Avoid failing on source-file parsing errors

[timholy]

Fixes https://github.com/JuliaCI/Coverage.jl/issues/299. I'm not certain this is desirable, but...

[DilumAluthge]

I like the idea of printing a more informative message, explaining that there was a parsing error, and printing the name of the source file that had the parsing error.

I'm not sure I like the idea of completely suppressing the error. What if, after printing the informative message, you rethrow the error?

[timholy]

I'd wondered the same thing. I'd be happy to change it if that's your preference.

[DilumAluthge]

Hmmm. Let's see what Jameson and Max think.

[DilumAluthge]

Out of curiosity, is there a way for us to figure out what line the parsing error happened on? That would make it even easier for users to debug.

[coveralls]

Pull Request Test Coverage Report for Build 78

• 2 of 2 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.02%) to 97.268%

---

Totals
Change from base Build 75:	0.02%
Covered Lines:	178
Relevant Lines:	183

---

💛 - Coveralls

[coveralls]

Pull Request Test Coverage Report for Build 77

• 2 of 2 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.02%) to 97.268%

---

Totals
Change from base Build 75:	0.02%
Covered Lines:	178
Relevant Lines:	183

---

💛 - Coveralls

[DilumAluthge]

Suggested change

	end
	rethrow()
	end

[codecov-io]

Codecov Report

Merging #42 (829a4fa) into master (47f880e) will decrease coverage by 0.41%.
The diff coverage is 66.66%.

@@            Coverage Diff             @@
##           master      #42      +/-   ##
==========================================
- Coverage   96.41%   96.00%   -0.42%     
==========================================
  Files           4        4              
  Lines         223      225       +2     
==========================================
+ Hits          215      216       +1     
- Misses          8        9       +1     

Impacted Files	Coverage Δ
src/CoverageTools.jl	97.45% <66.66%> (-0.82%)	⬇️

---

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[timholy]

Out of curiosity, is there a way for us to figure out what line the parsing error happened on? That would make it even easier for users to debug.

#43

[fingolfin]

Both this and #43 would improve things, although PR #43 indeed seems more useful.

[DilumAluthge]

I prefer #43