Explicitly build dynamic op libraries for wheel packaging

[czgdp1807]

Problem

When building the struct2tensor wheel, patchelf warnings occur during the stamp_wheel step,

patchelf: getting info about 'struct2tensor/ops/_decode_proto_map_op.so': No such file or directory

The stamp_wheel function expects all six dynamic op library files (.so) to be present in struct2tensor/ops/ before attempting to process them, but they were not being built and copied from Bazel's output directory.

Root Cause

With the upgrade to Protobuf 4.25.6, the build system changed:

• Before (Protobuf 3.21.9): The protobuf.bzl provided public macros (cc_proto_library, py_proto_library, proto_gen rule with gen_cc attribute) that automatically compiled .proto files to C++ .pb.cc/.pb.h files. These were used by dynamic library targets.
• After (Protobuf 4.25.6): These public macros were removed and replaced with internal underscored versions (_proto_gen, internal_py_proto_library). The old proto_gen rule also removed the gen_cc attribute, making C++ generation implicit and harder to trigger.

Bottom line: Protobuf 4.25.6 removed the public build rule APIs that struct2tensor's proto dependencies relied on. Without access to cc_proto_library from protobuf.bzl, the proto files in struct2tensor couldn't be compiled to C++, preventing the dynamic libraries from being built.

Solution

Add an explicit build_dynamic_libraries() function in build_common.sh that:

1. Builds each of the six dynamic op library targets using bazel build
2. Copies the built .so files from bazel-bin/struct2tensor/ops/ to struct2tensor/ops/
3. Runs before the bazel run :build_pip_package step to ensure files are staged for wheel creation

This ensures the .so files are present and valid before stamp_wheel attempts to patch them.

Files Changed

• build_common.sh: Added build_dynamic_libraries() function and integrated it into the build flow
• struct2tensor/tools/docker_build/build_manylinux.sh: Removed trailing whitespace

Testing

Wheel builds successfully with all dynamic libraries properly staged and patched.

[czgdp1807]

Here are the build logs,

.
.
.
+ for SO_FILE in "${libraries[@]}"
+ SO_FILE_PATH=struct2tensor/ops/_decode_proto_map_op.so
+ cp /tmp/tmp.qOjY11CtU8/struct2tensor/ops/_decode_proto_map_op.so /tmp/tmp.hWCK9OOEW6/struct2tensor/ops/_decode_proto_map_op.so
+ for SO_FILE in "${libraries[@]}"
+ SO_FILE_PATH=struct2tensor/ops/_decode_proto_sparse_op.so
+ cp /tmp/tmp.qOjY11CtU8/struct2tensor/ops/_decode_proto_sparse_op.so /tmp/tmp.hWCK9OOEW6/struct2tensor/ops/_decode_proto_sparse_op.so
+ for SO_FILE in "${libraries[@]}"
+ SO_FILE_PATH=struct2tensor/ops/_run_length_before_op.so
+ cp /tmp/tmp.qOjY11CtU8/struct2tensor/ops/_run_length_before_op.so /tmp/tmp.hWCK9OOEW6/struct2tensor/ops/_run_length_before_op.so
+ for SO_FILE in "${libraries[@]}"
+ SO_FILE_PATH=struct2tensor/ops/_equi_join_any_indices_op.so
+ cp /tmp/tmp.qOjY11CtU8/struct2tensor/ops/_equi_join_any_indices_op.so /tmp/tmp.hWCK9OOEW6/struct2tensor/ops/_equi_join_any_indices_op.so
+ for SO_FILE in "${libraries[@]}"
+ SO_FILE_PATH=struct2tensor/ops/_equi_join_indices_op.so
+ cp /tmp/tmp.qOjY11CtU8/struct2tensor/ops/_equi_join_indices_op.so /tmp/tmp.hWCK9OOEW6/struct2tensor/ops/_equi_join_indices_op.so
+ for SO_FILE in "${libraries[@]}"
+ SO_FILE_PATH=struct2tensor/ops/_parquet_dataset_op.so
+ cp /tmp/tmp.qOjY11CtU8/struct2tensor/ops/_parquet_dataset_op.so /tmp/tmp.hWCK9OOEW6/struct2tensor/ops/_parquet_dataset_op.so
+ rm /struct2tensor/dist/struct2tensor-0.49.0.dev0-cp311-cp311-manylinux_2_17_x86_64.manylinux2014_x86_64.whl
+ wheel version
wheel 0.46.3
+ wheel pack /tmp/tmp.hWCK9OOEW6 --dest-dir /struct2tensor/dist
Repacking wheel as /struct2tensor/dist/struct2tensor-0.49.0.dev0-cp311-cp311-manylinux2014_x86_64.manylinux_2_17_x86_64.whl...OK

[czgdp1807]

After merging this PR and #50 in my master branch locally, I tried both bazel build /... (inside docker container) and docker build --no-cache --build-arg TF_SERVING_VERSION_GIT_BRANCH=2.17.0 -t local/s2t_tf_serving .. Both are working fine. So @vkarampudi you can go ahead, merge both the PRs into master and start the release process.