Identify isolated extensions by exported name

[fmeum]

Instead of making a running counter and the dev_dependency bit the
identifier of an isolated module extension usage within a module file,
use the exported name of the usage. This still results in a stable name
even with --ignore_dev_dependency flips, but makes the canonical
repository name more recognizable and allows for less verbose buildozer
fixup commands.

[fmeum]

Stacked on #18829

[fmeum]

@Wyverald I rebased onto master.

[fmeum]

@bazel-io flag

[iancha1992]

@bazel-io fork 6.3.0

[iancha1992]

@fmeum @Wyverald looks like there's a conflict when attemting a cherry-pick to release-6.3.0. from the "src/main/java/com/google/devtools/build/lib/bazel/bzlmod/BazelDepGraphFunction.java"

"bestName" variable should not be:
String bestName = nonEmptyRepoPart + "~" + id.getExtensionName();

Instead, should be somewhat looks like below before the cherry-pick:

String bestName = id.getIsolationKey() .map( namespace -> String.format( "%s~_%s~%s~%s~%s", nonEmptyRepoPart, id.getExtensionName(), namespace.getModule().getName(), namespace.getModule().getVersion(), namespace.getUsageExportedName())) .orElse(nonEmptyRepoPart + "~" + id.getExtensionName());

Can you please take a look and let us know which commit to push in order to resolve this? Thanks!

cc: @bazelbuild/triage

[Wyverald]

It's safe to just use the longer snippet you pasted.

[keertk]

@fmeum @Wyverald we're not able to get this into rc1 (to go out shortly) unfortunately - there are still some failures in #18923.

Please let us know if this cherry-pick is required and we can create another release candidate in the coming days. Thanks!

Edit: pushed RC1 to 7/13, so we still have a day to get this in if needed.

[fmeum]

See #18923 (comment), a previous cherry-pick ended up partially reverting an earlier one.