Incremental Builds are not Reliable v5.4.5 about typescript

[sheetalkamat]

This is working as intended.

tsc --b does not check dependencies for upto date ness. It only checks at your root files, output and referenced project upto date ness

Here is output

c:\temp\tsbuild-issue>pnpm build

> [email protected] build C:\temp\tsbuild-issue
> tsc -b -v .

[1:33:47 PM] Projects in this build:
    * tsconfig.core.json
    * tsconfig.json

[1:33:47 PM] Project 'tsconfig.core.json' is out of date because output file 'dist/compile.tsbuildInfo' does not exist

[1:33:47 PM] Building project 'C:/temp/tsbuild-issue/tsconfig.core.json'...


c:\temp\tsbuild-issue>pnpm add -D @types/[email protected]
Packages: +1 -1
+-
Progress: resolved 3, reused 2, downloaded 1, added 1, done

devDependencies:
- @types/vscode 1.88.0
+ @types/vscode 1.89.0

Done in 1.4s

c:\temp\tsbuild-issue>pnpm build

> [email protected] build C:\temp\tsbuild-issue
> tsc -b -v .

[1:34:07 PM] Projects in this build:
    * tsconfig.core.json
    * tsconfig.json

[1:34:07 PM] Project 'tsconfig.core.json' is up to date because newest input 'src/window.ts' is older than output 'dist/compile.tsbuildInfo'

[Jason3S]

Ahhh, that explains why it doesn't work as expected. It only takes local dependencies into account. That is too bad. It means I have to do tsc -b . -f. I take it that there isn't a compiler option to have it check external dependencies.

By the way, thank you for the -v option. I was certain it meant --version and it does, but the meaning magically changes with the -b option. Only after realizing that you used it in a way I hadn't seen did I think to try tsc -b . --help. Looking further, I see that there is a --help --all option that shows everything. But I was surprised that the meaning of an option changes dramatically based upon other options.

I will open a feature request to add a compile option to "monitor external dependencies". I would rather have it take a little bit long to compile reliably than to waste time trying to figure out why something wasn't working only to realize I needed to do a clean build.

To be clear, I was sure this was a bug. I had opened the .tsbuildinfo file to see if it was tracking the external dependencies. It is. It just is not using them for composite or incremental builds. I'm guessing it is there for watch. Which then leads to the question why watch behavior would be different than tsc -b .. Which explains #48314.