5c84441d88
The old algorithm operated on a dependency graph that included all objects (including functions) for simplicity: it was based directly on the dependencies collected for each object during type checking an object's initialization expression. It also used that graph to compute the objects involved in an erroneous initialization cycle. Cycles that consist only of (mutually recursive) functions are permitted in initialization code; so those cycles were silently ignored if encountered. However, such cycles still inflated the number of dependencies a variable might have (due to the cycle), which in some cases lead to the wrong variable being scheduled for initialization before the one with the inflated dependency count. Correcting for the cycle when it is found is too late since at that point another variable may have already been scheduled. The new algorithm computes the initialization dependency graph as before but adds an extra pass during which functions are eliminated from the graph (and their dependencies are "back-propagated"). This eliminates the problem of cycles only involving functions (there are no functions). When a cycle is found, the new code computes the cycle path from the original object dependencies so it can still include functions on the path as before, for the same detailed error message. The new code also more clearly distinguishes between objects that can be in the dependency graph (constants, variables, functions), and objects that cannot, by introducing the dependency type, a new subtype of Object. As a consequence, the dependency graph is smaller. Fixes #10709. Change-Id: Ib58d6ea65cfb279041a0286a2c8e865f11d244eb Reviewed-on: https://go-review.googlesource.com/24131 Reviewed-by: Alan Donovan <adonovan@google.com> |
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README.md
The Go Programming Language
Go is an open source programming language that makes it easy to build simple, reliable, and efficient software.
For documentation about how to install and use Go, visit https://golang.org/ or load doc/install-source.html in your web browser.
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.
Go is the work of hundreds of contributors. We appreciate your help!
To contribute, please read the contribution guidelines: https://golang.org/doc/contribute.html
Note that we do not accept pull requests and that we use the issue tracker for bug reports and proposals only. Please ask questions on https://forum.golangbridge.org or https://groups.google.com/forum/#!forum/golang-nuts.
Unless otherwise noted, the Go source files are distributed under the BSD-style license found in the LICENSE file.
--
Binary Distribution Notes
If you have just untarred a binary Go distribution, you need to set the environment variable $GOROOT to the full path of the go directory (the one containing this file). You can omit the variable if you unpack it into /usr/local/go, or if you rebuild from sources by running all.bash (see doc/install-source.html). You should also add the Go binary directory $GOROOT/bin to your shell's path.
For example, if you extracted the tar file into $HOME/go, you might put the following in your .profile:
export GOROOT=$HOME/go
export PATH=$PATH:$GOROOT/bin
See https://golang.org/doc/install or doc/install.html for more details.