proposal: cmd/go: notify about newer major versions

[zachgersh]

Proposal: Major Module Version Alerts

This is a unification of two separate proposals (#38762 and #38502) that seek to alert users to the fact that a set of new major module versions may be available for inclusion in their project.

Problem

Semantic Import Versioning introduced the concept of a version suffix, which needs to be explicitly specified on your module path for major versions greater than 1. It is easy for users to consume a v0/v1 version of a module by default, even if they would be better served by selecting the most recent major version.

Discoverability is a key issue. The mechanisms for module authors to advertise recent major versions are inconsistent, and can be low-visibility (documentation? README.md?) or highly disruptive (printing deprecation warnings in init, broken builds to force an investigation).

Abstract

We propose a mechanism that notifies users of the latest major version of a module dependency when (a) that dependency is first added to the project; (b) they update to a newer minor or patch version; or (c) they list out dependencies that can be upgraded.

The proposed notification is informational; the user will have to decide the best course of action (stay with the v0/v1 version they fetched, or update their code to use a later version). We understand that automatic upgrades are not generally possible, as new major semantic versions are necessarily incompatible with previous ones.

Proposal

We propose notifying users of new major versions when:

• They first add a requirement for an old major version of a module
• They update a requirement for an old major version of a module
• They list dependencies that can be updated

There are a few ways users add requirements to their modules:

• By running go get github.com/user/repo
• By adding a require github.com/user/repo line to their go.mod file manually
• By adding an import line to a Go source file, and having goimports or gopls editor integration add the import line on save

For the latter two, the module isn't fetched until the go command is invoked within the module.

There are a few ways users update requirements:

• By running go get [-u] github.com/user/repo
• By running go get -u ./... from the module root

And there is one way users find out about available updates:

• By running go list -m -u all

We propose to, in these cases, have the go tool print a note when a more recent major version of the module is available.

Examples

Consider a user fetching github.com/peterbourgon/ff with go get. We propose adding a notification to the output, alerting the user to a new major version:

$ go get github.com/peterbourgon/ff
go: finding github.com/pelletier/go-toml v1.6.0
go: finding gopkg.in/yaml.v2 v2.2.4
go: finding github.com/davecgh/go-spew v1.1.1
go: downloading github.com/peterbourgon/ff v1.7.0
go: extracting github.com/peterbourgon/ff v1.7.0
go: note: a more recent major version is available: github.com/peterbourgon/ff/v3 [v3.1.0]  👈

Consider a user listing all of the most recent versions of their dependencies. We propose printing the same note to standard error after any new minor or patch versions:

$ go list -m -u all
example.com/my-module
github.com/BurntSushi/toml v0.3.1
github.com/mitchellh/go-wordwrap v1.0.0
github.com/peterbourgon/ff v1.6.0 [v1.7.0]
go: note: a more recent major version is available: github.com/peterbourgon/ff/v3 [v3.1.0] 👈

If the requirement is added to the go.mod file manually, the go tool would print the notification when it first fetches the new module, as part of a go build, go test, etc. run.

Integrations

pkg.go.dev

The Go package discovery website at pkg.go.dev shows modules and their versions. However, it obscures successive major versions when they exist, apparently treating major module versions as completely distinct. For example, the landing page for peterbourgon/ff shows v1.7.0 with a "Latest" bubble beside it. The versions tab does list other major versions, but under the heading "Other modules containing this package", which is confusing.
Instead, pkg.go.dev could feature a prominent indicator on the landing page for a v0/v1 module that there are two successive major versions (v2 and v3), to funnel the user toward the latter.

Editor integration (gopls, goimports)

Go text editor integrations typically include a feature that automatically adds import statements to source files based on the mentioned identifiers. Because of Semantic Import Versioning, this also gives those tools the responsibility of choosing the major version of the imported module. In the case where there is no suitable existing requirement in the project’s go.mod file, these editor integrations could alert the user to the availability of newer major module versions. How this works is outside the scope of this proposal.

Proposal Co-authors

• @adg
• @peterbourgon

[bcmills]

The main problem with “on first add” warnings is that users often don't have control over when things are added: it's easy for a tool to accidentally do the thing that triggers the warning (and then not log the warning, because the command completed successfully), and then the warning is buried ~forever. (Compare rust-lang/cargo#5560.)

The editor integration seems more interesting, in that editors have the opportunity to surface low-priority information based on what the user is viewing rather than based on what they are doing.

[adg]

it's easy for a tool to accidentally do the thing that triggers the warning (and then not log the warning, because the command completed successfully), and then the warning is buried ~forever

Do you have a concrete example of this? I just use the go tool to manage my dependencies.

It seems a bit cavalier to dismiss the utility of this proposal just because some people or tools might ignore the output.

[bcmills]

Do you have a concrete example of this?

Consider the following scenarios:

• You run a command that produces a lot of output, such as go test all or go test -v ./..., then go back to editing your code (or go get a coffee or otherwise turn your attention from the go test command). By the time you look at the output (all tests passed!), the warning has scrolled well off the screen.

• You receive a pull request from an external user who copied the change from a local patch, and didn't feel like rewriting their patch (or even mentioning the newer version) when they mailed you the change.

• You added an import to a file, and now gopls is suggesting a change to your go.mod file to add the corresponding module (perhaps based on an internal, background go mod tidy run). You add it.

In all of these cases, the warning appeared at some point but was either ignored or missed entirely.

If it is important to surface out-of-date dependencies, I don't think a one-time warning is a good way to do that because it's so easy to miss the one time it appears. (Or, to put it another way: if it's unimportant enough that we shouldn't worry about the user missing the warning, then it's probably not important enough to emit the warning in the first place.)

[bcmills]

CC @jayconrod @matloob

[peterbourgon]

These proposals aren't intended to be perfect or exhaustive solutions to the complex problems they address — they're intended to be (substantial) improvements to the status quo. It is of course possible that a user could add a new module dependency to their project and then run the go tool in such a way that it would be easy to miss the messages we're proposing to add. YMMV, but I think it is much more likely, and far more common, that users add dependencies deliberately, and do pay attention to the results of the fetch.

[myitcv]

YMMV, but I think it is much more likely, and far more common, that users add dependencies deliberately, and do pay attention to the results of the fetch.

I commented over in #40357 (comment). I suspect in these days of gopls that the goimports-esque workflow is actually the most common.

Hence:

The editor integration seems more interesting, in that editors have the opportunity to surface low-priority information based on what the user is viewing rather than based on what they are doing.

is I think the best way to surface this information.

It seems a bit cavalier to dismiss the utility of this proposal just because some people or tools might ignore the output

@adg - I don't think this is a fair or particularly charitable interpretation of @bcmills' response. @bcmills made an observation about the problems associated with “on first add” warnings, cited an example, and then went on to agree with the proposal in the context of surfacing this via editor integrations. I don't think I would characterise that as "dismiss(ing) the utility of this proposal".

As some context, the golang-tools group has been discussing problems/solutions such as this since GopherCon 2018 (the group was largely established in the wake of the vgo release). I might well be biased, but based on previous experience the monthly calls are a good opportunity for discussion of these problems/solutions/options in the pre-proposal (design) phase.

[jayconrod]

This overlaps a bit with #40357, but I assume if a module author explicitly deprecates a major version with a comment in go.mod, then the go command wouldn't also show this notice.

I think some signal from the module author should be required to show a notice though, for two reasons:

1. If a new major version is available, it doesn't necessarily mean the old major version is deprecated. Even if no new features are added, an old major version may still receive bug fixes and security updates. Users might still depend on features in the old version that were removed. Basically, migrating to a new major version isn't necessarily the right choice for users. While the messages proposed here don't suggest an action, I feel like they imply that.
2. If we're telling users about a new major version, we should provide an action they can take to migrate. Because major versions are incompatible changes, there's nothing we can do automatically, yet. It would be better for the author to provide migration instructions in a deprecation notice. Or ideally, if migrations were automated (cmd/fix: automate migrations for simple deprecations #32816), we could tell people what command to run.

[peterbourgon]

I think some signal from the module author should be required to show a notice

The problem we're trying to solve is package consumers who intend to take the latest major version of a module, but select an old version due to unfamiliarity with the nuances of SIV. Making package authors opt-in to this notification wold subvert the intent and impact of the proposal.

If a new major version is available, it doesn't necessarily mean the old major version is deprecated.

The notification that a new major version is available is in no way a signal of deprecation of the current version. There is another proposal for authors who want to opt in to that stronger messaging.

If we're telling users about a new major version, we should provide an action they can take to migrate.

We initially had the notification include a command to make the upgrade, but went with this version in the end. Happy to switch back if that's the consensus.

[icholy]

If a new major version is available, it doesn't necessarily mean the old major version is deprecated.

The problem is that they look like warnings and will create more and more noise as a project gets older. Instead of putting it on a separate line, it could just be combined with the existing output.

$ go list -m -u all
example.com/my-module
github.com/BurntSushi/toml v0.3.1
github.com/mitchellh/go-wordwrap v1.0.0
github.com/peterbourgon/ff v1.6.0 [v1.7.0] [latest v3.1.0]

[peterbourgon]

The problem is that they look like warnings and will create more and more noise as a project gets older.

We propose only a single line of output per dependency, specifically with a "note" or "notice" (read: not "warning") prefix, output only the first time the dependency is added to a project, and identifying only the most recent version of that dependency. I don't think this looks like a warning, nor does it create more noise over time.

edit: Also, to me, putting the notification inline implies some level of compatibility between major versions that feels misleading.

Instead of putting it on a separate line, it could just be combined with the existing output.

By itself, this would be insufficiently obvious to solve the problem we're trying to solve with this proposal.