Gerrit trivial rebase detection ignores whitespace

[Jeremy Stanley]

The recently-implemented trivial rebase detection hook on review.openstack.org's Gerrit instance ( https://bugs.launchpad.net/openstack-ci/+bug/881184 ) is working as designed upstream but works on a premise which is less helpful for whitespace-significant languages. In particular, it relies on git patch-id which squashes all whitespace characters between patches prior to comparing them.

Several possible approaches are being explored to modify this behavior, but the current line of thinking is that code reviews for OpenStack should only be automatically reapplied if there are no whitespace changes in a rebase (offset/linecount changes only). The script should still comment on a new patchset indicating that it notices only whitespace changes, similar to how it identifies patchsets containing only commit message changes.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/13775

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/13775
Committed: http://github.com/openstack/openstack-ci-puppet/commit/2be93cc22e35a07c1c082308ac52d8b8635dc9ef
Submitter: Jenkins
Branch: master

commit 2be93cc22e35a07c1c082308ac52d8b8635dc9ef
Author: Jeremy Stanley <email address hidden>
Date: Thu Sep 27 18:15:49 2012 +0000

    Gerrit Whitespace Change Detection

    Consider whitespace changes significant enough not to reapply code
    reviews, but still comment if that's all which changed between
    patchsets. This addresses bug 1057506.

    * modules/openstack_project/files/gerrit/scripts/trivial_rebase.py
    (GetPatchId): Add a flag called consider_whitespace, but defaulting to
    False so as to preserve default behavior of the module. Add conditional
    behavior to replace all spaces and tabs with percent signs before
    calculating the patch-id hash.
    (Main): Add a --whitespace command-line option to turn on whitespace
    change checking. If enabled and if normal GetPatchId calls return a
    match, re-run with consider_whitespace set to True and apply a comment
    to the new patchset in Gerrit if the result is non-matching.

    * modules/openstack_project/templates/gerrit_patchset-created.erb: Add
    --whitespace to the trivial_rebase.py invocation, enabling whitespace
    checking.

    Change-Id: I89c479614a637717cf515a5d3f6d03b5f7830581