Precompiled native code seems unused when a package is sourced from a git rev instead of a local path

General Usage
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On Julia 1.12.6, the same package at the same commit runs ~20x slower when it comes from Pkg.add(url=..., rev=...) than from a local path. The hot workload is a ModelingToolkit-generated, RuntimeGeneratedFunctions-wrapped ODE right-hand side that the package compiles in a PrecompileTools.@compile_workload; with the git-rev source it appears to be re-JIT’ed in every fresh process.

Repro (V3Kite.jl v1.0.1, ~3 min precompile per environment, two fresh processes):


using Pkg; Pkg.activate(tempname())

Pkg.add(url="https://github.com/OpenSourceAWE/V3Kite.jl", rev="v1.0.1")
Pkg.precompile()
using V3Kite; @time init(9.0, 200.0)      # 38.2 s

Fresh process; local clone of the same repo, checked out at v1.0.1

using Pkg; Pkg.activate(tempname())

Pkg.develop(path="/path/to/V3Kite.jl")
Pkg.precompile()
using V3Kite; @time init(9.0, 200.0)      # 1.8 s
V3Kite source plain julia --project with a PackageCompiler sysimage
url + rev 38.2 s 33.6 s
path 1.77 s 2.25 s

Under the git-rev source the workload does run: Pkg.precompile() logs it executing init, and leaves a ~141 MB pkgimage — same size class as the path build. So it compiles and is cached to disk, the native code is simply not used at runtime. Ruled out: the system image, the package’s own on-disk model cache, and the RuntimeGeneratedFunctions version (identical git-tree-sha1 in both manifests). Full measurement log incl. the dead ends: docs/sysimage_notes.md.

Is this expected — does a git-rev source invalidate RGF-backed precompiled code somehow — or is it a bug?

Disclaimer:
Written by Claude, manually proof-read and corrected

This is somewhat annoying, because it means I can make the original V3Kite package fast, but if I use that package as a dependency in another package it will be slow. Unless I dev it.