[Bug default/27616] New: libabigail treats empty and nearly empty XML elements inconsistently

[Bug default/27616] New: libabigail treats empty and nearly empty XML elements inconsistently

[gprocida+abigail at google dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=27616

            Bug ID: 27616
           Summary: libabigail treats empty and nearly empty XML elements
                    inconsistently
           Product: libabigail
           Version: unspecified
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: default
          Assignee: dodji at redhat dot com
          Reporter: gprocida+abigail at google dot com
                CC: libabigail at sourceware dot org
  Target Milestone: ---

At least in the case of abi-corpus, the case of "no children" is handled
differently from "only blank children". One consequence is that the
architecture of an empty corpus may be ignored if the XML is normalised or has
blank text stripped.

tests/data/test-abidiff/test-empty-corpus-2.xml:

<abi-corpus-group architecture='elf-arm-aarch64'>
  <abi-corpus path='vmlinux' architecture='elf-arm-aarch64'>
  </abi-corpus>
</abi-corpus-group>

Nothing changes if the inner element is changed to.

<abi-corpus path='vmlinux' architecture='elf-arm-aarch64'> </abi-corpus>

These are treated differently (abidiff reports architecture is ''):

<abi-corpus path='vmlinux' architecture='elf-arm-aarch64'></abi-corpus>

and

<abi-corpus path='vmlinux' architecture='elf-arm-aarch64'/>

I've not audited the code in detail, but any early return or similar
short-cutting on (!node->children) etc. should be reviewed.

Actually, the following shows plenty of places where whitespace is significant
where it should not be.

find tests -name '*.abi' -or -name '*.xml' | while read f; do
  <"$f" sed 's;^ *;;' | tr -d '\n' >"$f".wrung
  build/tools/abidiff --harmless "$f" "$f".wrung
done

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[Bug default/27616] libabigail treats empty and nearly empty XML elements inconsistently

[gprocida+abigail at google dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=27616

--- Comment #1 from Giuliano Procida <gprocida+abigail at google dot com> ---
Change posted for review here:
https://sourceware.org/pipermail/libabigail/2021q1/003324.html

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[Bug default/27616] libabigail treats empty and nearly empty XML elements inconsistently

[dodji at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=27616

dodji at redhat dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2021-04-14

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[Bug default/27616] libabigail treats empty and nearly empty XML elements inconsistently

[dodji at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=27616

--- Comment #2 from dodji at redhat dot com ---
I have posted an analysis of what is happening along with a response to your
patch at https://sourceware.org/pipermail/libabigail/2021q2/003382.html.

Thanks!

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[Bug default/27616] libabigail treats empty and nearly empty XML elements inconsistently

[gprocida at google dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=27616

gprocida at google dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |gprocida at google dot com

--- Comment #3 from gprocida at google dot com ---
I think this can be closed now.

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