--build ignoring tsconfig.json changes

[asmundg]

TypeScript Version: 3.1.0-dev.20180817

Search Terms: --build tsconfig

Code

In learn-a, modifying package tsconfig.json files does not trigger rebuild when the package has already been built once.

yarn tsc --build packages/pkg1 --verbose
sed -i 's/"rootDir": "src"/"rootDir": "src","target":"es3"/' packages/pkg1/tsconfig.json
yarn tsc --build packages/pkg1 --verbose

Expected behavior:

pkg1 should rebuild after updating tsconfig.json

Actual behavior:

pkg1 is not rebuilt.

First execution of tsc:

message TS6355: Projects in this build: 
    * packages/pkg1/tsconfig.json

message TS6352: Project 'packages/pkg1/tsconfig.json' is out of date because output file 'packages/pkg1/lib/foo.js' does not exist

message TS6358: Building project '/home/asgramme/src/learn-a/packages/pkg1/tsconfig.json'...

Second execution of tsc, after modifying tsconfig.json:

message TS6355: Projects in this build: 
    * packages/pkg1/tsconfig.json

message TS6351: Project 'packages/pkg1/tsconfig.json' is up to date because newest input 'packages/pkg1/src/foo.ts' is older than oldest output 'packages/pkg1/lib/foo.js'

Done in 0.25s

Related Issues:

[AlCalzone]

I just ran into this aswell. Running tsc -b --clean before tsc -b sort of "fixes" it.