testscript: phase out func() int in RunMain
#281
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We wanted the user's command functions to return an exit code as an int rather than calling os.Exit directly like a main function so that we could collect coverage profiles from subprocesses. This way, Go tests using testscript would still report the full code coverage information even when using nested processes. This all thankfully went away with Go 1.20, which introduced the same feature but built right into the toolchain for both `go test` and `go build`. As such, we were able to drop all of that code, including the bit that we ran before os.Exit. For more information, see: https://go.dev/blog/integration-test-coverage At this point, testscript users continue to use the `func() int` signature, via e.g. `func main1() int` out of inertia, but there's actually no good reason to keep doing that. It causes extra boilerplate and confuses new testscript users. Moreover, avoiding the use of os.Exit was rather tricky, for example see the former use of flag.ContinueOnExit in our tests. Add a new API, Main, which uses a `func()` signature just like `func main()`, meaning that no second function declaration is needed. Deprecate RunMain in favor of Main as well.
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This has been bugging me for some time so I did something about it. I'm not particularly set on the name |
rogpeppe
approved these changes
Nov 26, 2024
| @@ -58,18 +54,18 @@ func RunMain(m TestingM, commands map[string]func() int) (exitCode int) { | |||
| tmpdir, err := os.MkdirTemp("", "testscript-main") | |||
| if err != nil { | |||
| log.Printf("could not set up temporary directory: %v", err) | |||
| return 2 | |||
| os.Exit(2) | |||
| @@ -23,13 +23,11 @@ type TestingM interface { | |||
| // Deprecated: this option is no longer used. | |||
| func IgnoreMissedCoverage() {} | |||
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| // RunMain should be called within a TestMain function to allow | |||
| // Main should be called within a TestMain function to allow | |||
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This doc comment should point out that Main always invokes os.Exit and never returns.
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