commit c301a28e97af8a1af140c4c60727ec3a50cf8611
author Filip Filmar <fmil@google.com> Wed Jul 08 15:29:34 2020 +0000
committer CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org> Wed Jul 08 15:29:34 2020 +0000
tree 5c712f03523ccfc2086c1f52a299b4f023fe6c07
parent 0b89dd4e3107bee63279e70ea417327091832da7

[icu] Automate ICU major version uprevs.

Added a configuration `//src/lib/icu:version` which automatically makes
available the major version number of the ICU library to non-ICU code
that needs to know it.

Then, wires the configuration through to `//third_party/rust_crates`.
This change required a recent change to `cargo_gnaw` to allow specifying
custom configs.  See fxr/404166 for that. (And, as fallout of that work,
fxr/404166 improves integration tests of `cargo_gnaw`.)

This bit of configuration makes atomic ICU version upgrades possible;
without it, simultaneous change of `//third_party/icu` and
`//third_party/rust_crates` would have been necessary.

With this configuration, an ICU uprev will automatically upgrade the
version in `//third_party/rust_crates`.

`//third_party/rust_crates` needs to know the major version number
because the version number is embedded into exported symbol names in the
ICU library.  C++ users get these renames via preprocessor magic, but
rust code needs to know the version explicitly.

For more details about renaming, look for "symbol renaming" at
http://userguide.icu-project.org/design

Also, ran `fx update-rustc-third-party`.

Fixed: 55481
Change-Id: Ib44063bda85efb6ddb380565767508c8917cfa77
Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/405214
Testability-Review: Filip Filmar <fmil@google.com>
Reviewed-by: Marc-Antoine Ruel <maruel@google.com>
Reviewed-by: Adam Perry <adamperry@google.com>
Commit-Queue: Filip Filmar <fmil@google.com>