Formatters return an empty string

[WillAbides]

Describe the bug Five of the revive's formatters always return an empty string for output. Instead of returning the output, they are writing directly to os.Stdout. The five formatters are default, friendly, ndjson, plain and unix.

To Reproduce Steps to reproduce the behavior:

Run this test: https://go.dev/play/p/b2yCM6m3PyM

expand

```go package main import ( "go/token" "os" "strings" "testing" "github.com/mgechev/revive/formatter" "github.com/mgechev/revive/lint" ) func TestFormatter(t *testing.T) { lintFailure := lint.Failure{ Failure: "test failure", RuleName: "rule", Category: "cat", Position: lint.FailurePosition{ Start: token.Position{ Filename: "test.go", Line: 2, Column: 5, }, End: token.Position{ Filename: "test.go", Line: 2, Column: 10, }, }, } for _, td := range []struct { name string formatter lint.Formatter want string }{ { name: "checkstyle", formatter: &formatter.Checkstyle{}, want: ` `, }, { name: "default", formatter: &formatter.Default{}, want: `test.go:2:5: test failure`, }, { name: "friendly", formatter: &formatter.Friendly{}, want: ` ⚠ https://revive.run/r#rule test failure test.go:2:5 ⚠ 1 problem (0 errors, 1 warning) Warnings: 1 rule `, }, { name: "json", formatter: &formatter.JSON{}, want: `[{"Severity":"warning","Failure":"test failure","RuleName":"rule","Category":"cat","Position":{"Start":{"Filename":"test.go","Offset":0,"Line":2,"Column":5},"End":{"Filename":"test.go","Offset":0,"Line":2,"Column":10}},"Confidence":0,"ReplacementLine":""}]`, }, { name: "ndjson", formatter: &formatter.NDJSON{}, want: `{"Severity":"warning","Failure":"test failure","RuleName":"rule","Category":"cat","Position":{"Start":{"Filename":"test.go","Offset":0,"Line":2,"Column":5},"End":{"Filename":"test.go","Offset":0,"Line":2,"Column":10}},"Confidence":0,"ReplacementLine":""}`, }, { name: "plain", formatter: &formatter.Plain{}, want: `test.go:2:5: test failure https://revive.run/r#rule`, }, { name: "sarif", formatter: &formatter.Sarif{}, want: ` { "runs": [ { "results": [ { "locations": [ { "physicalLocation": { "artifactLocation": { "uri": "test.go" }, "region": { "startColumn": 5, "startLine": 2 } } } ], "message": { "text": "test failure" }, "ruleId": "rule" } ], "tool": { "driver": { "informationUri": "https://revive.run", "name": "revive" } } } ], "version": "2.1.0" } `, }, { name: "stylish", formatter: &formatter.Stylish{}, want: ` test.go (2, 5) https://revive.run/r#rule test failure ✖ 1 problem (0 errors) (1 warnings) `, }, { name: "unix", formatter: &formatter.Unix{}, want: `test.go:2:5: [rule] test failure`, }, } { t.Run(td.name, func(t *testing.T) { dir := t.TempDir() realStdout := os.Stdout fakeStdout, err := os.Create(dir + "/fakeStdout") if err != nil { t.Fatal(err) } os.Stdout = fakeStdout defer func() { os.Stdout = realStdout }() failures := make(chan lint.Failure, 10) failures <- lintFailure close(failures) output, err := td.formatter.Format(failures, lint.Config{}) if err != nil { t.Fatal(err) } os.Stdout = realStdout err = fakeStdout.Close() if err != nil { t.Fatal(err) } stdout, err := os.ReadFile(fakeStdout.Name()) if err != nil { t.Fatal(err) } if len(stdout) > 0 { t.Errorf("formatter wrote to stdout: %q", stdout) } got := strings.TrimSpace(output) want := strings.TrimSpace(td.want) if got != want { t.Errorf("got %q, want %q", got, want) } }) } } ```

Expected behavior

I expect the test to pass because the output has been returned from the formatter and nothing was written to stdout.

Logs

--- FAIL: TestFormatter (0.01s)
    --- FAIL: TestFormatter/default (0.00s)
        testme_test.go:166: formatter wrote to stdout: "test.go:2:5: test failure\n"
        testme_test.go:171: got "", want "test.go:2:5: test failure"
    --- FAIL: TestFormatter/friendly (0.00s)
        testme_test.go:166: formatter wrote to stdout: "  ⚠  https://revive.run/r#rule  test failure  \n  test.go:2:5\n\n⚠ 1 problem (0 errors, 1 warning)\n\nWarnings:\n  1  rule  \n\n"
        testme_test.go:171: got "", want "⚠  https://revive.run/r#rule  test failure  \n  test.go:2:5\n\n⚠ 1 problem (0 errors, 1 warning)\n\nWarnings:\n  1  rule"
    --- FAIL: TestFormatter/ndjson (0.00s)
        testme_test.go:166: formatter wrote to stdout: "{\"Severity\":\"warning\",\"Failure\":\"test failure\",\"RuleName\":\"rule\",\"Category\":\"cat\",\"Position\":{\"Start\":{\"Filename\":\"test.go\",\"Offset\":0,\"Line\":2,\"Column\":5},\"End\":{\"Filename\":\"test.go\",\"Offset\":0,\"Line\":2,\"Column\":10}},\"Confidence\":0,\"ReplacementLine\":\"\"}\n"
        testme_test.go:171: got "", want "{\"Severity\":\"warning\",\"Failure\":\"test failure\",\"RuleName\":\"rule\",\"Category\":\"cat\",\"Position\":{\"Start\":{\"Filename\":\"test.go\",\"Offset\":0,\"Line\":2,\"Column\":5},\"End\":{\"Filename\":\"test.go\",\"Offset\":0,\"Line\":2,\"Column\":10}},\"Confidence\":0,\"ReplacementLine\":\"\"}"
    --- FAIL: TestFormatter/plain (0.00s)
        testme_test.go:166: formatter wrote to stdout: "test.go:2:5: test failure https://revive.run/r#rule\n"
        testme_test.go:171: got "", want "test.go:2:5: test failure https://revive.run/r#rule"
    --- FAIL: TestFormatter/unix (0.00s)
        testme_test.go:166: formatter wrote to stdout: "test.go:2:5: [rule] test failure\n"
        testme_test.go:171: got "", want "test.go:2:5: [rule] test failure"
FAIL
FAIL    github.com/mgechev/revive/testme    0.183s
FAIL

Desktop (please complete the following information):

• OS: MacOS 13.5.1
• Version of Go: 1.21.1

Additional context Add any other context about the problem here.