Remove tools/bazel.rc parsing

[dslomov]

Current documentation of how .bazerc files are parsed is here: https://docs.bazel.build/versions/master/user-manual.html#where-are-the-bazelrc-files

#6321 introduced a support for parsing tools/bazel.rc file to ease the transition.

How to migrate

(see the complete summary of changes in #6319 (comment))

%workspace%/tools/bazel.rc is replaced by %workspace%/.bazelrc. If you have the old file and want to support multiple versions of bazel - add the line import %workspace%/tools/bazel.rc at the top of your new .bazelrc file.

This file is in the same location as a file that used to be a "user-rc" (per-user configuration file for the project) - this is because it's the best place for it. If you have trouble transitioning though, because the user-rc was .gitignored, here is a suggestion for how to update your layout:

• Move the old .bazelrc to user.bazelrc
• Change the gitignore to ignoring that file.
• Add the line try-import %workspace%/user.bazelrc

[katre]

This is then also a release blocker for 0.19 (#6116).

[dslomov]

This bug is actually not a release blocker for 0.18, #6321 is.
However this bug is indeed a blocker for 0.19

[katre]

Once they are merged please comment on #6116 to let me know what the needed cherrypicks are. Thanks!

[cvcal]

The old list of bazelrcs was, in order:

• %workspace%/tools/bazel.rc (unless --nomaster_bazelrc)
• %binary_dir%/bazel.bazelrc (unless --nomaster_bazelrc)
• system rc, /etc/bazel.bazelrc or in %ProgramData% for Windows (unless --nomaster_bazelrc)
• the first of the following gets called the "user" bazelrc
  • path passed by flag --bazelrc
  • %workspace%/.bazelrc
  • $HOME/.bazelrc

The new list is hopefully a bit more consistent, as:

• system rc (unless --nosystem_rc) (same location as before)
• workspace, %workspace%/.bazelrc (unless --noworkspace_rc)
• user, $HOME/.bazelrc (unless --nohome_rc)
• command-line provided, passed as --bazelrc or nothing if the flag is absent.

This means that the following rc's will be ignored from now on:

• %workspace%/tools/bazel.rc
  1. This is replaced by %workspace%/.bazelrc. If you have the old file and want to support multiple versions of bazel - add the line import %workspace%/tools/bazel.rc at the top of your new .bazelrc file.
  2. Yes, this is in the same location as a file that used to be a "user-rc" - this is because it's the best place for it. If you have trouble transitioning though, because the user-rc was .gitignored, here is a suggestion for how to update your layout:
     1. Move the old .bazelrc to user.bazelrc
     2. Change the gitignore to ignoring that file.
     3. The workspace rc file, the new .bazelrc, can be checked in (and import tools/bazel.rc, if you need version compatibility as described above), and contain the line try-import %workspace%/user.bazelrc. This will allow users of this git project to optionally have the user rc, without erroring out for the users who do not need it.
• %binary_dir%/bazel.bazelrc
  • There is no replacement for the binary rc - there wasn't much of a use case for that and the system rc should be sufficient, but if you were using it, please import that file into your system rc.

[dslomov]

@katre Well actually this one is not a release blocker for 0.19 because that one is already cut. As long as you do not cherry-pick the fix for #6321 (don't), no action is needed.

However it is a release blocker for 0.20 (#6117)

[sgreenstein]

Where does the user rc reside on Windows?