on: https://go-review.googlesource.com/c/go/+/226457
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This commit makes it impossible to create derived contexts with nil parents.
Previously it was possible to create derived contexts with nil parents, and
invalid contexts could propogate through the program. Eventually this can
cause a panic downstream, which is difficult to trace back to the source
of the error.
Although `WithCancel` and `WithDeadline` already panic if `parent` is `nil`, this adds explicit checks to give a useful message in the panic.
Fixes#37908
Change-Id: I70fd01f6539c1b0da0e775fc5457e32e7075e52c
GitHub-Last-Rev: 1b7dadd7db
GitHub-Pull-Request: golang/go#37898
Reviewed-on: https://go-review.googlesource.com/c/go/+/223777
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Many of tests in this package assumed reasonable scheduling latency.
Unfortunately, scheduling latency on builders and CI systems is not
always reasonable.
Rather than expecting that a timeout is detected within a fixed short
interval, we can use (*testing.T).Deadline to portably scale the time
we're willing to wait to something appropriate to the builder.
Some of the tests also included arbitrary-duration sleeps, which are
no longer needed after CL 196521; we can remove those instead of
extending them.
Promptness of timeouts is also an important property, but testing that
property is better suited to benchmarks than to tests proper: unlike
tests, we generally expect benchmarks to be run in a quiet,
low-contention environment.
Fixes#13956
Change-Id: I0797e2267fb778c8ad94add56d797de9e2c885e5
Reviewed-on: https://go-review.googlesource.com/c/go/+/223019
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
If the parent context passed to WithCancel or WithTimeout
is a known context implementation (one created by this package),
we attach the child to the parent by editing data structures directly;
otherwise, for unknown parent implementations, we make a
goroutine that watches for the parent to finish and propagates
the cancellation.
A common problem with this scheme, before this CL, is that
users who write custom context implementations to manage
their value sets cause WithCancel/WithTimeout to start
goroutines that would have not been started before.
This CL changes the way we map a parent context back to the
underlying data structure. Instead of walking up through
known context implementations to reach the *cancelCtx,
we look up parent.Value(&cancelCtxKey) to return the
innermost *cancelCtx, which we use if it matches parent.Done().
This way, a custom context implementation wrapping a
*cancelCtx but not changing Done-ness (and not refusing
to return wrapped keys) will not require a goroutine anymore
in WithCancel/WithTimeout.
For #28728.
Change-Id: Idba2f435c81b19fe38d0dbf308458ca87c7381e9
Reviewed-on: https://go-review.googlesource.com/c/go/+/196521
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
It is unclear whether the current definition of os.IsTimeout is
desirable or not. Drop ErrTimeout for now so we can consider adding it
(or some other error) in a future release with a corrected definition.
Fixes#33411
Change-Id: I8b880da7d22afc343a08339eb5f0efd1075ecafe
Reviewed-on: https://go-review.googlesource.com/c/go/+/188758
Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Damien Neil <dneil@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
As discussed in
https://github.com/golang/go/issues/32463#issuecomment-506833421
the classification of deadline-based timeouts as "temporary" errors is a
historical accident. I/O timeouts used to be duration-based, so they
really were temporary--retrying a timed-out operation could succeed. Now
that they're deadline-based, timeouts aren't temporary unless you reset
the deadline.
Drop ErrTemporary from Go 1.13, since its definition is wrong. We'll
consider putting it back in Go 1.14 with a clear definition and
deprecate net.OpError.Temporary.
Fixes#32463
Change-Id: I70cda664590d8872541e17409a5780da76920891
Reviewed-on: https://go-review.googlesource.com/c/go/+/188398
Reviewed-by: Jonathan Amsterdam <jba@google.com>
Add Unwrap methods to types which wrap an underlying error:
"encodinc/csv".ParseError
"encoding/json".MarshalerError
"net/http".transportReadFromServerError
"net".OpError
"net".DNSConfigError
"net/url".Error
"os/exec".Error
"signal/internal/pty".PtyError
"text/template".ExecError
Add os.ErrTemporary. A case could be made for putting this error
value in package net, since no exported error types in package os
include a Temporary method. However, syscall errors returned from
the os package do include this method.
Add Is methods to error types with a Timeout or Temporary method,
making errors.Is(err, os.Err{Timeout,Temporary}) equivalent to
testing the corresponding method:
"context".DeadlineExceeded
"internal/poll".TimeoutError
"net".adrinfoErrno
"net".OpError
"net".DNSError
"net/http".httpError
"net/http".tlsHandshakeTimeoutError
"net/pipe".timeoutError
"net/url".Error
Updates #30322
Updates #29934
Change-Id: I409fb20c072ea39116ebfb8c7534d493483870dc
Reviewed-on: https://go-review.googlesource.com/c/go/+/170037
Run-TryBot: Damien Neil <dneil@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>
Though there is variation in the spelling of canceled,
cancellation is always spelled with a double l.
Reference: https://www.grammarly.com/blog/canceled-vs-cancelled/
Change-Id: I240f1a297776c8e27e74f3eca566d2bc4c856f2f
Reviewed-on: https://go-review.googlesource.com/c/go/+/170060
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
So the net package doesn't indirectly depend on unicode tables.
But we're still not quite there, because a new test added in this CL
reveals that we still have a path to unicode via:
deps_test.go:570:
TODO(issue 30440): policy violation: net => sort => reflect => unicode
Updates #30440
Change-Id: I710c2061dfbaa8e866c92e6c824bd8df35784165
Reviewed-on: https://go-review.googlesource.com/c/go/+/169080
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Make context depend on reflectlite instead of reflect in effort to
eventually make net no longer depend on unicode tables.
With this CL we're down to just:
net -> context -> fmt -> unicode tables
The next CL can remove context -> fmt.
Updates #30440
Change-Id: I7f5df15f975d9dc862c59aa8477c1cfd6ff4967e
Reviewed-on: https://go-review.googlesource.com/c/go/+/164239
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
When deadline has already passed,
current context is canceled before return cancel function.
So is unnecessary to call cancel with remove from parent again
in return cancel function.
Change-Id: I37c687c57a29d9f139c7fb648ce7de69093ed623
Reviewed-on: https://go-review.googlesource.com/c/50410
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
This comment has been the source of much confusion and broken dreams. We
can add it back if a tool ever gets released.
Updates #16742
Change-Id: I4b9c179b7c60274e6ff1bcb607b82029dd9a893f
Reviewed-on: https://go-review.googlesource.com/130876
Reviewed-by: Matt Layher <mdlayher@gmail.com>
Reviewed-by: Alan Donovan <adonovan@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Docs of WithDeadline refers to variable "d" which does not exist
in the docs.
This commit renames the time argument to "d" to make the doc work.
Change-Id: Ifd2c1be7d2e3f7dfb21cd9bb8ff7fc5039c8d3bd
Reviewed-on: https://go-review.googlesource.com/65130
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Previously, the suggested code would result in the following golint warning:
“should drop = 0 from declaration of var errorsOnlyKey; it is the zero value”
Change-Id: I1a302c1e40ca89acbc76897e39097ecd04865460
Reviewed-on: https://go-review.googlesource.com/60290
Reviewed-by: Ian Lance Taylor <iant@golang.org>
The Context definition to date has not defined what Err returns
before the Done channel is closed. Define that it returns nil,
as most implementations do.
All the standard context implementations (those in package
context and in golang.org/x/net/context) return Err() == nil
when Done is not yet closed. However, some non-standard
implementations may exist that return Err() != nil in this case,
as permitted by the Context definition before this date.
Call these "errorful implementations".
Because all the standard context implementations ensure that
Err() == nil when Done is not yet closed, clients now exist that
assume Err() != nil implies Done is closed and use calling Err
as a quick short-circuit check instead of first doing a non-blocking
receive from Done and then, if that succeeds, needing to call Err.
This assumption holds for all the standard Context implementations,
so these clients work fine in practice, even though they are making
unwarranted assumptions about the Context implementations.
Call these "technically incorrect clients".
If a technically incorrect client encounters an errorful
implementation, the client misbehaves. Because there are few
errorful implementations, over time we expect that many clients
will end up being technically incorrect without realizing it,
leading to latent, subtle bugs. If we want to eliminate these
latent, subtle bugs, there are two ways to do this:
either make errorful implementations more common
(exposing the client bugs more often) or redefine the Context
interface so that the clients are not buggy after all.
If we make errorful implementations more common, such
as by changing the standard context implementations to
return ErrNotDone instead of nil when Err is called before
Done is closed, this will shake out essentially all of the
technically incorrect clients, forcing people to find and fix
those clients during the transition to Go 1.9.
Technically this is allowed by the compatibility policy,
but we expect there are many pieces of code assuming
that Err() != nil means done, so updating will cause real pain.
If instead we disallow errorful implementations, then they
will need to be fixed as they are discovered, but the fault
will officially lie in the errorful Context implementation,
not in the clients. Technically this is disallowed by the compatibility
policy, because these errorful implementations were "correct"
in earlier versions of Go, except that they didn't work with
common client code. We expect there are hardly any errorful
implementations, so that disallowing them will be less disruptive
and more in the spirit of the compatibility policy.
This CL takes the path of expected least disruption,
narrowing the Context interface semantics and potentially
invalidating existing implementations. A survey of the
go-corpus v0.01 turned up only five Context implementations,
all trivial and none errorful (details in #19856).
We are aware of one early Context implementation inside Google,
from before even golang.org/x/net/context existed,
that is errorful. The misbehavior of an open-source library
when passed such a context is what prompted #19856.
That context implementation would be disallowed after this CL
and would need to be corrected. We are aware of no other
affected context implementations. On the other hand, a survey
of the go-corpus v0.01 turned up many instances of client
code assuming that Err() == nil implies not done yet
(details also in #19856). On balance, narrowing Context and
thereby allowing Err() == nil checks should invalidate significantly
less code than a push to flush out all the currently technically
incorrect Err() == nil checks.
If release feedback shows that we're wrong about this balance,
we can roll back this CL and try again in Go 1.10.
Fixes#19856.
Change-Id: Id45d126fac70e1fcc42d73e5a87ca1b66935b831
Reviewed-on: https://go-review.googlesource.com/40291
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Sameer Ajmani <sameer@golang.org>
It could have been defined the other way, but since the behavior has
been unspecified, this is the conservative approach for people writing
different implementations of the Context interface.
Change-Id: I7334a4c674bc2330cca6874f7cac1eb0eaea3cff
Reviewed-on: https://go-review.googlesource.com/37375
Reviewed-by: Matt Layher <mdlayher@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Sameer Ajmani <sameer@golang.org>
Run-TryBot: Sameer Ajmani <sameer@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>