semaphore: panic on negative weights

The semaphore.Weighted API accepts int64 for weights. If a negative
weight is passed, it mathematically corrupts the internal state tracker
(s.cur) and bypasses the package's existing safety checks.

This adds strict boundary validation to panic immediately if a negative
weight is provided.

Fixes golang/go#80183

Change-Id: I7e74bad404a8b99aef7e3d2189dda43f8ea644c2
GitHub-Last-Rev: ee6289c
GitHub-Pull-Request: #31
Reviewed-on: https://go-review.googlesource.com/c/sync/+/796080
Reviewed-by: Damien Neil <dneil@google.com>
Reviewed-by: Zain Yousef <zain.19dj@gmail.com>
Reviewed-by: Alan Donovan <adonovan@google.com>
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all: fix some comments to improve readability

Change-Id: If88a7d731009bfb40774ea45a94187ce4d0db848
Reviewed-on: https://go-review.googlesource.com/c/sync/+/785081
Reviewed-by: Mark Freeman <markfreeman@google.com>
Auto-Submit: Alan Donovan <adonovan@google.com>
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Reviewed-by: Alan Donovan <adonovan@google.com>

errgroup: fix a typo in the documentation

Change-Id: I265cbc977e15a81c0068e7b60933843d8f02fe6a
Reviewed-on: https://go-review.googlesource.com/c/sync/+/747140
Reviewed-by: Alan Donovan <adonovan@google.com>
Auto-Submit: Alan Donovan <adonovan@google.com>
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Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>

errgroup: use consistent read for SetLimit panic

This could produce a confusing panic message if the second len(g.sem)
call returns 0. Avoid that by reading it once.

Change-Id: Ibdb4963f90921bc20427b3f1e2de410638f6cb6b
Reviewed-on: https://go-review.googlesource.com/c/sync/+/726280
Reviewed-by: Alan Donovan <adonovan@google.com>
Auto-Submit: Alan Donovan <adonovan@google.com>
Reviewed-by: Sean Liao <sean@liao.dev>
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errgroup: fix some typos in comment

Change-Id: I3dd6df0eb2cc592f8811935cbcbca54a0d9304ce
Reviewed-on: https://go-review.googlesource.com/c/sync/+/713400
Reviewed-by: Alan Donovan <adonovan@google.com>
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all: upgrade go directive to at least 1.24.0 [generated]

By now Go 1.25.0 has been released, and Go 1.23 is no longer supported
per the Go Release Policy (see https://go.dev/doc/devel/release#policy).

For golang/go#69095.

[git-generate]
(cd . && go get go@1.24.0 && go mod tidy && go fix ./... && go mod edit -toolchain=none)

Change-Id: Ifa2b9ecc1efe475dfe4d60f41fb3ad2c63896d12
Reviewed-on: https://go-review.googlesource.com/c/sync/+/695358
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
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Reviewed-by: David Chase <drchase@google.com>

errgroup: revert propagation of panics

This change reverts CL 644575, which caused panics in the f()
call after group.Go(f) to be propagated to the subsequent
group.Wait call. This caused more problems than it solved.

Also:
- preserve some of the doc comment wording of Group.Go.
- leave a "tsunami stone" comment in Group.Go.

Fixes golang/go#53757
Updates golang/go#74275
Updates golang/go#74304
Updates golang/go#74306

Change-Id: I6e3992510944db7d69c72eaf241aedf8b84e62dd
Reviewed-on: https://go-review.googlesource.com/c/sync/+/682935
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errgroup: remove duplicated comment

Change-Id: I5cdcc5034ccd87b939a406693e97485553ab60fa
Reviewed-on: https://go-review.googlesource.com/c/sync/+/676715
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Alan Donovan <adonovan@google.com>
Auto-Submit: Alan Donovan <adonovan@google.com>
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errgroup: propagate panic and Goexit through Wait

Recovered panic values are wrapped and saved in Group.
Goexits are detected by a sentinel value set after the given function
returns normally. Wait propagates the first instance of a panic or
Goexit.

According to the runtime.Goexit after the code will not be executed,
with a bool, if f not call runtime.Goexit, is true,
determine whether to propagate runtime.Goexit.

Fixes golang/go#53757

Change-Id: Ic6426fc014fd1c4368ebaceef5b0d6163770a099
Reviewed-on: https://go-review.googlesource.com/c/sync/+/644575
Reviewed-by: Sean Liao <sean@liao.dev>
Auto-Submit: Alan Donovan <adonovan@google.com>
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Reviewed-by: Alan Donovan <adonovan@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
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errgroup: document calling Go before Wait

Fixes golang/go#70284

Change-Id: I31d60ea182226c032b0ffbddcbb5b53675dfd5e6
Reviewed-on: https://go-review.googlesource.com/c/sync/+/660075
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Reviewed-by: Damien Neil <dneil@google.com>