Add support for SuggestedFixes

[ldez]

Is your feature request related to a problem? Please describe.

Add support for SuggestedFixes.

https://github.com/golang/tools/blob/b4639ccb830b1c9602f1c96eba624bbbe20650ea/go/analysis/doc/suggested_fixes.md

Describe the solution you'd like

Be able to apply automatically the fixes via --fix.

Describe alternatives you've considered

Display the suggestion as extra information.

Additional context

type Diagnostic struct {
	// ...

	// SuggestedFixes contains suggested fixes for a diagnostic which can be used to perform
	// edits to a file that address the diagnostic.
	// TODO(matloob): Should multiple SuggestedFixes be allowed for a diagnostic?
	// Diagnostics should not contain SuggestedFixes that overlap.
	// Experimental: This API is experimental and may change in the future.
	SuggestedFixes []SuggestedFix // optional


	// ...
}

https://github.com/golang/tools/blob/b4639ccb830b1c9602f1c96eba624bbbe20650ea/go/analysis/diagnostic.go#L23-L28

Current linters that support SuggestedFixes:

• goerr113
• ruleguard
• staticcheck
• nlreturn
• exportloopref
• exhaustive
• govet

Related to #1728

[ldez]

I'm working on and for now, I'm able to apply suggestions from goerr113 because the suggestions concern only one line.

For the other, the problem is a bit more complex because the fix must be applied on multiple lines.

[SVilgelm]

I think we need to print the suggested fixes if they are not applied (without --fix)

[ldez]

In some cases, it will be very weird to display the suggestions, because a suggestion can be a \n or the removal of a line, and TextEdits is a slice.

[SVilgelm]

agree

[SVilgelm]

we can print a diff, anyway you are going to create a diff, so we can print replacement, maybe in verbose output

[SVilgelm]

@ldez
I think we need to replace the Replacement with SuggestedFixes in golangci-lint, to avoid a transformation.

[ldez]

I think we can support both as the first step, but I'm thinking about it, I need more time.

[SVilgelm]

Here is the code of how to apply SuggestedFixes: https://github.com/golang/tools/blob/54dc8c5edb561003330ec7e649333181bbd0a9bd/go/analysis/internal/checker/checker.go#L316

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[nightlyone]

@ldez I guess this will be the next major feature after the generics issues are fixed? The developer productivity and happiness enabled by just clicking Apply Suggested fixes is quite significant on a Go ecosystem scale.

[ldez]

This issue is not related to GitHub review suggestions.
It's related to the CLI flag --fix of the command line.

[pohly]

Is there anything that can be done about this on a per-linter basis? In nunnatsa/ginkgolinter#63 (comment) it was pointed out that for some linters, fixing already works.

[ldez]

I plan to handle the topic by a breaking change, I don't want to introduce several ways to handle fixes.

[bombsimon]

Would you discourage and/or reject a PR for a linter specific implementation converting suggested fixes to replacements? I've added support for suggested fixers in a linter that only adds or removes a newline so converting it would be fairly simple. However maybe it's better to spend the time on a generic solution instead?

[ldez]

I think that it's the right thing for a linter to support SuggestedFixes (even if SuggestedFixes is still an experimental API), I also believe that we have to remove our custom implementation.

For now, it's better to not introduce partial or linter-specific support/converter, this is why the current PRs on the topic are still blocked.
But everything depends on the context and the scope of changes.

[Antonboom]

SuggestedFix is not experimental more.
https://github.com/golang/tools/blob/fa12f34b4218307705bf0365ab7df7c119b3653a/go/analysis/diagnostic.go#L54

[ldez]

the commit of the change: golang/tools@dbd6001

[Antonboom]

Related discussions:

1. Applying Suggested Fixes #2346
2. Can you help me understand "fieldalignment: struct with 40 pointer bytes could be 8" ? #2298 (reply in thread)

[StevenACoffman]

Additional linters that support SuggestedFixes:

• gocritic
• whitespace
• mirror
• misspell
• perfsprint
• testifylint
• usestdlibvars
• wsl

It's not clear to me if gci and gofumpt run as linters by golangci-lint would fully support the SuggestedFixes mechanism even if golangci-lint did, but those programs can correct their own identified issues.

FYI, until SuggestedFixes for all linters is supported in golangci-lint, you can individually install linters that support SuggestedFixes and run:

#!/bin/bash

# this will run all the lint fixes for all the module locally

function is_bin_in_path {
  builtin type -P "$1" &> /dev/null
}

function lintall {
    export GOBIN="$HOME/go/bin"
    ! is_bin_in_path gocritic && go install -v github.com/go-critic/go-critic/cmd/gocritic@latest
    ! is_bin_in_path whitespace && go install github.com/ultraware/whitespace/cmd/whitespace@latest
    ! is_bin_in_path wsl && go install github.com/bombsimon/wsl/v4/cmd/wsl@latest
    ! is_bin_in_path mirror && go install github.com/butuzov/mirror/cmd/mirror@latest
    ! is_bin_in_path misspell && go install github.com/client9/misspell/cmd/misspell@latest
    ! is_bin_in_path perfsprint && go install -v github.com/catenacyber/perfsprint@latest
    ! is_bin_in_path testifylint && go install github.com/Antonboom/testifylint@latest
    ! is_bin_in_path usestdlibvars && go install github.com/sashamelentyev/usestdlibvars@latest
    ! is_bin_in_path gci && go install github.com/daixiang0/gci@latest
    ! is_bin_in_path golines && go install github.com/segmentio/golines@latest
    ! is_bin_in_path gofumpt && go install mvdan.cc/gofumpt@latest
    ! is_bin_in_path golangci-lint && GOBIN=$HOME/go/bin curl -sSfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh | sh -s -- -b $GOBIN latest
    for D in */; do
        if [ -f "${D}go.mod" ]; then
            echo -e "\033[32m\xE2\x9c\x93 Running linting for ${D}\n\n\033[0m"
            cd "${D}"
            whitespace --fix ./... 2>&1 > /dev/null
            mirror --fix ./... 2>&1 > /dev/null
            perfsprint --fix ./... 2>&1 > /dev/null
            testifylint --suite-extra-assert-call.mode=require --fix ./... 2>&1 > /dev/null
            # usestdlibvars --fix ./... 2>&1 > /dev/null # noisy on generated files
            gci write -s standard -s default -s "prefix(github.com/Khan)" --skip-generated . 2>&1 > /dev/null
            gofumpt -w . 2>&1 > /dev/null
            wsl --fix . 
            "${HOME}/go/bin/golangci-lint" run --fix --config=~/Documents/git/districts-jobs/.golangci.yml ./...
            cd ..
        fi
    done
}

lintall

While some govet linters supports SuggestedFixes, go vet does not have a --fix flag to apply them. One of it's linters provides an independent entrypoint that does:

go install golang.org/x/tools/go/analysis/passes/fieldalignment/cmd/fieldalignment
fieldalignment -fix ./...

The other govet linters that support SuggestedFixes without an obvious corresponding installable entrypoint that can apply them:

• assign
• composite
• sigchanyzer
• sortslice
• stringintconv
• timeformat
• unreachable