RFC: only auto precompile the added package (+ deps) after an add operation

[KristofferC]

Many times in the global env I add some small package to try it out and then Pkg starts precompiling everything (even things I did not intend to load). This means I often have to interrupt it (which is a bit brittle) and it feels like it is doing something I didn't ask it to do.

With this, it will only compile the deps graph of the added packages. If a user want to load some other package later, the load precompile step will pick that up.

[IanButterworth]

The current approach aims at having the only thing that should cause load-time precompilation being changes to dev-ed packages. This moves more precompilation back to load time, when deps of other packages are changed by an add, which IMO would be a UX regression. But perhaps this is popular?

Personally I prefer the current arrangement and using the tiered_installed resolve strategy. Less changes, precompilation stays at install time.

[KristofferC]

The current approach aims at having the only thing that should cause load-time precompilation being changes to dev-ed packages.

Yeah, of course, if you precompile the world once you don't have to precompile it later.

which IMO would be a UX regression

Well, it is not a straight-up regression, it is a trade-off. It is a big win in the cases where you do add Foo; using Foo; Foo.do_what_I_want() in that it takes 10s, and not 10 minutes because you happen to have OrdinaryDiffEq also in the env (which I wasn't going to use).

---

To be honest, with load time precompilation I probably don't see much personal value in the add precompile. Maybe I'll just turn it off 🤷‍♂️ .

[IanButterworth]

I think we might have opposite opinions on this. Might be worth fielding opinions on slack?

[IanButterworth]

A fancy solution would be to be specific like this PR, but spawn off the rest of the Project work as a background thing afterwards.

The UI of that needs figuring out, but it might not be too tricky..

• notify that the rest of the project is being precompiled in the background. Use pkg> precompile --stop to interrupt
• always be silent, don't report success or errors

Pidfile locking should protect against races and we already report if the current process is holding the lock in an async task.

[KristofferC]

Right now, there is no way to turn off full precompilation of env on add while keeping precompilation of test env. :(

[KristofferC]

I must say this is sooo annoying.

(@v1.12) pkg> add Cthulhu
   Resolving package versions...
   Installed AbstractTrees ── v0.4.5
   Installed TypedSyntax ──── v1.3.1
   Installed WidthLimitedIO ─ v1.0.1
   Installed FoldingTrees ─── v1.2.1
   Installed JuliaSyntax ──── v0.4.9
   Installed Cthulhu ──────── v2.12.7
    Updating `~/.julia/environments/v1.12/Project.toml`
  [f68482b8] + Cthulhu v2.12.7
    Updating `~/.julia/environments/v1.12/Manifest.toml`
  [1520ce14] + AbstractTrees v0.4.5
  [f68482b8] + Cthulhu v2.12.7
  [1eca21be] + FoldingTrees v1.2.1
  [70703baa] + JuliaSyntax v0.4.9
  [d265eb64] + TypedSyntax v1.3.1
  [b8c1c048] + WidthLimitedIO v1.0.1
Precompiling all packages...
  Progress [==================================>      ]  237/287

Argh!! All the time.

And then I have to cancel it:

Precompiling all packages...
^CProgress [=====================================>   ]  263/287
[3454925] signal (2): Interrupt
in expression starting at /home/maleadt/manyjulias/bin/julia.jl:169
epoll_wait at /lib/x86_64-linux-gnu/libc.so.6 (unknown line)t
uv__io_poll at /workspace/srcdir/libuv/src/unix/epoll.c:236
uv_run at /workspace/srcdir/libuv/src/unix/core.c:400
ijl_task_get_next at /cache/build/default-amdci4-6/julialang/julia-release-1-dot-9/src/partr.c:390
 Interrupted: Exiting precompilation...

  4 dependencies had output during precompilation:
┌ SciMLBase
│  [3462422] signal 2: Interrupt
│  in expression starting at /home/kristofferc/.julia/packages/SciMLBase/hq1ku/src/callbacks.jl:158
│  trace_globals at /source/src/flisp/flisp.c:438
│  trace_globals at /source/src/flisp/flisp.c:440
│  trace_globals at /source/src/flisp/flisp.c:440
│  trace_globals at /source/src/flisp/flisp.c:440
│  trace_globals at /source/src/flisp/flisp.c:440
│  trace_globals at /source/src/flisp/flisp.c:440
│  trace_globals at /source/src/flisp/flisp.c:440
│  trace_globals at /source/src/flisp/flisp.c:440
│  trace_globals at /source/src/flisp/flisp.c:440
│  trace_globals at /source/src/flisp/flisp.c:440 [inlined]
│  gc at /source/src/flisp/flisp.c:582
│  apply_cl at /source/src/flisp/flisp.c:1360
│  _applyn at /source/src/flisp/flisp.c:679
│  fl_map1 at /source/src/flisp/flisp.c:2204 [inlined]
│  fl_map1 at /source/src/flisp/flisp.c:2192
│  apply_cl at /source/src/flisp/flisp.c:1224
│  _applyn at /source/src/flisp/flisp.c:679
│  fl_map1 at /source/src/flisp/flisp.c:2204 [inlined]
│  fl_map1 at /source/src/flisp/flisp.c:2192
│  apply_cl at /source/src/flisp/flisp.c:1224
│  _applyn at /source/src/flisp/flisp.c:679
│  fl_map1 at /source/src/flisp/flisp.c:2217 [inlined]
│  fl_map1 at /source/src/flisp/flisp.c:2192
│  apply_cl at /source/src/flisp/flisp.c:1224
│  _applyn at /source/src/flisp/flisp.c:679
└
┌ LoopVectorization
│  [3462400] signal 2: Interrupt
│  in expression starting at /home/kristofferc/.julia/packages/LoopVectorization/tIJUA/src/precompile.jl:4
│  _ZNK4llvm12MachineInstr12getSpillSizeEPKNS_15TargetInstrInfoE at /tmp/jl_BB7T81/bin/../lib/julia/libLLVM-17jl.so (unknown line)
└
┌ ClimaUtilities → ClimaUtilitiesClimaCoreInterpolationsExt
│  [3462490] signal 2: Interrupt
│  in expression starting at /home/kristofferc/.julia/packages/ClimaUtilities/zYtvC/ext/InterpolationsRegridderExt.jl:5
│  gc_mark_outrefs at /source/src/gc.c:2616 [inlined]
│  gc_mark_loop_serial_ at /source/src/gc.c:2891
│  gc_mark_loop_serial at /source/src/gc.c:2914
│  gc_mark_loop at /source/src/gc.c:3102 [inlined]
│  _jl_gc_collect at /source/src/gc.c:3474

and it is pages of errors.

[IanButterworth]

IMO it's an issue for people that work on master. We could turn it off for non tagged builds?

[KristofferC]

If add Foo precompiles everything why doesn't dev ./Foo precompile anything? Why would I want to be more likely to want to precompile IrrelevantPackage.jl if I do an add on some other package vs a dev?

[IanButterworth]

Why does everything else need re-precompiling? Because you're changing julia version a lot, no?

[IanButterworth]

Otherwise it's handled at install time for those packages.

[IanButterworth]

And IMO we should #3905 to help everyone avoid re-precompilation they don't really need

[IanButterworth]

Perhaps this could be merged behind a switch?

One reason I don't like it is that it dislocates cause and effect for precompilation activity. Like, add a package, updates a dep that is shared by another top level package. With this change the user will hit precompilation at a later stage and not know why, whereas currently they can see that a dep changed. For normal non package dev users, it reverts to the olden days of Pkg not really fully finishing the installation.