# This file is a part of Julia. License is MIT: https://julialang.org/license
## initdefs.jl - initialization and runtime management definitions
"""
PROGRAM_FILE
A string containing the script name passed to Julia from the command line. Note that the
script name remains unchanged from within included files. Alternatively see
[`@__FILE__`](@ref).
"""
global PROGRAM_FILE::String = ""
"""
ARGS
An array of the command line arguments passed to Julia, as strings.
"""
const ARGS = String[]
"""
exit(code=0)
Stop the program with an exit code. The default exit code is zero, indicating that the
program completed successfully. In an interactive session, `exit()` can be called with
the keyboard shortcut `^D`.
"""
exit(n) = ccall(:jl_exit, Union{}, (Int32,), n)
exit() = exit(0)
const roottask = current_task()
is_interactive = false
"""
isinteractive() -> Bool
Determine whether Julia is running an interactive session.
"""
isinteractive() = (is_interactive::Bool)
## package depots (registries, packages, environments) ##
"""
DEPOT_PATH
A stack of "depot" locations where the package manager, as well as Julia's code
loading mechanisms, look for package registries, installed packages, named
environments, repo clones, cached compiled package images, and configuration
files. By default it includes:
1. `~/.julia` where `~` is the user home as appropriate on the system;
2. an architecture-specific shared system directory, e.g. `/usr/local/share/julia`;
3. an architecture-independent shared system directory, e.g. `/usr/share/julia`.
So `DEPOT_PATH` might be:
```julia
[joinpath(homedir(), ".julia"), "/usr/local/share/julia", "/usr/share/julia"]
```
The first entry is the "user depot" and should be writable by and owned by the
current user. The user depot is where: registries are cloned, new package versions
are installed, named environments are created and updated, package repos are cloned,
newly compiled package image files are saved, log files are written, development
packages are checked out by default, and global configuration data is saved. Later
entries in the depot path are treated as read-only and are appropriate for
registries, packages, etc. installed and managed by system administrators.
`DEPOT_PATH` is populated based on the [`JULIA_DEPOT_PATH`](@ref JULIA_DEPOT_PATH)
environment variable if set.
## DEPOT_PATH contents
Each entry in `DEPOT_PATH` is a path to a directory which contains subdirectories used by Julia for various purposes.
Here is an overview of some of the subdirectories that may exist in a depot:
* `artifacts`: Contains content that packages use for which Pkg manages the installation of.
* `clones`: Contains full clones of package repos. Maintained by `Pkg.jl` and used as a cache.
* `config`: Contains julia-level configuration such as a `startup.jl`.
* `compiled`: Contains precompiled `*.ji` files for packages. Maintained by Julia.
* `dev`: Default directory for `Pkg.develop`. Maintained by `Pkg.jl` and the user.
* `environments`: Default package environments. For instance the global environment for a specific julia version. Maintained by `Pkg.jl`.
* `logs`: Contains logs of `Pkg` and `REPL` operations. Maintained by `Pkg.jl` and Julia.
* `packages`: Contains packages, some of which were explicitly installed and some which are implicit dependencies. Maintained by `Pkg.jl`.
* `registries`: Contains package registries. By default only `General`. Maintained by `Pkg.jl`.
* `scratchspaces`: Contains content that a package itself installs via the [`Scratch.jl`](https://github.com/JuliaPackaging/Scratch.jl) package. `Pkg.gc()` will delete content that is known to be unused.
!!! note
Packages that want to store content should use the `scratchspaces` subdirectory via
[`Scratch.jl`](https://github.com/JuliaPackaging/Scratch.jl) instead of creating new
subdirectories in the depot root.
See also [`JULIA_DEPOT_PATH`](@ref JULIA_DEPOT_PATH), and
[Code Loading](@ref code-loading).
"""
const DEPOT_PATH = String[]
function append_bundled_depot_path!(DEPOT_PATH)
path = abspath(Sys.BINDIR, "..", "local", "share", "julia")
path in DEPOT_PATH || push!(DEPOT_PATH, path)
path = abspath(Sys.BINDIR, "..", "share", "julia")
path in DEPOT_PATH || push!(DEPOT_PATH, path)
return DEPOT_PATH
end
function init_depot_path()
empty!(DEPOT_PATH)
if haskey(ENV, "JULIA_DEPOT_PATH")
str = ENV["JULIA_DEPOT_PATH"]
# explicitly setting JULIA_DEPOT_PATH to the empty string means using no depot
isempty(str) && return
# otherwise, populate the depot path with the entries in JULIA_DEPOT_PATH,
# expanding empty strings to the bundled depot
populated = false
for path in eachsplit(str, Sys.iswindows() ? ';' : ':')
if isempty(path)
append_bundled_depot_path!(DEPOT_PATH)
else
path = expanduser(path)
path in DEPOT_PATH || push!(DEPOT_PATH, path)
populated = true
end
end
# backwards compatibility: if JULIA_DEPOT_PATH only contains empty entries
# (e.g., JULIA_DEPOT_PATH=':'), make sure to use the default depot
if !populated
pushfirst!(DEPOT_PATH, joinpath(homedir(), ".julia"))
end
else
push!(DEPOT_PATH, joinpath(homedir(), ".julia"))
append_bundled_depot_path!(DEPOT_PATH)
end
nothing
end
## LOAD_PATH & ACTIVE_PROJECT ##
# JULIA_LOAD_PATH: split on `:` (or `;` on Windows)
# first empty entry is replaced with DEFAULT_LOAD_PATH, the rest are skipped
# entries starting with `@` are named environments:
# - the first three `#`s in a named environment are replaced with version numbers
# - `@stdlib` is a special name for the standard library and expands to its path
# if you want a current env setup, use direnv and
# have your .envrc do something like this:
#
# export JULIA_LOAD_PATH="$(pwd):$JULIA_LOAD_PATH"
#
# this will inherit an existing JULIA_LOAD_PATH value or if there is none, leave
# a trailing empty entry in JULIA_LOAD_PATH which will be replaced with defaults.
const DEFAULT_LOAD_PATH = ["@", "@v#.#", "@stdlib"]
"""
LOAD_PATH
An array of paths for `using` and `import` statements to consider as project
environments or package directories when loading code. It is populated based on
the [`JULIA_LOAD_PATH`](@ref JULIA_LOAD_PATH) environment variable if set;
otherwise it defaults to `["@", "@v#.#", "@stdlib"]`. Entries starting with `@`
have special meanings:
- `@` refers to the "current active environment", the initial value of which is
initially determined by the [`JULIA_PROJECT`](@ref JULIA_PROJECT) environment
variable or the `--project` command-line option.
- `@stdlib` expands to the absolute path of the current Julia installation's
standard library directory.
- `@name` refers to a named environment, which are stored in depots (see
[`JULIA_DEPOT_PATH`](@ref JULIA_DEPOT_PATH)) under the `environments`
subdirectory. The user's named environments are stored in
`~/.julia/environments` so `@name` would refer to the environment in
`~/.julia/environments/name` if it exists and contains a `Project.toml` file.
If `name` contains `#` characters, then they are replaced with the major, minor
and patch components of the Julia version number. For example, if you are
running Julia 1.2 then `@v#.#` expands to `@v1.2` and will look for an
environment by that name, typically at `~/.julia/environments/v1.2`.
The fully expanded value of `LOAD_PATH` that is searched for projects and packages
can be seen by calling the `Base.load_path()` function.
See also
[`JULIA_LOAD_PATH`](@ref JULIA_LOAD_PATH),
[`JULIA_PROJECT`](@ref JULIA_PROJECT),
[`JULIA_DEPOT_PATH`](@ref JULIA_DEPOT_PATH), and
[Code Loading](@ref code-loading).
"""
const LOAD_PATH = copy(DEFAULT_LOAD_PATH)
# HOME_PROJECT is no longer used, here just to avoid breaking things
const HOME_PROJECT = Ref{Union{String,Nothing}}(nothing)
const ACTIVE_PROJECT = Ref{Union{String,Nothing}}(nothing) # Modify this only via `Base.set_active_project(proj)`
## Watchers for when the active project changes (e.g., Revise)
# Each should be a thunk, i.e., `f()`. To determine the current active project,
# the thunk can query `Base.active_project()`.
const active_project_callbacks = []
function current_project(dir::AbstractString)
# look for project file in current dir and parents
home = homedir()
while true
for proj in project_names
file = joinpath(dir, proj)
isfile_casesensitive(file) && return file
end
# bail at home directory
dir == home && break
old, dir = dir, dirname(dir)
dir == old && break
end
end
function current_project()
dir = try pwd()
catch err
err isa IOError || rethrow()
return nothing
end
return current_project(dir)
end
function parse_load_path(str::String)
envs = String[]
isempty(str) && return envs
for env in eachsplit(str, Sys.iswindows() ? ';' : ':')
if isempty(env)
for env′ in DEFAULT_LOAD_PATH
env′ in envs || push!(envs, env′)
end
else
if env == "@."
env = current_project()
env === nothing && continue
end
env = expanduser(env)
env in envs || push!(envs, env)
end
end
return envs
end
function init_load_path()
if haskey(ENV, "JULIA_LOAD_PATH")
paths = parse_load_path(ENV["JULIA_LOAD_PATH"])
else
paths = filter!(env -> env !== nothing,
String[env == "@." ? current_project() : env for env in DEFAULT_LOAD_PATH])
end
append!(empty!(LOAD_PATH), paths)
end
function init_active_project()
project = (JLOptions().project != C_NULL ?
unsafe_string(Base.JLOptions().project) :
get(ENV, "JULIA_PROJECT", nothing))
set_active_project(
project === nothing ? nothing :
project == "" ? nothing :
startswith(project, "@") ? load_path_expand(project) : abspath(expanduser(project))
)
end
## load path expansion: turn LOAD_PATH entries into concrete paths ##
function load_path_expand(env::AbstractString)::Union{String, Nothing}
# named environment?
if startswith(env, '@')
# `@.` in JULIA_LOAD_PATH is expanded early (at startup time)
# if you put a `@.` in LOAD_PATH manually, it's expanded late
env == "@" && return active_project(false)
env == "@." && return current_project()
env == "@stdlib" && return Sys.STDLIB
if startswith(env, "@scriptdir")
if @isdefined(PROGRAM_FILE)
dir = dirname(PROGRAM_FILE)
else
cmds = unsafe_load_commands(opts.commands)
if any((cmd, arg)->cmd_suppresses_program(cmd), cmds)
# Usage error. The user did not pass a script.
return nothing
end
dir = dirname(ARGS[1])
end
return abspath(replace(env, "@scriptdir" => dir))
end
env = replace(env, '#' => VERSION.major, count=1)
env = replace(env, '#' => VERSION.minor, count=1)
env = replace(env, '#' => VERSION.patch, count=1)
name = env[2:end]
# look for named env in each depot
for depot in DEPOT_PATH
path = joinpath(depot, "environments", name)
isdir(path) || continue
for proj in project_names
file = abspath(path, proj)
isfile_casesensitive(file) && return file
end
end
isempty(DEPOT_PATH) && return nothing
return abspath(DEPOT_PATH[1], "environments", name, project_names[end])
end
# otherwise, it's a path
path = abspath(env)
if isdir(path)
# directory with a project file?
for proj in project_names
file = joinpath(path, proj)
isfile_casesensitive(file) && return file
end
end
# package dir or path to project file
return path
end
load_path_expand(::Nothing) = nothing
"""
active_project()
Return the path of the active `Project.toml` file. See also [`Base.set_active_project`](@ref).
"""
function active_project(search_load_path::Bool=true)
for project in (ACTIVE_PROJECT[],)
project == "@" && continue
project = load_path_expand(project)
project === nothing && continue
# while this seems well-inferred, nevertheless without the type annotation below
# there are backedges here from abspath(::AbstractString, ::String)
project = project::String
if !isfile_casesensitive(project) && basename(project) ∉ project_names
project = abspath(project, "Project.toml")
end
return project
end
search_load_path || return
for project in LOAD_PATH
project == "@" && continue
project = load_path_expand(project)
project === nothing && continue
isfile_casesensitive(project) && return project
ispath(project) && continue
basename(project) in project_names && return project
end
end
"""
set_active_project(projfile::Union{AbstractString,Nothing})
Set the active `Project.toml` file to `projfile`. See also [`Base.active_project`](@ref).
!!! compat "Julia 1.8"
This function requires at least Julia 1.8.
"""
function set_active_project(projfile::Union{AbstractString,Nothing})
ACTIVE_PROJECT[] = projfile
for f in active_project_callbacks
try
Base.invokelatest(f)
catch
@error "active project callback $f failed" maxlog=1
end
end
end
"""
load_path()
Return the fully expanded value of [`LOAD_PATH`](@ref) that is searched for projects and
packages.
!!! note
`load_path` may return a reference to a cached value so it is not safe to modify the
returned vector.
"""
function load_path()
cache = LOADING_CACHE[]
cache !== nothing && return cache.load_path
paths = String[]
for env in LOAD_PATH
path = load_path_expand(env)
path !== nothing && path ∉ paths && push!(paths, path)
end
return paths
end
## atexit: register exit hooks ##
const atexit_hooks = Callable[]
const _atexit_hooks_lock = ReentrantLock()
global _atexit_hooks_finished::Bool = false
"""
atexit(f)
Register a zero- or one-argument function `f()` to be called at process exit.
`atexit()` hooks are called in last in first out (LIFO) order and run before
object finalizers.
If `f` has a method defined for one integer argument, it will be called as
`f(n::Int32)`, where `n` is the current exit code, otherwise it will be called
as `f()`.
!!! compat "Julia 1.9"
The one-argument form requires Julia 1.9
Exit hooks are allowed to call `exit(n)`, in which case Julia will exit with
exit code `n` (instead of the original exit code). If more than one exit hook
calls `exit(n)`, then Julia will exit with the exit code corresponding to the
last called exit hook that calls `exit(n)`. (Because exit hooks are called in
LIFO order, "last called" is equivalent to "first registered".)
Note: Once all exit hooks have been called, no more exit hooks can be registered,
and any call to `atexit(f)` after all hooks have completed will throw an exception.
This situation may occur if you are registering exit hooks from background Tasks that
may still be executing concurrently during shutdown.
"""
function atexit(f::Function)
Base.@lock _atexit_hooks_lock begin
_atexit_hooks_finished && error("cannot register new atexit hook; already exiting.")
pushfirst!(atexit_hooks, f)
return nothing
end
end
function _atexit(exitcode::Cint)
# Don't hold the lock around the iteration, just in case any other thread executing in
# parallel tries to register a new atexit hook while this is running. We don't want to
# block that thread from proceeding, and we can allow it to register its hook which we
# will immediately run here.
while true
local f
@lock _atexit_hooks_lock begin
# If this is the last iteration, atomically disable atexit hooks to prevent
# someone from registering a hook that will never be run.
# (We do this inside the loop, so that it is atomic: no one can have registered
# a hook that never gets run, and we run all the hooks we know about until
# the vector is empty.)
if isempty(atexit_hooks)
global _atexit_hooks_finished = true
break
end
f = popfirst!(atexit_hooks)
end
try
if hasmethod(f, (Cint,))
f(exitcode)
else
f()
end
catch ex
showerror(stderr, ex)
show_backtrace(stderr, catch_backtrace())
println(stderr)
end
end
end
## postoutput: register post output hooks ##
## like atexit but runs after any requested output.
## any hooks saved in the sysimage are cleared in Base._start
const postoutput_hooks = Callable[]
postoutput(f::Function) = (pushfirst!(postoutput_hooks, f); nothing)
function _postoutput()
while !isempty(postoutput_hooks)
f = popfirst!(postoutput_hooks)
try
f()
catch ex
showerror(stderr, ex)
show_backtrace(stderr, catch_backtrace())
println(stderr)
end
end
end
## hook for disabling threaded libraries ##
library_threading_enabled::Bool = true
const disable_library_threading_hooks = []
function at_disable_library_threading(f)
push!(disable_library_threading_hooks, f)
if !library_threading_enabled
disable_library_threading()
end
return
end
function disable_library_threading()
global library_threading_enabled = false
while !isempty(disable_library_threading_hooks)
f = pop!(disable_library_threading_hooks)
try
f()
catch err
@warn("a hook from a library to disable threading failed:",
exception = (err, catch_backtrace()))
end
end
return
end