Earlier in the development of the new tracer, m.id was used as a the
canonical ID for threads. Later, we switched to m.procid because it
matches the underlying OS resource. However, in that switch, we missed a
spot.
The tracer catches and emits statuses for goroutines that have remained
in either waiting or syscall across a whole generation, and emits a
thread ID for the latter set. The ID being used here, however, was m.id
instead of m.procid, like the rest of the tracer.
This CL also adds a regression test. In order to make the regression
test actually catch the failure, we also have to make the parser a
little less lenient about GoStatus events with GoSyscall: if this isn't
the first generation, then we should've seen the goroutine bound to an
M already when its status is getting emitted for its context. If we emit
the wrong ID, then we'll catch the issue when we emit the right ID when
the goroutine exits the syscall.
Fixes#65196.
Change-Id: I78b64fbea65308de5e1291c478a082a732a8bf9f
Reviewed-on: https://go-review.googlesource.com/c/go/+/557456
Reviewed-by: Michael Pratt <mpratt@google.com>
Auto-Submit: Michael Knyszek <mknyszek@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
The pgo compilation time is very long if the profile file is large.
We added a preprocess tool to pre-parse profile file in order to
expedite the compile time.
Change-Id: I6f50bbd01f242448e2463607a9b63483c6ca9a12
Reviewed-on: https://go-review.googlesource.com/c/go/+/529738
Reviewed-by: Michael Pratt <mpratt@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
In CL 557177, I attempted to fix a logical race in this test (#65175).
However, I introduced a data race in the process (#65209).
The race was reported on the windows-amd64-race builder. When I tried
to reproduce it on linux/amd64, I added a time.Sleep in the Accept
loop. However, that Sleep causes the test to fail outright with
EADDRINUSE, which suggests that my earlier guess about the open Conn
preventing reuse of the port was, in fact, incorrect.
On some platforms we could instead use SO_REUSEPORT and avoid closing
the first Listener entirely, but that wouldn't be even remotely in the
spirit of the original test.
Since I don't see a way to preserve the test in a way that is not
inherently flaky / racy, I suggest that we just delete it. It was
originally added as a regression test for a bug in the nacl port,
which no longer exists anyway. (Some of that code may live on in the
wasm port, but it doesn't seem worth maintaining a flaky
port-independent test to maintain a regression test for a bug specific
to secondary platforms.)
Fixes#65209.
Updates #65175.
Change-Id: I32f9da779d24f2e133571f0971ec460cebe7820a
Cq-Include-Trybots: luci.golang.try:gotip-windows-amd64-race
Reviewed-on: https://go-review.googlesource.com/c/go/+/557536
Run-TryBot: Bryan Mills <bcmills@google.com>
Auto-Submit: Bryan Mills <bcmills@google.com>
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Reviewed-by: Jonathan Amsterdam <jba@google.com>
Fixes a couple of misalignments with RFC 5322 which introduce
significant diffs between (mostly) conformant parsers.
This change reverts the changes made in CL50911, which allowed certain
special RFC 5322 characters to appear unquoted in the "phrase" syntax.
It is unclear why this change was made in the first place, and created
a divergence from comformant parsers. In particular this resulted in
treating comments in display names incorrectly.
Additionally properly handle trailing malformed comments in the group
syntax.
Fixes#65083
Change-Id: I00dddc044c6ae3381154e43236632604c390f672
Reviewed-on: https://go-review.googlesource.com/c/go/+/555596
Reviewed-by: Damien Neil <dneil@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Currently, freedefer's API forces a subtle and fragile situation. It
requires that the caller unlink the _defer from the G list, but
freedefer itself is responsible for zeroing some _defer fields. In the
window between these two steps, we have to prevent stack growth
because stack growth walks the defer list (which no longer contains
the unlinked defer) to adjust pointers, and would thus leave an
unadjusted and potentially invalid pointer behind in the _defer before
freedefer zeroes it.
This setup puts part of this subtle responsibility on the caller and
also means freedefer must be nosplit, which forces other shenanigans
to avoid nosplit overflows.
We can simplify all of this by replacing freedefer with a new popDefer
function that's responsible for both unlinking and zeroing the _defer,
in addition to freeing it.
Some history: prior to regabi, defer records contained their argument
frame, which deferreturn copied to the stack before freeing the defer
record (and subsequently running the defer). Since that argument frame
didn't have a valid stack map until we ran the deferred function, the
non-preemptible window was much larger and more difficult to isolate.
Now we use normal closure calls to capture defer state and call the
defer, so the non-preemptible window is narrowed to just the unlinking
step.
Change-Id: I7cf95ba18e1e2e7d73f616b9ed9fb38f5e725d72
Reviewed-on: https://go-review.googlesource.com/c/go/+/553696
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Auto-Submit: Austin Clements <austin@google.com>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
The Go 1.23 development tree has opened. This is a time to update
all golang.org/x/... module versions that contribute packages to the
std and cmd modules in the standard library to latest master versions.
Generated with:
go install golang.org/x/build/cmd/updatestd@latest
go install golang.org/x/tools/cmd/bundle@latest
updatestd -goroot=$(pwd) -branch=master
For #36905.
Change-Id: I46a68f27a54f1e3f9e1aa5af4de6ee0b26388f3f
Reviewed-on: https://go-review.googlesource.com/c/go/+/557457
Reviewed-by: Carlos Amedee <carlos@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Add files to doc/initial that set up the overall structure
of the release notes document.
For #64169.
Change-Id: Ifbf330e554e1fa20d47c72cc309d5cd26048a323
Reviewed-on: https://go-review.googlesource.com/c/go/+/556817
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
This is the first CL in a sequence that adds support
for generating release notes from fragments.
The actual generator will live elsewhere, in x/build.
This repo will hold the content and some validity
checks.
For #64169.
Change-Id: Iaa8d9ad96393ab9433170b3cfa47334837f3f691
Reviewed-on: https://go-review.googlesource.com/c/go/+/542515
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
winmm.dll is only used for timeBeginPeriod and timeEndPeriod, which are
not needed on Windows versions supporting high resolution timers, that
is Windows 10 version 1803, and later.
Updates #56745.
Change-Id: Ie9576638fb8d2b4e648283bec3170aefa76f9f82
Reviewed-on: https://go-review.googlesource.com/c/go/+/556935
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Bryan Mills <bcmills@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
For #61422
Change-Id: I50e427b78a533c3196aeb5291a34c05528ee0bed
Reviewed-on: https://go-review.googlesource.com/c/go/+/557455
Reviewed-by: Cherry Mui <cherryyz@google.com>
Auto-Submit: Carlos Amedee <carlos@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Also make it flakier in longtest mode by burning through more
ephemeral ports. (Burning through the ports raised the failure rate
for me locally enough to reliably reproduce the failure in #65175 with
-count=10.)
Fixes#65175 (I hope).
Change-Id: I5f5b68b6bf6a6aa92e66f0288078817041656a3e
Reviewed-on: https://go-review.googlesource.com/c/go/+/557177
Reviewed-by: Damien Neil <dneil@google.com>
Auto-Submit: Bryan Mills <bcmills@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
The typeparams.IndexExpr wrapper type was added as a compatibility layer
to make the go/types code symmetric with types2. However, this type
incidentally implemented the ast.Expr interface, leading to the
accidental misuse that led to golang/go#63933.
Fix this minimally for now, though leave a TODO that this old
compatibility shim really needs to be eliminated.
Also fix a case in types2 where operand.expr was set to a typed nil.
Fixesgolang/go#63933
Change-Id: I180d411e52f795a8322ecce6ed8649e88af1c63b
Reviewed-on: https://go-review.googlesource.com/c/go/+/554395
Reviewed-by: Robert Griesemer <gri@google.com>
Auto-Submit: Robert Findley <rfindley@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
The test is skipped on wasm platforms for now, because it
successfully detects a starvation bug on those platforms.
For #65178.
Change-Id: I05d28f1c7be99fcab67ec4dfaa38f412e11fd3cb
Reviewed-on: https://go-review.googlesource.com/c/go/+/557038
Auto-Submit: Bryan Mills <bcmills@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Damien Neil <dneil@google.com>
I added this map in CL 526117, but it is apparently unused.
I assume that I removed all uses of it while revising that change.
Updates #59718.
Updates #50216.
Change-Id: I8cdac39f4764d1fcc31566408304c850cf0f9374
Reviewed-on: https://go-review.googlesource.com/c/go/+/557176
Auto-Submit: Bryan Mills <bcmills@google.com>
Reviewed-by: Damien Neil <dneil@google.com>
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Currently the new execution tracer's handling of CPU profile samples is
very best-effort. The same CPU profile buffer is used across
generations, leading to a high probability that CPU samples will bleed
across generations. Also, because the CPU profile buffer (not the trace
buffer the samples get written into) isn't guaranteed to be flushed when
we close out a generation, nor when tracing stops. This has led to test
failures, but can more generally just lead to lost samples.
In general, lost samples are considered OK. The CPU profile buffer is
only read from every 100 ms, so if it fills up too much before then, old
samples will get overwritten. The tests already account for this, and in
that sense the CPU profile samples are already best-effort. But with
actual CPU profiles, this is really the only condition under which
samples are dropped.
This CL aims to align CPU profiles better with traces by eliminating
all best-effort parts of the implementation aside from the possibility
of dropped samples from a full buffer.
To achieve this, this CL adds a second CPU profile buffer and has the
SIGPROF handler pick which CPU profile buffer to use based on the
generation, much like every other part of the tracer. The SIGPROF
handler then reads the trace generation, but not before ensuring it
can't change: it grabs its own thread's trace seqlock. It's possible
that a SIGPROF signal lands while this seqlock is already held by the
thread. Luckily this is detectable and the SIGPROF handler can simply
elide the locking if this happens (the tracer will already wait until
all threads exit their seqlock critical section).
Now that there are two CPU profile buffers written to, the read side
needs to change. Instead of calling traceAcquire/traceRelease for every
single CPU sample event, the trace CPU profile reader goroutine holds
this conceptual lock over the entirety of flushing a buffer. This means
it can pick the CPU profile buffer for the current generation to flush.
With all this machinery in place, we're now at a point where all CPU
profile samples get divided into either the previous generation or the
current generation. This is good, since it means that we're able to
emit profile samples into the correct generation, avoiding surprises in
the final trace. All that's missing is to flush the CPU profile buffer
from the previous generation, once the runtime has moved on from that
generation. That is, when the generation counter updates, there may yet
be CPU profile samples sitting in the last generation's buffer. So,
traceCPUFlush now first flushes the CPU profile buffer, followed by any
trace buffers containing CPU profile samples.
The end result of all this is that no sample gets left behind unless it
gets overwritten in the CPU profile buffer in the first place. CPU
profile samples in the trace will now also get attributed to the right
generation, since the SIGPROF handler now participates in the tracer's
synchronization across trace generations.
Fixes#55317.
Change-Id: I47719fad164c544eef0bb12f99c8f3c15358e344
Reviewed-on: https://go-review.googlesource.com/c/go/+/555495
Auto-Submit: Michael Knyszek <mknyszek@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
This was an oversight in porting over cmd/trace to the new trace format
and API.
Fixes#65153.
Change-Id: I883d302f95956fcc9abb60aa53165acb6d099d67
Reviewed-on: https://go-review.googlesource.com/c/go/+/557175
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
(The corresponding update for the last release cycle was CL 510735.)
For #40705
For #64340
Change-Id: I123ce68131a6c7b0344cab54cd29402cabb57225
Reviewed-on: https://go-review.googlesource.com/c/go/+/557155
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
This works around an apparent bug in the Git HTTP backend, introduced
in Git 2.21, that causes responses for the version 1 protocol to
provide incomplete tags.
For Git commands older than 2.18, this configuration flag is ignored.
(Note that Git 2.29 and above already use protocol version 2 by
default.)
Fixes#56881.
Change-Id: I9b241cfb604e5f633ca6a5d799df6706246684a7
Cq-Include-Trybots: luci.golang.try:gotip-linux-amd64-longtest,gotip-windows-amd64-longtest
Reviewed-on: https://go-review.googlesource.com/c/go/+/556358
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Reviewed-by: Michael Matloob <matloob@golang.org>
Add missing checks for the case where the range expression is
a (possibly untyped) constant integer expression.
Add context parameter to assignVar for better error message
where the expression is part of a range clause.
Also, rename s/expr/Expr/ where it denotes an AST expression,
for clarity.
Fixes#65133.
For #65137.
Change-Id: I72962d76741abe79f613e251f7b060e99261d3ae
Reviewed-on: https://go-review.googlesource.com/c/go/+/556398
Run-TryBot: Robert Griesemer <gri@google.com>
Auto-Submit: Robert Griesemer <gri@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>
Reviewed-by: Robert Griesemer <gri@google.com>
For #61422
Change-Id: Ide818366b035eada4ba04b70b4741fb1891585d6
Reviewed-on: https://go-review.googlesource.com/c/go/+/556396
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Carlos Amedee <carlos@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Auto-Submit: Damien Neil <dneil@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Very occasionally, at least on linux/386, strace itself will crash in
TestUsingVDSO. Detect these crashes and just skip the test.
Fixes#63734.
Change-Id: I050494459d47dd96c0b8dc0b16353cb532fba93e
Reviewed-on: https://go-review.googlesource.com/c/go/+/556357
Auto-Submit: Austin Clements <austin@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
This test exercises the SIGQUIT crash loop and managed to trigger the
race from #65138 at least once.
For #65138.
Fixes#64752.
Change-Id: I11091510aa7ae4f58b1d748e53df2e3e3dbfb323
Reviewed-on: https://go-review.googlesource.com/c/go/+/556356
Auto-Submit: Michael Pratt <mpratt@google.com>
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Reviewed-by: Cherry Mui <cherryyz@google.com>
types2.Unalias is not needed if we know we have a core or underlying
type. Also, types of declared functions (signatures) cannot be aliases
(this includes tuples).
Fixes#65125.
Change-Id: I1faa26b66f6c646719e830dd661136fae86f3775
Reviewed-on: https://go-review.googlesource.com/c/go/+/556036
Run-TryBot: Robert Griesemer <gri@google.com>
Reviewed-by: Mauri de Souza Meneguzzo <mauri870@gmail.com>
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Auto-Submit: Robert Griesemer <gri@google.com>
Reviewed-by: Robert Griesemer <gri@google.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Add godoc links from io/fs to testing/fstest for discoverability.
Change-Id: I6550b4b703d2214faa732987ec8630ac903705b5
Reviewed-on: https://go-review.googlesource.com/c/go/+/534095
Reviewed-by: Michael Knyszek <mknyszek@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Bryan Mills <bcmills@google.com>
This addresses some panics (out of bounds slice accesses and nil pointer
dereferences) when parsing malformed data. These were found via light
fuzzing, not by any rigorous means, and more potential panics probably
exist.
Fixes#64878.
Fixes#64879.
Change-Id: I4085788ba7dc91fec62e4abd88f50777577db42f
Reviewed-on: https://go-review.googlesource.com/c/go/+/552995
Auto-Submit: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
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Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Now, this is embarrassing. For the whole Go 1.20 and Go 1.21 cycles, we
based RSA public key operation (verification and decryption) benchmarks
on the keys in rsa_test.go, which had E = 3. Most keys in use, including
all those generated by GenerateKey, have E = 65537. This significantly
skewed even relative benchmarks, because the new constant-time
algorithms would incur a larger slowdown for larger exponents.
I noticed this only because I got a production profile for an
application that does a lot of RSA verifications, saw ExpShort show up,
made ExpShort faster, and the crypto/rsa profiles didn't move.
We were measuring the wrong thing, and the slowdown was worse than we
thought. My apologies.
(If E had not been parametrized, it would have avoided issues like this
one, too. Grumble. https://words.filippo.io/parameters/#fn9)
goos: darwin
goarch: arm64
pkg: crypto/rsa
│ g35222eeb78 │ new │
│ sec/op │ sec/op vs base │
DecryptPKCS1v15/2048-8 1.414m ± 2% 1.417m ± 1% ~ (p=0.971 n=10)
DecryptPKCS1v15/3072-8 4.107m ± 0% 4.160m ± 1% +1.29% (p=0.000 n=10)
DecryptPKCS1v15/4096-8 9.363m ± 1% 9.305m ± 1% ~ (p=0.143 n=10)
EncryptPKCS1v15/2048-8 162.8µ ± 2% 212.1µ ± 0% +30.34% (p=0.000 n=10)
DecryptOAEP/2048-8 1.460m ± 4% 1.413m ± 1% ~ (p=0.105 n=10)
EncryptOAEP/2048-8 161.7µ ± 0% 213.4µ ± 0% +31.99% (p=0.000 n=10)
SignPKCS1v15/2048-8 1.419m ± 1% 1.476m ± 1% +4.05% (p=0.000 n=10)
VerifyPKCS1v15/2048-8 160.6µ ± 0% 212.6µ ± 3% +32.38% (p=0.000 n=10)
SignPSS/2048-8 1.419m ± 0% 1.477m ± 2% +4.07% (p=0.000 n=10)
VerifyPSS/2048-8 163.9µ ± 8% 212.3µ ± 0% +29.50% (p=0.000 n=10)
geomean 802.5µ 899.1µ +12.04%
Updates #63516
Change-Id: Iab4a0684d8101ae07dac8462908d8058fe5e9f3d
Reviewed-on: https://go-review.googlesource.com/c/go/+/552895
Reviewed-by: Roland Shoemaker <roland@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Than McIntosh <thanm@google.com>
CL 555355 has a bug in it - the GC program flag was also used to decide
when to free the unrolled bitmap. After that CL, we just don't free any
unrolled bitmaps, leading to a memory leak.
Use a separate flag to track types that need to be freed when their
corresponding object is freed.
Change-Id: I841b65492561f5b5e1853875fbd8e8a872205a84
Reviewed-on: https://go-review.googlesource.com/c/go/+/555416
Auto-Submit: Keith Randall <khr@google.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Keith Randall <khr@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Accurate position information for embedded types in interfaces is
crucial to identify the corresponding source file, and with that
the Go language version associated with that file. (The position
information is also important for proper error messages.)
Before this CL, the position information for embedded types was
discarded after type set computation, in the assumption that it
was not needed anymore. However, substitutions that update the
interface may lead to repeated type set computations which then
won't have the correct position information.
This CL does preserve the position information for embedded
types until the end of type checking (cleanup phase), and also
copy the position information during a substitution of the
interface.
The respective bug (#64759) doesn't seem to appear in 1.22 (most
likely because it's hidden by some of the changes made with respect
to the file version logic), but the existing code is still wrong.
The backport of this code to 1.21 and 1.20 fixes the issue in those
releases.
For #64759.
Change-Id: I80f4004c9d79cb02eac6739c324c477706615102
Reviewed-on: https://go-review.googlesource.com/c/go/+/555296
Run-TryBot: Robert Griesemer <gri@google.com>
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Reviewed-by: Robert Griesemer <gri@google.com>
It doesn't have a GC program - the whole point is that it is
the unrolled version of a GC program.
Fortunately, this isn't a bug as (*mspan).typePointersOfUnchecked
ignores the GCProg flag and just uses GCData as a bitmap unconditionally.
Change-Id: I2508af85af4a1806946e54c893120c5cc0cc3da3
Reviewed-on: https://go-review.googlesource.com/c/go/+/555355
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Reviewed-by: Keith Randall <khr@google.com>
Per https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html:
“If, when attempting to write a file, the destination directory is
non-existent an attempt should be made to create it with permission
0700. […] The application should be prepared to handle the case where
the file could not be written […]. In such case it may choose to
present an error message to the user.”
In certain CI environments, these directories have well-defined
locations but do not exist and cannot be created. In that case,
we now choose to log and return from the test without failing it.
To prevent the functions from falling back to being entirely untested,
we still fail the test (and “present an error message to the user”) if
either function returns an empty string without an error, or returns a
path that refers to a non-directory or results in an error other than
ErrNotExist.
In addition, since the tests themselves no longer create subdirectories,
we add examples illustrating the suggested pattern of usage.
Fixes#64990.
Change-Id: Ie72106424f5ebe36eaf9288c22710d74bb14a462
Reviewed-on: https://go-review.googlesource.com/c/go/+/554815
Reviewed-by: Austin Clements <austin@google.com>
Run-TryBot: Bryan Mills <bcmills@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Bryan Mills <bcmills@google.com>
Shape-based stenciling in the Go compiler's generic instantiation
phase looks up shape types using the underlying type of a given target
type. This has a beneficial effect in most cases (e.g. we can use the
same shape type for two different named types whose underlying type is
"int"), but causes some problems when the underlying type is a very
large structure. The link string for the underlying type of a large
imported struct can be extremely long, since the link string
essentially enumerates the full package path for every field type;
this can produce a "go.shape.struct { ... " symbol name that is
absurdly long.
This patch switches the compiler to use a hash of the underlying type
link string instead of the string itself, which should continue to
provide commoning but keep symbol name lengths reasonable for shape
types based on large imported structs.
Fixes#65030.
Change-Id: I87d602626c43172beb99c186b8ef72327b8227a2
Reviewed-on: https://go-review.googlesource.com/c/go/+/554975
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Than McIntosh <thanm@google.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
CL 549536 intended to decouple the internal implementation of rwmutex
from the semantic meaning of an rwmutex read/write lock in the static
lock ranking.
Unfortunately, it was not thought through well enough. The internals
were represented with the rwmutexR and rwmutexW lock ranks. The idea was
that the internal lock ranks need not model the higher-level ordering,
since those have separate rankings. That is incorrect; rwmutexW is held
for the duration of a write lock, so it must be ranked before any lock
taken while any write lock is held, which is precisely what we were
trying to avoid.
This is visible in violations like:
0 : execW 11 0x0
1 : rwmutexW 51 0x111d9c8
2 : fin 30 0x111d3a0
fatal error: lock ordering problem
execW < fin is modeled, but rwmutexW < fin is missing.
Fix this by eliminating the rwmutexR/W lock ranks shared across
different types of rwmutex. Instead require users to define an
additional "internal" lock rank to represent the implementation details
of rwmutex.rLock. We can avoid an additional "internal" lock rank for
rwmutex.wLock because the existing writeRank has the same semantics for
semantic and internal locking. i.e., writeRank is held for the duration
of a write lock, which is exactly how rwmutex.wLock is used, so we can
use writeRank directly on wLock.
For #64722.
Cq-Include-Trybots: luci.golang.try:gotip-linux-amd64-staticlockranking
Change-Id: Ia572de188a46ba8fe054ae28537648beaa16b12c
Reviewed-on: https://go-review.googlesource.com/c/go/+/555055
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
