Make the single argument constructor inherit the env

[mjcarroll]

Now there are three ways to spawn a subprocess:

• Subprocess({"env"}) - Spawn subprocess and inherit environment from current executable
• Subprocess({"env"}, {}) - Spawn subprocess with empty custom environment
• Subprocess({"env"}, {"FOO=BAR"}) - Spawn subprocess with custom environment.

Opening for comment, still needs tests + docs

[codecov]

Codecov Report

Merging #113 (f59eccb) into gz-utils2 (8529918) will increase coverage by 1.21%.
The diff coverage is 100.00%.

❗ Current head f59eccb differs from pull request most recent head a81031c. Consider uploading reports for the commit a81031c to get more accurate results

@@              Coverage Diff              @@
##           gz-utils2     #113      +/-   ##
=============================================
+ Coverage      79.67%   80.89%   +1.21%     
=============================================
  Files              8        8              
  Lines            364      382      +18     
=============================================
+ Hits             290      309      +19     
+ Misses            74       73       -1     

Files	Coverage Δ
include/gz/utils/Subprocess.hh	97.14% <100.00%> (+0.53%)	⬆️
src/Environment.cc	88.52% <100.00%> (+1.48%)	⬆️

... and 1 file with indirect coverage changes

[azeey]

Windows CI is not happy

[mjcarroll]

Windows CI is not happy

And not in an expected place, I will take a look.

[mjcarroll]

@azeey should be good now

[azeey]

I like this signature, but would it does break API. Would it be possible to add Subprocess(const std::vector<std::string> &_commandLine, const std::vector<std::string> &_environment)` that would turn around and call this?

[mjcarroll]

Done, ended up refactoring out my strings -> map -> strings functions so I can use the delegating constructor here.

One hitch is that it makes the map and vector constructors ambiguous:

// Could be either
Subprocess({}, {})

So now you have to explicitly do:

Subprocess({}, gz::utils::EnvironmentMap{});

Not a huge deal, but a little less clean imo.

[azeey]

LGTM!