do not override already set content-type, fixes #1120

[fl0w]

semver major, #1114

This could be done as semver minor - if an application setting is addd, e.g. app.responsOverride = true or something.

[codecov]

Codecov Report

Merging #1131 into master will not change coverage.
The diff coverage is 100%.

@@           Coverage Diff           @@
##           master    #1131   +/-   ##
=======================================
  Coverage   99.73%   99.73%           
=======================================
  Files           5        5           
  Lines         372      372           
=======================================
  Hits          371      371           
  Misses          1        1

Impacted Files	Coverage Δ
lib/response.js	100% <100%> (ø)	⬆️

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[jonathanong]

this might break apps if someone is relying on this behavior, so i would wait for semver major.

[jonathanong]

unless we only set it to json if the type is not json-like

[fl0w]

Yes, definitely semver-major.
Though with this PR, #1137, #1115 and a few more a v3 is already justified (IMO).

It would be nice to drop a v3 alpha, call out EOL for v1 (soon-ish?) and break the stigma of having to rewrite Koa to justify a major bump and add proper deprecations to v2 and v1.

[niftylettuce]

I agree @fl0w

[jkomyno]

Any news about this PR? @jonathanong

[jkomyno]

Hi, it's been two years, any update on this PR?
@jonathanong @3imed-jaberi @dead-horse @dougwilson