Discussion
The Go Blog
shoo: If I follow, this isn't a compile time inline directive, it's a `go fix` time source transformation of client code calling the annotated function.Per the post, it sounds like this is most effective in closed-ecosystem internal monorepo-like contexts where an organisation has control over every instance of client code & can `go fix` all of the call sites to completely eradicate all usage of a deprecated APIs:> For many years now, our Google colleagues on the teams supporting Java, Kotlin, and C++ have been using source-level inliner tools like this. To date, these tools have eliminated millions of calls to deprecated functions in Google’s code base. Users simply add the directives, and wait. During the night, robots quietly prepare, test, and submit batches of code changes across a monorepo of billions of lines of code. If all goes well, by the morning the old code is no longer in use and can be safely deleted. Go’s inliner is a relative newcomer, but it has already been used to prepare more than 18,000 changelists to Google’s monorepo.It could still have some incremental benefit for public APIs where client code is not under centralised control, but would not allow deprecated APIs to be removed without breakage.
tapirl: It looks the following code will be rewritten badly, but no ways to avoid it? package main //go:fix inline func handle() { recover() } func foo() { handle() } func main() { defer foo() panic("bye") }
arccy: Or: your buggy code is no longer buggy.
omoikane: I wonder why they chose to add these directives as comments as opposed to adding new syntax for them. It feels like a kludge.https://wiki.c2.com/?HotComments
0x696C6961: The //go:xyz comments are an established pattern in the Go tooling.
kjksf: Go designers distinguish between Go language as defined by Go spec and implementation details.//go:fix is something understood by a particular implementation of Go. Another implementation could implement Go without implementing support for //go:fix and it would be a fully compliant implementation of Go, the language.If they made it part of the syntax, that would require other implementations to implement it.
bheadmaster: That's such an elegant solution.I keep being impressed at subtle but meaningful things that Go does right.
Mond_: This is begging the question. Yes, but why did they do that over dedicated syntax?(My personal theory is that early go had a somewhat misguided idea of simplicity, and preferred overloading existing concepts with special cases over introducing new keywords. Capitalization for visibility is another example of that.)
tapirl: You claim listens right for this specified example. :DIt is just a demo.
thwarted: //go:xyz is dedicated syntax that is compatible with both the language spec and other toolchains that don't know about it.
dwattttt: If the comments impact correctness (which inlining doesn't, but I believe there are other directives that do), saying it's "an implementation detail" waves away "it's an implementation detail that everyone needs" aka part of the spec.The reason it feels like a kludge is that "comments" are normally understood to be non-impactful. Is a source transformation that removes all comments valid? If comments have no impact per the spec, yes. But that's not the case here.In practice comments in go are defined to be able to carry semantic meaning extensibly. Whether they're safe to ignore depends on what meaning is given to the directives, e.g. conditional compilation directives.
