Output flag

[benjiqq]

What I did

add the flag "-o" to generate output files. this will write abi, bin and combined files. other options like ast, lll, opcodes need to be handled separately.

How I did it

add a flag to argparser and write the files

How to verify it

Description for the changelog

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 46.66667% with 8 lines in your changes missing coverage. Please review.

Project coverage is 84.67%. Comparing base (366e133) to head (cc4e024).
Report is 1076 commits behind head on master.

Files with missing lines	Patch %	Lines
vyper/cli/vyper_compile.py	46.66%	5 Missing and 3 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2452      +/-   ##
==========================================
+ Coverage   84.66%   84.67%   +0.01%     
==========================================
  Files          94       94              
  Lines        9446     9453       +7     
  Branches     2208     2209       +1     
==========================================
+ Hits         7997     8004       +7     
  Misses        939      939              
  Partials      510      510              

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[charles-cooper]

I think this PR will read a lot cleaner if you use a single branch, and just select a file handle depending on the option. If -o is set, set f to args.output_path. Otherwise, set it to sys.stdout.

[benjiqq]

I think this PR will read a lot cleaner if you use a single branch, and just select a file handle depending on the option. If -o is set, set f to args.output_path. Otherwise, set it to sys.stdout.

agreed, will do

[benjiqq]

@charles-cooper changed the PR as you suggested. if two arguments for the flags are passed doesn't work well.

vyper foo.vy -f bytecode,abi -o foo.txt writes 1 file without breakline

not really sure, in that case auto recognizing the format would be useful (write an abi and bin file separately).

[charles-cooper]

In order to avoid managing the resource manually (i.e. inserting calls to f.close() before every escape path), i think a bit of refactoring is in order. To abstract which file handle is being used, you could use a helper function

def cli_helper(f):
  ...

and then you would do something like

if args.output_path:
  with open(...) as f:
    cli_helper(f)
else:
  cli_helper(f)

[charles-cooper]

Also, please use print(..., file=f) instead of f.write(). The latter is a break with existing semantics -- it breaks existing flags (like -f ir)

[benjiqq]

@charles-cooper updated. I added end="" so that the output does not end with newline.

[charles-cooper]

@charles-cooper updated. I added end="" so that the output does not end with newline.

I think we can accept this PR but without the end="". That breaks the existing output format. I am open to the format change, but we should have an explicit discussion about it - either going through the VIP process or at least asking the major consumers of vyper if that's a breaking change for them first.

[charles-cooper]

Final nit: (style guide: functions private to a module should be prefixed with _)