Long ago we decided that panic(nil) was too unlikely to bother
making a special case for purposes of recover. Unfortunately,
it has turned out not to be a special case. There are many examples
of code in the Go ecosystem where an author has written panic(nil)
because they want to panic and don't care about the panic value.
Using panic(nil) in this case has the unfortunate behavior of
making recover behave as though the goroutine isn't panicking.
As a result, code like:
func f() {
defer func() {
if err := recover(); err != nil {
log.Fatalf("panicked! %v", err)
}
}()
call1()
call2()
}
looks like it guarantees that call2 has been run any time f returns,
but that turns out not to be strictly true. If call1 does panic(nil),
then f returns "successfully", having recovered the panic, but
without calling call2.
Instead you have to write something like:
func f() {
done := false
defer func() {
if err := recover(); !done {
log.Fatalf("panicked! %v", err)
}
}()
call1()
call2()
done = true
}
which defeats nearly the whole point of recover. No one does this,
with the result that almost all uses of recover are subtly broken.
One specific broken use along these lines is in net/http, which
recovers from panics in handlers and sends back an HTTP error.
Users discovered in the early days of Go that panic(nil) was a
convenient way to jump out of a handler up to the serving loop
without sending back an HTTP error. This was a bug, not a feature.
Go 1.8 added panic(http.ErrAbortHandler) as a better way to access the feature.
Any lingering code that uses panic(nil) to abort an HTTP handler
without a failure message should be changed to use http.ErrAbortHandler.
Programs that need the old, unintended behavior from net/http
or other packages can set GODEBUG=panicnil=1 to stop the run-time error.
Uses of recover that want to detect panic(nil) in new programs
can check for recover returning a value of type *runtime.PanicNilError.
Because the new GODEBUG is used inside the runtime, we can't
import internal/godebug, so there is some new machinery to
cross-connect those in this CL, to allow a mutable GODEBUG setting.
That won't be necessary if we add any other mutable GODEBUG settings
in the future. The CL also corrects the handling of defaulted GODEBUG
values in the runtime, for #56986.
Fixes#25448.
Change-Id: I2b39c7e83e4f7aa308777dabf2edae54773e03f5
Reviewed-on: https://go-review.googlesource.com/c/go/+/461956
Reviewed-by: Robert Griesemer <gri@google.com>
Run-TryBot: Russ Cox <rsc@golang.org>
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CL 444277 fixed Time.UnmarshalText and Time.UnmarshalJSON to properly
unmarshal timestamps according to RFC 3339 instead of according
to Go's bespoke time syntax that is a superset of RFC 3339.
However, this change seems to have broken an AWS S3 unit test
that relies on parsing timestamps with single digit hours.
It is unclear whether S3 emits these timestamps in production or
whether this is simply a testing artifact that has been cargo culted
across many code bases. Either way, disable strict parsing for now
and re-enable later with better GODEBUG support.
Updates #54580
Change-Id: Icced2c7f9a6b2fc06bbd9c7e90f90edce24c2306
Reviewed-on: https://go-review.googlesource.com/c/go/+/462286
Reviewed-by: Bryan Mills <bcmills@google.com>
Run-TryBot: Joseph Tsai <joetsai@digital-static.net>
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Reviewed-by: Ian Lance Taylor <iant@golang.org>
The arena goexperiment contains code used inside Google in very
limited use cases that we will maintain, but the discussion on #51317
identified serious problems with the very idea of adding arenas to the
standard library. In particular the concept tends to infect many other
APIs in the name of efficiency, a bit like sync.Pool except more
publicly visible.
It is unclear when, if ever, we will pick up the idea and try to push
it forward into a public API, but it's not going to happen any time
soon, and we don't want users to start depending on it: it's a true
experiment and may be changed or deleted without warning.
The arena text in the release notes makes them seem more official
and supported than they really are, and we've already seen a couple
blog posts based on that erroneous belief. Delete the text to try to
set expectations better.
Change-Id: I4f6e328ac470a9cd410f5f722d0769ef62d5e5ba
Reviewed-on: https://go-review.googlesource.com/c/go/+/462355
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Reviewed-by: Eli Bendersky <eliben@google.com>
Links under strings package were linking to the bytes versions of the functions.
Change-Id: If6ebe37fede8e417f8683695783aa767bc01e9c7
GitHub-Last-Rev: 8849285122
GitHub-Pull-Request: golang/go#57579
Reviewed-on: https://go-review.googlesource.com/c/go/+/460458
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Reviewed-by: Heschi Kreinick <heschi@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Change-Id: Ie2e583cba9e9bec7d642e323e77fb2d9b05dc7bc
Reviewed-on: https://go-review.googlesource.com/c/go/+/459780
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
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Reviewed-by: Ian Lance Taylor <iant@google.com>
Change-Id: Ia0ce728ca18eefd835220b2076c4aa8ba00cda6d
Reviewed-on: https://go-review.googlesource.com/c/go/+/458815
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
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Reviewed-by: David Chase <drchase@google.com>
Change-Id: Icddf980e533b86ca955660ad028f5ad04b6aecbe
Reviewed-on: https://go-review.googlesource.com/c/go/+/457916
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Reviewed-by: Than McIntosh <thanm@google.com>
Fixes#40882.
Change-Id: I90f99d75e6d66f857b6ab8789c6d436f85d20993
Reviewed-on: https://go-review.googlesource.com/c/go/+/457515
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Reviewed-by: Robert Findley <rfindley@google.com>
For #56548.
Fixes#57012.
Change-Id: I44f850522e52b1811025fb31bcef289da8f8089d
Reviewed-on: https://go-review.googlesource.com/c/go/+/457437
TryBot-Bypass: Robert Griesemer <gri@google.com>
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Reviewed-by: Robert Findley <rfindley@google.com>
Reviewed-by: Robert Griesemer <gri@google.com>
- Rephrase the notion of "comparability" from a property
of values (operands) to a property of types and adjust
dependent prose.
- Introduce the notion of "strict comparability".
- Fix the definitions of comparability for type interfaces
and type parameters.
- Define the predeclared identifier "comparable" as stricly
comparable.
These changes address existing problems in the spec as outlined
in the section on "Related spec issues" in issue #56548.
For #56548.
Change-Id: Ibc8c2f36d92857a5134eadc18358624803d3dd21
Reviewed-on: https://go-review.googlesource.com/c/go/+/457095
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Bypass: Robert Griesemer <gri@google.com>
Reviewed-by: Robert Findley <rfindley@google.com>
Reviewed-by: Robert Griesemer <gri@google.com>
Change-Id: Id0319a9cc9acc549022fdcd6b7d71c7343afd245
GitHub-Last-Rev: 2b84d25763
GitHub-Pull-Request: golang/go#57187
Reviewed-on: https://go-review.googlesource.com/c/go/+/456395
Run-TryBot: Ian Lance Taylor <iant@google.com>
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The -v flag value is "test2json", not "json", since it emits output
in a custom format that the cmd/test2json tool interprets.
The cmd/test2json documentation and implementation have this right.
For #54202.
Change-Id: I2b52861d926e14488aa9fc89fff8c26da32ca710
Reviewed-on: https://go-review.googlesource.com/c/go/+/456124
Reviewed-by: Bryan Mills <bcmills@google.com>
Auto-Submit: Dmitri Shuralyov <dmitshur@golang.org>
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This section is complete.
For #54202.
Change-Id: I304cc55a5b8ed53e8b8dff73a5feb5ef39207846
Reviewed-on: https://go-review.googlesource.com/c/go/+/455895
Run-TryBot: Michael Pratt <mpratt@google.com>
Reviewed-by: Carlos Amedee <carlos@golang.org>
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Add some basic material on the changes to code coverage testing
to the release notes.
For #54202.
Change-Id: I28200d43b4952ce8e8ecf46c8fe8e97c81d245e5
Reviewed-on: https://go-review.googlesource.com/c/go/+/453857
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Reviewed-by: Cherry Mui <cherryyz@google.com>
This adds the nonPGO, non-coverage compiler changes
for the 1.20 release. There's not that much user
visible change.
For #54202.
Change-Id: Ib2964ed5f7e73bb89c720d09b868ab79682f5070
Reviewed-on: https://go-review.googlesource.com/c/go/+/454536
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We're unlikely to get this package out of the door all that soon. For
now add a note that SetFallbackRoots will be most commonly used with
an TBA package, and link the tracking issue.
We could also just remove the "It will most commonly be used ..."
sentence.
Change-Id: Ie96134d757f5b4c69f1878d53c92b5ed602671e4
Reviewed-on: https://go-review.googlesource.com/c/go/+/454056
Reviewed-by: Julie Qiu <julieqiu@google.com>
Run-TryBot: Roland Shoemaker <roland@golang.org>
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For #54202.
For #56548.
Change-Id: If2b9e41813c3e1c8d373469a40e1bd0bd5ea2b16
Reviewed-on: https://go-review.googlesource.com/c/go/+/454595
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
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Reviewed-by: Robert Griesemer <gri@google.com>
This change adds release notes for the "Runtime" section and updated
some of the release notes for runtime/trace and runtime/pprof after I
looked at the full list of runtime-related changes.
For #54202.
Change-Id: Id1395f4e6e02d3fcc248855ca98ad0ee26cae574
Reviewed-on: https://go-review.googlesource.com/c/go/+/454075
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Run-TryBot: Michael Knyszek <mknyszek@google.com>
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Document that a slice can be converted to either an array or a pointer
to an array of a matching underlying array type. This was documented in
the "Conversions from slice to array or array pointer" subsection, but
not in the list of conversion rules.
Updates #46505.
Change-Id: I16a89a63ef23c33580129952415e977a8f334009
Reviewed-on: https://go-review.googlesource.com/c/go/+/452936
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I misunderstood CL 420774. We didn't remove GO_LDSO, just that
make.bash no longer tries to set it automatically. If GO_LDSO is
explicitly set at make.bash, it is still used as the default
dynamic interpreter.
For #54202.
Change-Id: Ided775438b8e4b87a6acd9bc87657657dbd3d91c
Reviewed-on: https://go-review.googlesource.com/c/go/+/453601
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Add code tag for environment variables and file paths in the
Bootstrap section.
Add code tag for packages in the Cgo section.
Change-Id: Ib0fad1c09fbc497a097ef43cbf5850a27b9a6532
Reviewed-on: https://go-review.googlesource.com/c/go/+/453621
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Finish all standard library TODOs, including additions
flagged by another run of relnote.
Change-Id: Ib9d22672b13b9775a98262d645aaf1d54e7494df
Reviewed-on: https://go-review.googlesource.com/c/go/+/453295
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Change-Id: I7e2519601bfe1a59a48e240ff67868b1d74d55d1
Reviewed-on: https://go-review.googlesource.com/c/go/+/453516
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Auto-Submit: Brad Fitzpatrick <bradfitz@golang.org>
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Address the release notes TODO regarding the timeformat analyzer.
Change-Id: Ic132569d84d6e00eeed4ea49f2467e09af4b0756
Reviewed-on: https://go-review.googlesource.com/c/go/+/452915
Run-TryBot: Tim King <taking@google.com>
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If needed, the built-in function append allocates a new underlying
array. While we (probably) don't want to specify exactly how much
is allocated (the prose is deliberately vague), if there's more
space allocated than needed (cap > len after allocation), that
extra space is zeroed. Use an explicit link to the section on
Allocation which explicitly states that newly allocated memory
is zeroed.
Fixes#56684.
Change-Id: I9805d37c263b87860ea703ad143f738a0846247e
Reviewed-on: https://go-review.googlesource.com/c/go/+/452619
Reviewed-by: Ian Lance Taylor <iant@google.com>
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At parse time we don't know if a[i] is an index expression or a
type (or function) instantiation. Because instantiations accept
a list of type arguments, and argument lists permit a trailing
comma, a[i,] is either an instantiation or index expression.
Document that a trailing comma is permitted in the syntax for
index expressions.
For comparison, the same problem arises with conversions which
cannot be distinguished from function calls at parse time. The
spec also permits a trailing comma for conversions T(x,). The
grammar adjustment is the same (see line 5239).
Fixes#55007.
Change-Id: Ib9101efe52031589eb95a428cc6dff940d939f9e
Reviewed-on: https://go-review.googlesource.com/c/go/+/452618
Reviewed-by: Ian Lance Taylor <iant@google.com>
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This change is being made late in the release cycle.
Disable it by default. Insecure path checks may be enabled by setting
GODEBUG=tarinsecurepath=0 or GODEBUG=zipinsecurepath=0.
We can enable this by default in Go 1.21 after publicizing the change
more broadly and giving users a chance to adapt to the change.
For #55356.
Change-Id: I549298b3c85d6c8c7fd607c41de1073083f79b1d
Reviewed-on: https://go-review.googlesource.com/c/go/+/452616
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Run-TryBot: Damien Neil <dneil@google.com>
