Instead of storing timestamp of when last d.ts file was modified, store its name so buildinfo becomes portable again

[sheetalkamat]

As part of #31985, buildinfo was made portable but with latest change of store dts timestamp it looses that functionality.
With this change instead of storing timestamp of when the d.ts file was modified, we are storing name of that file so we can query its timestamp.
This also means, if d.ts files are same we wont rewrite them so the timestamp on disk can be trusted.

[andrewbranch]

How does this impact performance? Isn’t it more expensive to query those files?

[sheetalkamat]

We are querying only single file output file stamp only once and cache. (ABuildinfo stores the file name which should be latest so we dont have to query multiple files).. And during updates we update the timestamp to current time just like for buildInfo.. so watch updates should not incur this cost...

[sheetalkamat]

@andrewbranch i would like to get this in for 4.8

[amcasey]

@sheetalkamat In this context, "portable" means that you can share a tsbuildinfo across machines?

[sheetalkamat]

@amcasey Yes.

[amcasey]

@amcasey Yes.

I'm not sure I understand why another box would have the same "most recent" file. Is the assumption that it emitted the same files in the same order?

[andrewbranch]

Just a naming suggestion

[sheetalkamat]

I'm not sure I understand why another box would have the same "most recent" file. Is the assumption that it emitted the same files in the same order?

#32023 talks about caching tsbuildinfo and outDir across directories.. Given everything is copied, the file name of latestChangedDtsFile shoudnt change so checking its timestamp should be ok.

[amcasey]

I didn't look at the logic change, but the concept and the baseline changes make sense.