ceph is rebuilt although there is no change

[Lin Shuicheng]

Brief Description
-----------------
After sync latest code with new upgraded ceph. Although I have run build-pkgs successfully, if I run build-pkgs again, ceph will be rebuilt although there is no change. And ceph rebuild will cause about 1 hour.

Severity
--------
Minor.
This is just affect build time.

Steps to Reproduce
------------------
1. Sync clean latest code.
2. run "build-pkgs", ensure it could run successfully.
3. run "build-pkgs" again.

Expected Behavior
------------------
The 2nd "build-pkgs" should finish quickly, since only no srpm need be rebuilt.

Actual Behavior
----------------
ceph will be rebuilt in build-srpm stage, and lead to 1 hour build for build-rpm stage.
Here is the log
"
02:57:21 b2: ===== Build SRPM for 'ceph' =====
02:57:21 b2: PKG_BASE=/localdisk/designer/slin14/starlingx/cgcs-root/stx/stx-integ/ceph/ceph
02:57:21 b2: WORK_BASE=/localdisk/loadbuild/slin14/starlingx/std/inputs/stx/stx-integ/ceph/ceph
02:57:21 b2: RPMBUILD_BASE=/localdisk/loadbuild/slin14/starlingx/std/inputs/stx/stx-integ/ceph/ceph/rpmbuild
02:57:21 b2: Wrote: /localdisk/loadbuild/slin14/starlingx/std/rpmbuild/SOURCES/ceph/srpm_input.md5
02:57:21 b2: Rebuild required due to new or changed file: stx/git/ceph/src/.git_version
02:57:21 b2: MAKE_SRPM=centos/build_srpm
02:57:21 b2: DATA=centos/build_srpm.data
......
"

Reproducibility
---------------
100% with clean latest code.

System Configuration
--------------------
N/A

Branch/Pull Time/Commit
-----------------------
N/A

Last Pass
---------
N/A

Timestamp/Logs
--------------
N/A

Test Activity
-------------
Developer Testing

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/660867

[Ghada Khalil (gkhalil)]

Marking as low priority; build optimization; would be nice to fix, but does not gate any starlingx release.

[OpenStack Infra (hudson-openstack)]

Change abandoned by Lin Shuicheng (<email address hidden>) on branch: master
Review: https://review.opendev.org/660867
Reason: Abandon it since there is another patch to track this issue: https://review.opendev.org/661297

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/661297
Committed: https://git.openstack.org/cgit/starlingx/integ/commit/?id=663edb4567ad869227fcd0b02f259cb7e71300e3
Submitter: Zuul
Branch: master

commit 663edb4567ad869227fcd0b02f259cb7e71300e3
Author: Scott Little <email address hidden>
Date: Wed May 22 16:48:06 2019 -0400

    Ceph build script improvements to prevent needless rebuilds

    Problem: The file $SRC_DIR/src/.git_version is created by the
    custom build script and is not cleaned upon exit. The presence
    of the new file under $SRC_DIR will trigger a rebuild on the
    next iteration.

    Solution: Add a cleanup of the file to cover the normal exit case.
    This means $SRC_DIR/src/.git_version will not be present at the
    start of the next build.

    Problem: A lot of tarballs are copied into the build by the
    build script, rather than being listed in the COPY_LIST. This
    breaks the md5 checksum mechanism used to determine if a rebuild
    is required. A change to a tarball will be ignored and not
    trigger a rebuild.

    Solution: Move the code that generates the list of input tarballs
    into build_srpm.data. The file is sourced, so COPY_LIST can
    be populated dynamically.

    Problem: Script returns success when rpmbuild fails.

    Solution: Propogate the error code to the final exit.

    Change-Id: I2e760c24ecd3ce2d237863b948863c2a876d24fa
    Closes-Bug: 1830130
    Co-authored-by: Shuicheng Lin <email address hidden>
    Signed-off-by: Scott Little <email address hidden>

[Ghada Khalil (gkhalil)]

Adding the stx.2.0 release tag since the fix was merged for that release.