https://travis-ci.org/pantsbuild/pex/builds/270271351 was the last CI

if you could guide me I can fix the tests as well

How is the build dictionary auto generated? I am trying to see if given a

target

in pants, if there is a way to grab all its fields identical to what’s specified in the build dictionary, then serialize it back to how it is defined originally

hey all. I'm a new pants user at foursquare and I've been running experiments on incremental builds in pants vs sbt. It seems like pants does downstream invalidation when an upstream dep has a private change, and sbt doesn't. @limited-country-20626 recommended I ping this group to see if it's worth doing some more research. dets here https://github.com/abe-winter-4s/incremental-builds

Pants uses SBT’s incremental compiler under the hood, so you should get the same behavior in both cases

It’s possible that Pants is on an older version of SBT with less fine-grained invalidation behavior

Also, when you say that “Pants invalidates B” - since B depends on A, if A changes Pants must invalidate B at the target level. Pants itself doesn’t understand semantic invalidation (although that would be an awesome project). But all that means is that it runs SBT’s incremental compiler on B, which no-ops, since SBT knows that nothing actually needs to be recompiled.

So if by “Pants invalidates B” you mean “Pants runs Zinc on B” then, yes, that is expected. But if Zinc does anything except return immediately, then that’s not expected.

that's consistent with what I'm seeing

Basically, Pants delegates to SBT, which makes the same decision in both cases.

But this should be a fast Nailgun call

but the changed upstream target will have a new path, right? (because the path includes the fingerprint)

is it possible zinc is confused by the changed path and rebuilding the downstream target?

or rather, the

.class

files / zinc intermediates will be in a new place. (and I may not know what I'm talking about here)

welcome Abe!

@crooked-telephone-38431: it should be using the stable path (the

current

symlink), but i haven't looked recently

can pop open an analysis file to see.

talked IRL w/ mateo and did some more digging. I'm looking at a zinc command:

-analysis-cache /Users/awinter/foursquare.web/.pants.d/compile/zinc/252d64521cf9/src.jvm.com.foursquare.apiserver.api2.oauth2.oauth2/current/src.jvm.com.foursquare.apiserver.api2.oauth2.oauth2.analysis

(this is from older pants)

looks like there's a checksum in there

unless that's the checksum for the zinc tool, not for the target

open up the analysis file itself

it's (currently) text

inside the

.analysis

file, I'm seeing lines like this:

/Users/awinter/foursquare.web/src/jvm/com/foursquare/apiserver/api2/oauth2/AuthenticateFlow.scala -> /Users/awinter/foursquare.web/.pants.d/compile/zinc/252d64521cf9/src.jvm.com.foursquare.apiserver.api2.oauth2.oauth2/current/classes/com/foursquare/apiserver/api2/oauth2/AuthenticateFlow$$anonfun$handle$1.class

or simpler approach: this log seems to be saying that pants invoked zinc on target B but zinc didn't rebuild anything.

[1/2] Compiling 1 zinc source in 1 target (src/main/scala/A:A).
13:58:11 00:02       [compile]

13:58:11 00:02         [zinc]
                       [info] Compiling 1 Scala source to /Users/awinter/tuts/increment/.pants.d/compile/zinc/c95338cea9cc/src.main.scala.A.A/current/classes...
                       [info] Compile success at Sep 13, 2017 1:58:11 PM [0.559s]

                   [2/2] Compiling 1 zinc source in 1 target (src/main/scala/B:B).
13:58:11 00:02       [compile]

13:58:11 00:02         [zinc]
                       [info] Compile success at Sep 13, 2017 1:58:11 PM [0.015s]

that sounds right, yes

with regard to classfiles changing location: i believe that it will use the analysis of the dependency module to decide that the api hasn't changed

you can turn on a bunch more invalidation logging by changing the log level to debug

and then by passing additional flags to zinc

(but note that pantsbuild master is on a significantly newer version of zinc due to https://github.com/pantsbuild/pants/pull/4729 not having landed yet)