runInteractiveCommand/Process docs don't mention if handles are text or binary

runInteractiveCommand and runInteractiveProcess return newly created Handles. The haddock documentation for these actions does not specify if the Handles are opened in text or binary mode.

This caused at least one real-world bug where Cabal reads the output of ghc-pkg describe *, parsing it by splitting into lines. The standard haskell lines function splits on '\n' characters so we ended up with trailing '\r' characters. This was almost certainly because ghc-pkg was writing to stdout in text mode but Cabal was reading from the pipe in binary mode, presumably because currently runInteractiveCommand uses binary mode.

We probably don't want to have two versions of the functions so perhaps the documentation should specify what it does now and mention hSetBinaryMode for people who want to use that.

Trac metadata

Trac field	Value
Version	6.8.2
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	libraries/process
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system
Architecture