| commit | 90fe4a73fff10394097e21085a9c0c369c61b09a | [log] [tgz] |
|---|---|---|
| author | Robert Griesemer <gri@golang.org> | Wed Oct 23 16:44:51 2019 -0700 |
| committer | Dmitri Shuralyov <dmitshur@golang.org> | Wed May 27 22:53:26 2020 +0000 |
| tree | cc601ce584e4b7a2dec82a685cc543f700873810 | |
| parent | 7f1ef49347e6e1f5a51c9ca3e4f4f617c2317042 [diff] |
[release-branch.go1.13] math/big: make Rat.Denom side-effect free A Rat is represented via a quotient a/b where a and b are Int values. To make it possible to use an uninitialized Rat value (with a and b uninitialized and thus == 0), the implementation treats a 0 denominator as 1. Rat.Num and Rat.Denom return pointers to these values a and b. Because b may be 0, Rat.Denom used to first initialize it to 1 and thus produce an undesirable side-effect (by changing the Rat's denominator). This CL changes Denom to return a new (not shared) *Int with value 1 in the rare case where the Rat was not initialized. This eliminates the side effect and returns the correct denominator value. While this is changing behavior of the API, the impact should now be minor because together with (prior) CL https://golang.org/cl/202997, which initializes Rats ASAP, Denom is unlikely used to access the denominator of an uninitialized (and thus 0) Rat. Any operation that will somehow set a Rat value will ensure that the denominator is not 0. Fixes #36689. For #33792. For #3521. Change-Id: I0bf15ac60513cf52162bfb62440817ba36f0c3fc Reviewed-on: https://go-review.googlesource.com/c/go/+/203059 Run-TryBot: Robert Griesemer <gri@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org> Reviewed-on: https://go-review.googlesource.com/c/go/+/233323 Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com> Run-TryBot: Dmitri Shuralyov <dmitshur@golang.org>
Go is an open source programming language that makes it easy to build simple, reliable, and efficient software.
Gopher image by Renee French, licensed under Creative Commons 3.0 Attributions license.
Our canonical Git repository is located at https://go.googlesource.com/go. There is a mirror of the repository at https://github.com/golang/go.
Unless otherwise noted, the Go source files are distributed under the BSD-style license found in the LICENSE file.
Official binary distributions are available at https://golang.org/dl/.
After downloading a binary release, visit https://golang.org/doc/install or load doc/install.html in your web browser for installation instructions.
If a binary distribution is not available for your combination of operating system and architecture, visit https://golang.org/doc/install/source or load doc/install-source.html in your web browser for source installation instructions.
Go is the work of thousands of contributors. We appreciate your help!
To contribute, please read the contribution guidelines: https://golang.org/doc/contribute.html
Note that the Go project uses the issue tracker for bug reports and proposals only. See https://golang.org/wiki/Questions for a list of places to ask questions about the Go language.