nx affected not using cache as expected - am I misunderstanding?

[parky128]

We have Nx cloud setup for our organisation and I have successfully retrieved cached build results when trying out commands locally.

I am now experimenting with the nx affected command and am using it for building pull requests as part of our Jenkins pipeline script like so:

npx nx affected --base=origin/master --head=HEAD --target=build --parallel

I made a single file change to a lib and see its affected one of my projects as per the build output in first run

+ npx nx affected --base=origin/master --head=HEAD --target=build --parallel
>  NX  Running target build for 1 project(s):

  - console

———————————————————————————————————————————————
> nx run console:build:production 

Initial Chunk Files               | Names         |      Size
main.0f1f28a79fa3d077cc82.js      | main          |   1.71 MB
styles.6fbf9a51457db14d7ba9.css   | styles        | 611.91 kB
polyfills.692ca18ee72e90709635.js | polyfills     |  95.24 kB
runtime.4caf7ee059ec1e653ce1.js   | runtime       |   2.85 kB

| Initial Total |   2.40 MB

Lazy Chunk Files                  | Names         |      Size
660.8cc5e1691d3774afc603.js       | -             |   1.12 MB
259.8b2d8bd78d3a95d6bea8.js       | -             | 482.04 kB
415.1bf75b86d35b86dd75ca.js       | -             | 251.42 kB

Build at: 2021-09-22T12:09:04.892Z - Hash: a46e343a812938a4346c - Time: 110928ms

———————————————————————————————————————————————

>  NX   SUCCESS  Running target "build" succeeded



>  NX   CLOUD  See run details at XXXX

But when I re-run the same job without making any further changes, I see the same output above but with a new NX Cloud run results URL.

I would expect to see the previous build results retrieved from our Nx cloud cache.

I enabled logging and can see there's clearly a cache miss when I rebuild the PR job

+ npx nx affected --base=origin/master --head=HEAD --target=build --parallel
>  NX  Running target build for 1 project(s):

  - console

———————————————————————————————————————————————

>  NX   NOTE  Nx Cloud: Cache miss ff22a76441f5051d4f9ee1c637987b8b1285f11b863d16704dff84a4bb74c614.

and later after it completes the build task I see output showing

> NX NOTE Nx Cloud: Storing ff22a76441f5051d4f9ee1c637987b8b1285f11b863d16704dff84a4bb74c614

On each rebuild I try, with logging enabled I can see the computed hash changes, but no further changes are made to any files in between rebuilds, so I guess that answers why I am seeing cache misses.

Am I misunderstanding how this is meant to work?

[parky128]

OK figured out I was being dumb, but only because of the output from enabling Nx's extra logging.

So it turns out our projects package.json version property gets dynamically set via a setup step in our pipeline script which of course means it gets a different computed hash from the previous build.

Removing that step now gives me the behaviour I expected to see with Nx retrieving cached build results.

Lesson Learnt!