preventive coding

[ktong]

more preventive coding to enhance integrity .

[codecov]

Codecov Report

Attention: 21 lines in your changes are missing coverage. Please review.

Comparison is base (ae80a16) 75.4% compared to head (6bfd23e) 73.8%.
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##            main     #77     +/-   ##
=======================================
- Coverage   75.4%   73.8%   -1.6%     
=======================================
  Files         17      17             
  Lines        618     662     +44     
=======================================
+ Hits         466     489     +23     
- Misses       141     155     +14     
- Partials      11      18      +7     

Files	Coverage Δ
provider/env/env.go	100.0% <100.0%> (ø)
provider/flag/flag.go	93.0% <100.0%> (+0.1%)	⬆️
provider/pflag/pflag.go	28.2% <100.0%> (+0.4%)	⬆️
default.go	83.3% <50.0%> (-7.6%)	⬇️
provider/file/file.go	93.1% <66.6%> (-6.9%)	⬇️
provider/fs/fs.go	87.5% <60.0%> (-12.5%)	⬇️
config.go	88.4% <75.9%> (-6.0%)	⬇️