# Precompiling module each time without any change
**URL:** https://discourse.julialang.org/t/precompiling-module-each-time-without-any-change/99711
**Category:** General Usage
**Tags:** question
**Created:** [June 1, 2023, 7:55am UTC](https://discourse.julialang.org/t/precompiling-module-each-time-without-any-change/99711 "2023-06-01T07:55:20Z")
**Posts on this page:** 13
**Page:** 1
### Author:  [@peremato](https://discourse.julialang.org/u/peremato)
#### Post date: [June 1, 2023, 7:55am UTC](https://discourse.julialang.org/t/precompiling-module-each-time-without-any-change/99711/1 "2023-06-01T07:55:20Z")
Since I migrated to Julia 1.9 I get a pre-compilation of the module I am developing each time I start a test script. This was not the case with 1.8, for which I had sometimes to force a recompilation by modifying some of the files. Does anybody know how I can debug this to know what triggers the recompilation.
The module uses CxxWrap to interface to a C++ package. It is defined like this:
```julia
module Geant4
using CxxWrap
@wrapmodule("jlGeant4")
function __init__ ()
@initcxx
end
end #module
```
---
### Author:  [@tim.holy](https://discourse.julialang.org/u/tim.holy)
#### Post date: [June 1, 2023, 2:06pm UTC](https://discourse.julialang.org/t/precompiling-module-each-time-without-any-change/99711/2 "2023-06-01T14:06:07Z")
You do have to compile once for normal usage and once when running `Pkg.test` because it sets `coverage=true`, and we compile different code for those two cases. (Turning on coverage slows down runtime performance.) But if you’ve just run `Pkg.test`, and you re-run it without changing your source code, it shouldn’t need to `Precompiling...` any packages.
The only things I can thing of are
- are you sure it’s precompiling? `Pkg` will “reinstall” the test dependencies of your project, but if they’re already installed and precompiled from the previous `Pkg.test` run, that will basically be a no-op (lots of printing, but very little time, and specifically no `Precompiling...`).
- might there be anything wrong with the clock on your system?
- are you changing the DEPOT each time? That will result in fresh compilation
> for which I had sometimes to force a recompilation by modifying some of the files
Sounds like you might benefit from `include_dependency`, if some files are required for your project but don’t fit within the definition of ordinary Julia code.
---
### Author:  [@peremato](https://discourse.julialang.org/u/peremato)
#### Post date: [June 1, 2023, 2:36pm UTC](https://discourse.julialang.org/t/precompiling-module-each-time-without-any-change/99711/3 "2023-06-01T14:36:06Z")
> [@tim.holy](#):
>
> - are you sure it’s precompiling? `Pkg` will “reinstall” the test dependencies of your project, but if they’re already installed and precompiled from the previous `Pkg.test` run, that will basically be a no-op (lots of printing, but very little time, and specifically no `Precompiling...`).
> - might there be anything wrong with the clock on your system?
> - are you changing the DEPOT each time? That will result in fresh compilation
Yes, it is precompiling, at least is what is informing me.
```julia
Geant4.jl mato$ julia --project=. -i examples/basic/B2/B2a.jl
[Info: Precompiling Geant4 [559df036-b7a0-42fd-85df-7d5dd9d70f44]
```
If I execute again immediately after without any change, I get the same INFO message.
> [@tim.holy](#):
>
> Sounds like you might benefit from `include_dependency`, if some files are required for your project but don’t fit within the definition of ordinary Julia code.
Thanks for the hint, which is now not needed until I resolve the current problem.
---
### Author:  [@peremato](https://discourse.julialang.org/u/peremato)
#### Post date: [June 1, 2023, 2:50pm UTC](https://discourse.julialang.org/t/precompiling-module-each-time-without-any-change/99711/4 "2023-06-01T14:50:20Z")
BTW, this `Info` message only appears with the interactive option `-i`, but I’m sure it does the precompilation judging from the time it takes to start the script.
---
### Author:  [@ianshmean](https://discourse.julialang.org/u/ianshmean)
#### Post date: [June 1, 2023, 2:52pm UTC](https://discourse.julialang.org/t/precompiling-module-each-time-without-any-change/99711/5 "2023-06-01T14:52:45Z")
In non-interactive mode it’s a `@debug` so setting the env var `JULIA_DEBUG=Geant4` will make it show up
Edit: As @mkitti pointed out below this should be `JULIA_DEBUG=loading`
---
### Author:  [@mkitti](https://discourse.julialang.org/u/mkitti)
#### Post date: [June 1, 2023, 2:57pm UTC](https://discourse.julialang.org/t/precompiling-module-each-time-without-any-change/99711/6 "2023-06-01T14:57:56Z")
How is `Geant4` loaded? Have you modified the `LOAD_PATH` or set any environment variables? The results of `julia -e "using InteractiveUtils; versioninfo()"` would be informative here.
What is the output of `julia -E "DEPOT_PATH[1]"` ?
You might want to check `~/.julia/compiled/v1.9/Geant4` to see if there anything strange with the modified times of the files there.
---
### Author:  [@peremato](https://discourse.julialang.org/u/peremato)
#### Post date: [June 1, 2023, 2:58pm UTC](https://discourse.julialang.org/t/precompiling-module-each-time-without-any-change/99711/7 "2023-06-01T14:58:41Z")
No, it does not show up.
```julia
Geant4.jl mato$ JULIA_DEBUG=Geant4 julia --project=. examples/basic/B2/B2a.jl
**************************************************************
Geant4 version Name: geant4-11-01-patch-01 [MT] (10-February-2023)
<< in Multi-threaded mode >>
Copyright : Geant4 Collaboration
References : NIM A 506 (2003), 250-303
: IEEE-TNS 53 (2006), 270-278
: NIM A 835 (2016), 186-225
WWW : http://geant4.org/
**************************************************************...
```
---
### Author:  [@mkitti](https://discourse.julialang.org/u/mkitti)
#### Post date: [June 1, 2023, 3:00pm UTC](https://discourse.julialang.org/t/precompiling-module-each-time-without-any-change/99711/8 "2023-06-01T15:00:28Z")
Try `JULIA_DEBUG=loading`
---
### Author:  [@ianshmean](https://discourse.julialang.org/u/ianshmean)
#### Post date: [June 1, 2023, 3:03pm UTC](https://discourse.julialang.org/t/precompiling-module-each-time-without-any-change/99711/9 "2023-06-01T15:03:20Z")
Indeed, I got it wrong above. It will also tell you why any existing caches aren’t being used.
---
### Author:  [@peremato](https://discourse.julialang.org/u/peremato)
#### Post date: [June 1, 2023, 3:08pm UTC](https://discourse.julialang.org/t/precompiling-module-each-time-without-any-change/99711/10 "2023-06-01T15:08:05Z")
> [@mkitti](#):
>
> How is `Geant4` loaded?
I am developing Geant4.jl, so my current directory is the checkout area. This is why I set the project `--project=.`.
> [@mkitti](#):
>
> Have you modified the `LOAD_PATH` or set any environment variables?
No
> [@mkitti](#):
>
> `julia -e "using InteractiveUtils; versioninfo()"` would be informative here
```julia
Geant4.jl mato$ julia -e "using InteractiveUtils; versioninfo()"
Julia Version 1.9.0
Commit 8e630552924 (2023-05-07 11:25 UTC)
Platform Info:
OS: macOS (x86_64-apple-darwin22.4.0)
CPU: 8 × Intel(R) Core(TM) i7-7700HQ CPU @ 2.80GHz
WORD_SIZE: 64
LIBM: libopenlibm
LLVM: libLLVM-14.0.6 (ORCJIT, skylake)
Threads: 1 on 8 virtual cores
```
> [@mkitti](#):
>
> What is the output of `julia -E "DEPOT_PATH[1]"` ?
```julia
Geant4.jl mato$ julia -E "DEPOT_PATH[1]"
"/Users/mato/.julia"
```
> [@mkitti](#):
>
> You might want to check `~/.julia/compiled/v1.9/Geant4` to see if there anything strange with the modified times of the files there.
What I see strange is the date for the .dSYM files.
```julia
Geant4.jl mato$ ls -ls ~/.julia/compiled/v1.9/Geant4
total 152960
37624 -rwxrwxrwx 1 mato staff 19263064 May 31 18:55 GogkO_DkPlq.dylib
0 drwxr-xr-x 3 mato staff 96 May 10 18:13 GogkO_DkPlq.dylib.dSYM
136 -rw-r--r-- 1 mato staff 68134 May 31 18:55 GogkO_DkPlq.ji
37624 -rwxrwxrwx 1 mato staff 19263064 Jun 1 09:48 GogkO_d0CIK.dylib
0 drwxr-xr-x 3 mato staff 96 May 10 21:50 GogkO_d0CIK.dylib.dSYM
136 -rw-r--r-- 1 mato staff 68134 Jun 1 09:48 GogkO_d0CIK.ji
37624 -rwxrwxrwx 1 mato staff 19263064 Jun 1 16:57 GogkO_hxYin.dylib
0 drwxr-xr-x 3 mato staff 96 May 10 18:04 GogkO_hxYin.dylib.dSYM
136 -rw-r--r-- 1 mato staff 67987 Jun 1 16:57 GogkO_hxYin.ji
0 -rw------- 1 mato staff 0 May 19 08:53 jl_HPGSxk
136 -rw-r--r-- 1 mato staff 65953 May 16 10:52 jl_fTnfXe
0 -rw------- 1 mato staff 0 May 16 10:52 jl_vW7QTQ
39544 -rw-r--r-- 1 mato staff 20244600 May 16 10:52 jl_wJrpie
```
---
### Author:  [@peremato](https://discourse.julialang.org/u/peremato)
#### Post date: [June 1, 2023, 3:11pm UTC](https://discourse.julialang.org/t/precompiling-module-each-time-without-any-change/99711/11 "2023-06-01T15:11:54Z")
> [@mkitti](#):
>
> Try `JULIA_DEBUG=loading`
Great this helps!!
```julia
Geant4.jl mato$ JULIA_DEBUG=loading julia --project=. examples/basic/B2/B2a.jl
┌ Debug: Rejecting stale cache file /Users/mato/.julia/compiled/v1.9/Geant4/GogkO_hxYin.ji because file /Users/mato/Development/Julia/Geant4.jl/gen/build/lib/libGeant4Wrap does not exist
└ @ Base loading.jl:2798
┌ Debug: Rejecting stale cache file /Users/mato/.julia/compiled/v1.9/Geant4/GogkO_d0CIK.ji (mtime 1.684766294152994e9) because file /Users/mato/Development/Julia/Geant4.jl/src/Geant4.jl (mtime 1.6856198847355766e9) has changed
....
```
The file that exists is `/Users/mato/Development/Julia/Geant4.jl/gen/build/lib/libGeant4Wrap.dylib` with the suffix.
What I am doing in the module is:
```julia
module Geant4
using CxxWrap
using Geant4_jll
# Check whether the wrappers have been build locally otherwise use the binary package Geant4_julia_jll
gendir = normpath(joinpath(@ __DIR__ , "../gen"))
if isdir(joinpath(gendir, "build/lib"))
include(joinpath(gendir, "jl/Geant4-export.jl"))
@wrapmodule(joinpath(gendir, "build/lib", "libGeant4Wrap"))
else
using Geant4_julia_jll
include(Geant4_julia_jll.Geant4_exports)
@wrapmodule(Geant4_julia_jll.libGeant4Wrap)
end
....
```
I do to fully specify the suffix for portability. Probably I should specify it depending on the platform I am.
---
### Author:  [@peremato](https://discourse.julialang.org/u/peremato)
#### Post date: [June 1, 2023, 3:37pm UTC](https://discourse.julialang.org/t/precompiling-module-each-time-without-any-change/99711/12 "2023-06-01T15:37:56Z")
Problem solved. If I specify the full library name the precompilation is done only once on a change.
```julia
- @wrapmodule(joinpath(gendir, "build/lib", "libGeant4Wrap"))
+ @wrapmodule(joinpath(gendir, "build/lib", "libGeant4Wrap.$(Libdl.dlext)"))
```
However, I think this is a regression between 1.8 and 1.9. In [dlopen](https://gensoft.pasteur.fr/docs/julia/1.4.1/stdlib/Libdl.html#Libdl.dlopen) says that can be omitted.
---
### Author:  [@tim.holy](https://discourse.julialang.org/u/tim.holy)
#### Post date: [June 1, 2023, 3:54pm UTC](https://discourse.julialang.org/t/precompiling-module-each-time-without-any-change/99711/13 "2023-06-01T15:54:42Z")
If you could come up with a MWE that would be fantastic for fixing the regression. (We need a test to see if the problem has been fixed and stays that way.) Either way, it should be reported.