Fix exception when parsing USFM with an empty verse paragraph

[ddaspit]

• fixes New Empty Stack USFM bombing issue serval#388

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This change is 

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 81.81818% with 6 lines in your changes are missing coverage. Please review.

Project coverage is 67.27%. Comparing base (61d792a) to head (7733533).

Files	Patch %	Lines
src/SIL.Machine/Corpora/ScriptureElement.cs	57.14%	2 Missing and 1 partial ⚠️
...chine/Corpora/ScriptureRefUsfmParserHandlerBase.cs	88.46%	0 Missing and 3 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #201      +/-   ##
==========================================
+ Coverage   67.24%   67.27%   +0.03%     
==========================================
  Files         441      441              
  Lines       34966    34993      +27     
  Branches     4689     4694       +5     
==========================================
+ Hits        23514    23543      +29     
+ Misses      10366    10361       -5     
- Partials     1086     1089       +3     

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[johnml1135]

@ddaspit - added more errors found from the sample project. You may have a specific way you want to fix them.

[johnml1135]

tests/SIL.Machine.Tests/Corpora/TestData/usfm/Tes/41MATTes.SFM line 5 at r2 (raw file):

\mt Matthew
\ip An introduction to Matthew\fe + \ft This is an endnote.\fe*
\p Here is another paragraph.

The current error is: System.InvalidOperationException : An error occurred while parsing the text 'MAT. Verse: MAT 1:0, offset: 179, error: 'Stack empty.'`. I still think that more context would be helpful - instead of people trying to count 179 tokens past the beginning of the verse (which starts exactly where?).

[ddaspit]

Thanks for adding the errors. I will look into them.

Reviewable status: 0 of 4 files reviewed, 1 unresolved discussion (waiting on @johnml1135)

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tests/SIL.Machine.Tests/Corpora/TestData/usfm/Tes/41MATTes.SFM line 5 at r2 (raw file):

Previously, johnml1135 (John Lambert) wrote…

The current error is: System.InvalidOperationException : An error occurred while parsing the text 'MAT. Verse: MAT 1:0, offset: 179, error: 'Stack empty.'`. I still think that more context would be helpful - instead of people trying to count 179 tokens past the beginning of the verse (which starts exactly where?).

We could do line number and column instead of verse ref and verse offset. It would be a bit more work, since the UsfmTokenizer and UsfmParser aren't tracking line number and column, but it should be doable.

[johnml1135]

tests/SIL.Machine.Tests/Corpora/TestData/usfm/Tes/41MATTes.SFM line 5 at r2 (raw file):

Previously, ddaspit (Damien Daspit) wrote…

We could do line number and column instead of verse ref and verse offset. It would be a bit more work, since the UsfmTokenizer and UsfmParser aren't tracking line number and column, but it should be doable.

Line number and offset (along with verse ref) would be nice - let's do it.

[johnml1135]

Reviewed 2 of 3 files at r1, 1 of 2 files at r2, 1 of 1 files at r3, 2 of 2 files at r4, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @ddaspit)

[johnml1135]

@ddaspit - Failed GetUsfm_NonVerse_Paragraph [84 ms]

[johnml1135]

Reviewed 3 of 3 files at r5, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @ddaspit)