cmd/go: do not allow main module to replace itself

[GrigoriyMikhalkin]

Fixes #34417

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Message from Jay Conrod:

Patch Set 1:

(5 comments)

Thanks for working on this. A few changes needed though.

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This PR (HEAD: 0ad98f7) has been imported to Gerrit for code review.

Please visit https://go-review.googlesource.com/c/go/+/213118 to see it.

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Message from Greesha Mikhalkin:

Patch Set 2:

Patch Set 1:

(5 comments)

Thanks for working on this. A few changes needed though.

Thanks for clarifications. I updated PR

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Message from Bryan C. Mills:

Patch Set 2:

(1 comment)

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Message from Jay Conrod:

Patch Set 2:

(1 comment)

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This PR (HEAD: adc72ad) has been imported to Gerrit for code review.

Please visit https://go-review.googlesource.com/c/go/+/213118 to see it.

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Message from Segev Finer:

Patch Set 3:

I have seen projects replacing them self with themselves due to having a circular dependency, e.g:

replace github.com/gopher/mod => .

Does this block this so such projects can no longer work, or is there some other fix so this is no longer necessary.

(Yes, such circular dependencies are probably a bad idea, but some people just insist on doing them regardless)

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Message from Jay Conrod:

Patch Set 3:

I have seen projects replacing them self with themselves due to having a circular dependency, e.g:

replace github.com/gopher/mod => .

Does this block this so such projects can no longer work, or is there some other fix so this is no longer necessary.

(Yes, such circular dependencies are probably a bad idea, but some people just insist on doing them regardless)

Segev, this CL will report an error when the main module replaces itself or replaces another module with itself.

I don't think this kind replacement should be necessary, but please comment on golang.org/issue/34417 if you're running into a problem that's difficult to solve without this, and we'll try and recommend another solution.

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This PR is being closed because golang.org/cl/213118 has been abandoned.

Seems like we aren't going to do this, so abandoning. Please comment if you disagree.