Go 1.13: one shall not call flag.Parse() in init #56

New Issue

eclipseo · 2019-08-29T16:21:52Z

eclipseo commented

2019-08-29 16:21:52 +00:00

See bug https://github.com/golang/go/issues/33475 and bug https://github.com/golang/go/issues/31859 for the rationale

To be clear, we are talking only about flag.Parse here, not flag.*. The flag package is designed so that multiple packages can define flags, without those packages being aware of each other. It's essential that flag.Parse be called only after all flags are defined, meaning only after all packages are initialized. The normal practice is that the main package calls flag.Parse, because the main package is the only package that is sure to run after all packages are initialized.

Your program may well be designed so that it is OK to call flag.Parse in an init function of some non-main package. But most programs do not and cannot work that way. So I am questioning how much we should twist the testing package to support that use case. Of course if the change to the testing package is simple, then that is fine. But I would not like to see a lot of complexity added to support a very unusual use case.

This causes a bug when running tests in 1.13:

Testing    in: /builddir/build/BUILD/core/_build/src
         PATH: /builddir/build/BUILD/core/_build/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/sbin
       GOPATH: /builddir/build/BUILD/core/_build:/usr/share/gocode
  GO111MODULE: off
      command: go test -buildmode pie -compiler gc -ldflags "-X xorm.io/core/version=0.7.0 -extldflags '-Wl,-z,relro -Wl,--as-needed  -Wl,-z,now -specs=/usr/lib/rpm/redhat/redhat-hardened-ld '"
      testing: xorm.io/core
xorm.io/core
flag provided but not defined: -test.timeout
Usage of /tmp/go-build559150288/b001/core.test:
  -dbConn string
    	database connect string (default "root:@/core_test?charset=utf8")
  -dbtype string
    	database type (default "sqlite3")
exit status 2

See bug https://github.com/golang/go/issues/33475 and bug https://github.com/golang/go/issues/31859 for the rationale > To be clear, we are talking only about flag.Parse here, not flag.*. The flag package is designed so that multiple packages can define flags, without those packages being aware of each other. It's essential that flag.Parse be called only after all flags are defined, meaning only after all packages are initialized. The normal practice is that the main package calls flag.Parse, because the main package is the only package that is sure to run after all packages are initialized. > > Your program may well be designed so that it is OK to call flag.Parse in an init function of some non-main package. But most programs do not and cannot work that way. So I am questioning how much we should twist the testing package to support that use case. Of course if the change to the testing package is simple, then that is fine. But I would not like to see a lot of complexity added to support a very unusual use case. This causes a bug when running tests in 1.13: ``` Testing in: /builddir/build/BUILD/core/_build/src PATH: /builddir/build/BUILD/core/_build/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/sbin GOPATH: /builddir/build/BUILD/core/_build:/usr/share/gocode GO111MODULE: off command: go test -buildmode pie -compiler gc -ldflags "-X xorm.io/core/version=0.7.0 -extldflags '-Wl,-z,relro -Wl,--as-needed -Wl,-z,now -specs=/usr/lib/rpm/redhat/redhat-hardened-ld '" testing: xorm.io/core xorm.io/core flag provided but not defined: -test.timeout Usage of /tmp/go-build559150288/b001/core.test: -dbConn string database connect string (default "root:@/core_test?charset=utf8") -dbtype string database type (default "sqlite3") exit status 2 ```

lunny added the

bug

label 2019-08-30 02:04:30 +00:00

lunny commented

2019-08-30 05:23:10 +00:00

Closed by #57

lunny closed this issue

2019-08-30 05:23:10 +00:00

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