ICU version upgrade

Upgrade the ICU on Android to the new upstream version. The new upstream versions can be found at https://github.com/unicode-org/icu/releases.

The below contains the steps and commands in order to upgrade the ICU version in the AOSP.

Prerequisites

1. Install the prerequisite tools
   • See http://site.icu-project.org/repository
   • git-lts has to be installed to pull binaries correctly from the github.
   • git-filter-repo for rewriting the Change-Id later.
2. Generate a github read-access token and setup a local ~/.m2/setting.xml
   • See http://cldr.unicode.org/development/maven. This is required to download the prebuilt ICU to break the circular dependency between CLDR and icu.
3. Check out aosp/main
   • http://go/repo-init/aosp-main-with-phones

Branch Structure

1. external/icu project in the AOSP,
   • We rebase Android-specific patches on the icu-staging branch. Then we merge into aosp/main later.
2. external/cldr project
   • We use the `aosp/upstream-release-cldr as the mirror of the upstream release branch. We don’t modify this branch with Android patches, but merge this branch into aosp/main where the Android patches are located.

Verifying the cleanliness

1. Build the clean source of AOSP

   source build/envsetup.sh
   lunch aosp_cf_x86_64_phone-trunk_staging-userdebug
   m
   

   The build should succeed. Otherwise, your local repo may be broken. Please consider to re-sync.
2. Verify that the generated artifacts are clean
   • If you re-run the generation scripts and it causes new changes, some patches are missing in the sources, e.g. icu4j/ and icu4c or external/cldr.
   • The scripts include

   external/icu/tools/updatecldrdata.py
   external/icu/tools/updateicudata.py
   system/timezone/update-tzdata.py
   external/icu/tools/srcgen/generate_android_icu4j.sh
   external/icu/tools/icu4c_srcgen/generate_libandroidicu.py
   external/icu/tools/icu4c_srcgen/generate_ndk.py
   

Steps

1. Configure the versions and temp directory

   • Customize the following environment variables. The following example targets the ICU 76.1 and CLDR 46.0 version.

   export ICU_VERSION=76
   export ICU_MINOR_VERSION=1
   export CLDR_VERSION=46
   export ICU_UPGRADE_BUG=1234567890 # buganizer bug
   # Initially empty directory to store upstream source
   export UPSTREAM_CLDR_GIT=/media/user/disk/icu-git/cldr
   export UPSTREAM_ICU_GIT=/media/user/disk/icu-git/icu
   

2. Copy the CLDR sources into the upstream-release-cldr branch

   2a. Copy sources

   export CLDR_UPSTREAM_BRANCH=release-${CLDR_VERSION}
   
   cd ${ANDROID_BUILD_TOP}/external/cldr
   git fetch aosp upstream-release-cldr
   git branch ${CLDR_UPSTREAM_BRANCH} --track aosp/upstream-release-cldr
   git checkout ${CLDR_UPSTREAM_BRANCH}
   
   git clone https://github.com/unicode-org/cldr.git ${UPSTREAM_CLDR_GIT}
   
   git --git-dir=${UPSTREAM_CLDR_GIT}/.git --work-tree=${UPSTREAM_CLDR_GIT} fetch
   git --git-dir=${UPSTREAM_CLDR_GIT}/.git --work-tree=${UPSTREAM_CLDR_GIT} checkout ${CLDR_UPSTREAM_BRANCH}
   rm -rf *
   cp -r ${UPSTREAM_CLDR_GIT}/* .
   git clean -dfX # Remove ignored files
   git add -A
   git commit -F- <<EOF
   Copy upstream ${CLDR_UPSTREAM_BRANCH}
   
   Bug: ${ICU_UPGRADE_BUG}
   Test: n/a
   EOF
   # Upload this CL to upstream-release-cldr branch
   repo upload --cbr .
   

   2b. Merge the upstream sources with patches in aosp/main

   export CLDR_BRANCH=cldr${CLDR_VERSION}-main
   git branch ${CLDR_BRANCH} --track aosp/main
   git checkout ${CLDR_BRANCH}
   git merge ${CLDR_UPSTREAM_BRANCH} -m "
   Merge CLDR ${CLDR_VERSION} in upstream-release-cldr into aosp/main
   
   Bug: ${ICU_UPGRADE_BUG}
   Test: external/icu/tools/updatecldrdata.py
   "
   

   2c. Resolve any merge conflicts with the Android-specific patches. Continue creating the merge commit

   git merge --continue
   

   2d. Upload the CL to main branch

   repo upload --cbr .
   

3. Copy ICU upstream sources into external/icu

   cd ${ANDROID_BUILD_TOP}/external/icu
   export ICU_BRANCH=icu-staging
   export UPSTREAM_RELEASE_TAG=release-${ICU_VERSION}-${ICU_MINOR_VERSION}
   git fetch aosp main ${ICU_BRANCH}
   git branch ${ICU_BRANCH} --track aosp/${ICU_BRANCH}
   git checkout ${ICU_BRANCH}
   # Merge main into the staging branch.
   git merge --no-ff aosp/main -m
   "
   Merge branch aosp/main into ${ICU_BRANCH}
   
   Bug: ${ICU_UPGRADE_BUG}
   Test: n/a
   "
   # Clone the upstream CLDR repo locally to ${UPSTREAM_ICU_GIT}
   test -d ${UPSTREAM_ICU_GIT} || git clone https://github.com/unicode-org/icu.git ${UPSTREAM_ICU_GIT}
   
   git --git-dir=${UPSTREAM_ICU_GIT}/.git --work-tree=${UPSTREAM_ICU_GIT} fetch
   git --git-dir=${UPSTREAM_ICU_GIT}/.git --work-tree=${UPSTREAM_ICU_GIT} checkout ${UPSTREAM_RELEASE_TAG}
   find icu4j/ -type f,d ! -regex ".*/\(Android.mk\|Android.bp\|adjust_icudt_path.mk\|liblayout-jarjar-rules.txt\|.gitignore\|AndroidTest.xml\)" -delete
   find icu4c/ -type f,d ! -regex ".*/\(Android.mk\|Android.bp\|.gitignore\|AndroidTest.xml\)" -delete
   cp -r ${UPSTREAM_ICU_GIT}/icu4j .
   cp -r ${UPSTREAM_ICU_GIT}/icu4c .
   git checkout HEAD -- icu4c/.gitignore icu4j/.gitignore # Android has extra .gitignores. Use our version.
   rm -r tools/cldr
   cp -r ${UPSTREAM_ICU_GIT}/tools/cldr tools/cldr
   
   git add -A
   git commit -F- <<EOF
   Copy ICU ${UPSTREAM_RELEASE_TAG} into aosp/${ICU_BRANCH}
   
   Copy the files with the following commands:
   find icu4j/ -type f,d ! -regex ".*/\(Android.mk\|Android.bp\|adjust_icudt_path.mk\|liblayout-jarjar-rules.txt\|.gitignore\|AndroidTest.xml\)" -delete
   find icu4c/ -type f,d ! -regex ".*/\(Android.mk\|Android.bp\|.gitignore\|AndroidTest.xml\)" -delete
   cp -r \${UPSTREAM_ICU_GIT}/icu4j .
   cp -r \${UPSTREAM_ICU_GIT}/icu4c .
   git checkout HEAD -- icu4c/.gitignore icu4j/.gitignore
   rm -r tools/cldr
   cp -r \${UPSTREAM_ICU_GIT}/tools/cldr tools/cldr
   EOF
   

4. Apply Android-specific patches into external/icu

   4a. Cherry-pick the patches from the last staging branch. For example using the following query for ICU 71 patches

   • https://android-review.git.corp.google.com/q/%22Android+patch%22+branch:icu-staging+status:merged
   • The cherry-pick command is

     git cherry-pick <first_patch_in_the_chain>~1..<last_patch_in_the_chain>
     

   4b. Cherry-pick the patches since the ICU upgrade

   • Find the patches with this query. https://r.android.com/q/%2522Android+patch%2522+project:platform/external/icu+status:merged+-owner:automerger+-owner:android-build-coastguard-worker%2540google.com+branch:main 4c. Reset Change-Id in the cherry-picked CLs

   • THE_COPY_COMMIT=$(git log --pretty=format:'%h' -n 1 --grep "Copy ICU ${UPSTREAM_RELEASE_TAG} into aosp/${ICU_BRANCH}")
     git filter-branch -f --msg-filter 'sed "s/Change-Id: .*//g"' ${THE_COPY_COMMIT}..HEAD
     git rebase -i ${THE_COPY_COMMIT} # It should open vim
     # Replace pick with reword in vim `%s/pick /reword /g`
     # Close all commit message edits with :wq in vim
     # It triggers the git-hook to generate a Change-Id.
     # TODO: Find a better way to generate Change-Id
     

5. Regenerate and commit the artifacts

   5a. Update icu source data files

   croot external/icu
   tools/updatecldrdata.py
   
   git add -A
   git commit  -F- <<EOF
   Regenerated source data files with Android CLDR patches
   
   Source data files updated using:
   tools/updatecldrdata.py
   
   Test: n/a
   EOF
   

   5b. Update icu binary data files

   tools/updateicudata.py
   git add -A
   git commit -F- <<EOF
   Regenerated binary data files with Android CLDR patches
   
   Binary data files updated using:
   tools/updateicudata.py
   
   Test: n/a
   EOF
   

   5c. Pin the public API surface temporarily

   • We will later expose the new APIs after submitting the version upgrade CLs.

   ./tools/srcgen/generate_allowlisted_public_api.sh
   git add -A
   git commit -F- <<EOF
   Pin the current API list
   
   Test: ./tools/srcgen/generate_allowlisted_public_api.sh
   EOF
   

   5d. Regenerate android_icu4j/

   • Commands

   tools/srcgen/generate_android_icu4j.sh
   
   git add -A
   git commit -F- <<EOF
   Regenerate android_icu4j/ from icu4j/
   
   android_icu4j files updated using:
   tools/srcgen/generate_android_icu4j.sh
   
   Test: n/a
   EOF
   

   • If any java patches are not applied perfectly, remove the .orig and .rej files with the following command

   find android_icu4j/ -name *.orig -delete
   # Please manually update and resolve conflict of the java doc in android_icu4j/
   git commit -amend
   # Regenerate the patch files
   ./tools/srcgen/javadoc_patches/create_patches.sh
   git add -A && git commit -F- <<EOF
   Regenerate java doc patches
   
   Test: n/a
   EOF
   

   5e. Re-genereate libandroidicu/ sources

   ./tools/icu4c_srcgen/generate_libandroidicu.py
   git add -A && git commit  -F- <<EOF
   Regenerate libandroidicu
   
   The command:
   ./tools/icu4c_srcgen/generate_libandroidicu.py
   
   Test: n/a
   EOF
   

   5f. Regenerate libicu/ sources

   • Commands

   ./tools/icu4c_srcgen/generate_ndk.py
   
   git add -A && git commit -a  -F- <<EOF
   Regenerate libicu.so and ICU4C CTS headers
   
   The command:
   ./tools/icu4c_srcgen/generate_ndk.py
   
   Test: n/a
   EOF
   

   • Review the changes in libicu/ndk_headers/unicode. Check that no ABI change is in the C struct or API signature.

   git diff HEAD~1 ./libicu/ndk_headers/
   

   • May need to run this to update .patch files

   # Manually update doxygen doc in the .h headers in libicu/ndk_headers
   ./tools/icu4c_srcgen/doc_patches/create_patches.sh
   git add -A && git commit  -F- <<EOF
   Regenerate patches in libicu headers
   EOF
   

   5g. [Not required for every ICU release] Increment Distro major version

   • See https://android.googlesource.com/platform/system/timezone/+/main/README.android for details. Usually, it’s needed only when it’s the first ICU upgrade in the Android dessert release.

   5h. Generate time zone files

   cd $ANDROID_BUILD_TOP/system/timezone
   repo start ${ICU_BRANCH} .
   ./update-tzdata.py
   git add -A
   git commit -F- <<EOF
   Regenerate data files for ICU ${ICU_VERSION} upgrade
   
   Binary data files updated using:
   system/timezone/update-tzdata.py
   
   This updates the ICU version number inside of icu_tzdata.dat but doesn't
   change the timezone data itself.
   
   Bug: ${ICU_UPGRADE_BUG}
   Test: n/a
   EOF
   
   # If only the build time in icu4c/source/data/misc/zoneinfo64.txt, this step isn't needed. 
   cd $ANDROID_BUILD_TOP/external/icu
   git add -A
   git commit -F- <<EOF
   Regenerate tz-related data files
   
   Data files updated using:
   system/timezone/update-tzdata.py
   
   Bug: ${ICU_UPGRADE_BUG}
   Test: n/a
   EOF
   

   • Ideally, it should not generate new time zone data files if tzdata has been updated for a new tzdb release
   • If it updates time zone data, there could be extra changes from CLDR. Talk to android-libcore-team@ how to deal with the updates, because they may need to cherry-pick them into tzdata module updates.

   5i. Update the version numbers in the METADATA

   1. Update the external/icu/README.version
   2. Update version and upgrade date in external/cldr/METADATA
   3. git commit the file change

   5j. Regenerate frameworks/base/libs/androidfw/LocaleDataTables.cpp

   croot frameworks/base
   ./tools/localedata/extract_icu_data.py $ANDROID_BUILD_TOP > libs/androidfw/LocaleDataTables.cpp
   git commit -a -F- <<EOF
   Regenerate LocaleDataTables.cpp due to ICU ${ICU_VERSION} upgrade
   
   The command:
   ./tools/localedata/extract_icu_data.py \$ANDROID_BUILD_TOP > libs/androidfw/LocaleDataTables.cpp
   
   Bug: ${ICU_UPGRADE_BUG}
   Test: atest FrameworksCoreTests:android.text.format
   EOF
   

6. Build and run test

   6a. Build by m droid cts

   6b. Run the device tests by atest CtsIcu4cTestCases CtsIcuTestCases CtsLibcoreTestCases CtsLibcoreOjTestCases CtsBionicTestCases CtsTextTestCases minikin_tests -- --abi x86_64 # the primary ABI

   6c. [No longer needed] Run the host-side test by

   • ICU4J host-side test ant check
   • ICU4C host-side test make CINTLTST_OPTS=-w INTLTEST_OPTS=-w check (Currently, it has some failing tests. No of failures?)

   6d. If libcore/ tests are changed, verify the change

   • To verify the test change in ART MTS, run m mts && mts-tradefed run mts-art on Android S.
   • To verify the test change on LUCI bot, run art/tools/run-libcore-tests.sh --mode=host, because LUCI uses older ICU versions.

7. Upload the CLs to gerrit for code reviews from aosp/icu${ICU_VERSION} in external/icu and aosp/upstream-release-cldr in external/cldr

   repo upload --cbr -o nokeycheck -o uploadvalidator~skip --no-verify .
   

8. Merge aosp/icu* branch to aosp/main

   cd $ANDROID_BUILD_TOP/external/icu
   repo start icu${ICU_VERSION}-main .
   git merge --no-ff icu${ICU_VERSION} -m "
   Merge branch aosp/icu${ICU_VERSION} into aosp/main
   
   Bug: ${ICU_UPGRADE_BUG}
   Test: atest CtsIcu4cTestCases CtsIcuTestCases CtsLibcoreTestCases CtsLibcoreOjTestCases CtsBionicTestCases CtsTextTestCases minikin_tests
   "
   

9. Upload and submit changes from external/icu, external/cldr, libcore, frameworks/base, system/timezone

   10a. repo upload --cbr -o uploadvalidator~skip --no-verify .

   10b. Code review the diff in android_icu4j/src/main/tests/android/icu/extratest/expected_transliteration_id_list.txt * If a transliteration id is removed from the list, it may introduce app compatibility issues if the app depends on them. However, app has been warned to check the availability before invoking them. https://developer.android.com/reference/android/icu/text/Transliterator#getAvailableIDs()

10. After submitting all the CLs to aosp/main, expose the new stable ICU4J APIs to Android SDK

    rm tools/srcgen/allowlisted-public-api.txt
    ./tools/generate_android_icu4j.sh
    # Modify Icu4jTransform.java to allowlist more classes if needed. Check the error message for the details
    m update-api droid
    
    git commit -a -F- <<EOF
    Expose the new stable APIs from ICU4J ${ICU_VERSION}
    
    According to the upstream API coverage report external/icu/icu4j/coverage-exclusion.txt,
    the methods should have API coverage running in the existing CtsIcuTestCases.
    
    Bug: ${ICU_UPGRADE_BUG}
    Test: atest CtsIcuTestCases
    EOF
    

11. Send email android-libcore@ and icu-team@ to announce this.

    1. Some Android teams may have dependency on the new ICU version for other features.
    2. Email template

Hi, Libcore and ICU team,

ICU <version> just landed Android AOSP.
https://android.googlesource.com/platform/external/icu/+/main/README.version
as well as Android S (or Android 12).
https://googleplex-android.googlesource.com/platform/external/icu/+/sc-dev/README.version

Note:
- Contains bug fixes / build changes with a small set of API methods added.
- Unicode stays at version 14, and no new version has been published yet.

Historic version of this doc

http://g3doc/third_party/icu/g3doc/update/android