If i want to test a change to rustdoc by re-rendering the std docs, i could combine the "rebuild rustdoc" and "render api docs" steps into an ./x.py doc command. If i wanted to avoid rebuilding all of stage1, then i could try ./x.py doc --stage 0, but that doesn't actually re-render the documentation! It gets to that step, sees that the documentation output is newer than the source files for libstd, then skips it. (The same problem occurs with ./x.py doc --stage 1 --keep-stage 0, on a related note.) This requires a rustdoc contributor to rebuild an entire stage to be able to test their change on a rendering of std. (Testing it by rendering a separate crate is still possible, i suppose, but also requires the additional step of linking the toolchain in rustup or using the test rustdoc/rustc by a different means.)
If i want to test a change to rustdoc by re-rendering the std docs, i could combine the "rebuild rustdoc" and "render api docs" steps into an
./x.py doccommand. If i wanted to avoid rebuilding all of stage1, then i could try./x.py doc --stage 0, but that doesn't actually re-render the documentation! It gets to that step, sees that the documentation output is newer than the source files for libstd, then skips it. (The same problem occurs with./x.py doc --stage 1 --keep-stage 0, on a related note.) This requires a rustdoc contributor to rebuild an entire stage to be able to test their change on a rendering of std. (Testing it by rendering a separate crate is still possible, i suppose, but also requires the additional step of linking the toolchain in rustup or using the test rustdoc/rustc by a different means.)