RFC: implement proper debug mode for packages (with support for re-precompilation)

NEWS.md

@@ -84,6 +84,11 @@ New library functions
  efficiently ([#35816]).
 * New function `addenv` for adding environment mappings into a `Cmd` object, returning the new `Cmd` object.
 * New function `insorted` for determining whether an element is in a sorted collection or not ([#37490]).
+* New function `isdebug` for checking if julia is running in debug mode.
+ Packages use different precompile caches in debug and non-debug mode thus it
+ safe to use this function for compile time decisions. Also, note that
+ `@assert` now is a no-op unless `isdebug()` is true. Debug mode is activated
+ with the `-g2` flag.
 
 New library features
 --------------------
@@ -124,6 +129,8 @@ Standard library changes
 * The `Pkg.Artifacts` module has been imported as a separate standard library. It is still available as
  `Pkg.Artifacts`, however starting from Julia v1.6+, packages may import simply `Artifacts` without importing
  all of `Pkg` alongside. ([#37320])
+* The `@assert` macro is now only active when julia is started with a debug
+ level of 2 (`julia -g2`).
 
 #### LinearAlgebra
 

base/Base.jl

@@ -66,6 +66,9 @@ time_ns() = ccall(:jl_hrtime, UInt64, ())
 
 start_base_include = time_ns()
 
+julia_debug = true
+isdebug() = julia_debug::Bool
+
 ## Load essential files and libraries
 include("essentials.jl")
 include("ctypes.jl")
@@ -396,6 +399,7 @@ in_sysimage(pkgid::PkgId) = pkgid in _sysimage_modules
 
 if is_primary_base_module
 function __init__()
+ global julia_debug = Base.JLOptions().debug_level >= 2
  # try to ensuremake sure OpenBLAS does not set CPU affinity (#1070, #9639)
  if !haskey(ENV, "OPENBLAS_MAIN_FREE") && !haskey(ENV, "GOTOBLAS_MAIN_FREE")
  ENV["OPENBLAS_MAIN_FREE"] = "1"

base/error.jl

@@ -183,21 +183,25 @@ windowserror(p, b::Bool; extrainfo=nothing) = b ? windowserror(p, extrainfo=extr
 windowserror(p, code::UInt32=Libc.GetLastError(); extrainfo=nothing) = throw(Main.Base.SystemError(string(p), 0, WindowsErrorInfo(code, extrainfo)))
 
 
-## assertion macro ##
+## assertion and ifdebug macros ##
+
+"""
+ @ifdebug expr
+
+Equivalent to `@static if isdebug()`
+"""
+macro ifdebug(expr)
+ isdefined(@__MODULE__, :isdebug) && !(isdebug()) && return nothing
+ return :(esc(expr))
+end
 
 
 """
  @assert cond [text]
 
 Throw an [`AssertionError`](@ref) if `cond` is `false`. Preferred syntax for writing assertions.
-Message `text` is optionally displayed upon assertion failure.
-
-!!! warning
- An assert might be disabled at various optimization levels.
- Assert should therefore only be used as a debugging tool
- and not used for authentication verification (e.g., verifying passwords),
- nor should side effects needed for the function to work correctly
- be used inside of asserts.
+Message `text` is optionally displayed upon assertion failure. Only active when julia is started
+in debug mode (`julia -g`).
 
 # Examples
 ```jldoctest
@@ -208,6 +212,7 @@ julia> @assert isodd(3) "What even are numbers?"
 ```
 """
 macro assert(ex, msgs...)
+ isdefined(@__MODULE__, :isdebug) && !(isdebug()) && return nothing
  msg = isempty(msgs) ? ex : msgs[1]
  if isa(msg, AbstractString)
  msg = msg # pass-through

base/exports.jl

@@ -780,6 +780,7 @@ export
  atreplinit,
  exit,
  ntuple,
+ isdebug,
 
 # I/O and events
  close,

base/loading.jl

@@ -1231,6 +1231,7 @@ function compilecache_path(pkg::PkgId, cache::TOMLCache)::String
  crc = _crc32c(unsafe_string(JLOptions().image_file), crc)
  crc = _crc32c(unsafe_string(JLOptions().julia_bin), crc)
  crc = _crc32c(get_preferences_hash(pkg.uuid, cache), crc)
+ crc = _crc32c(isdebug(), crc)
  project_precompile_slug = slug(crc, 5)
  abspath(cachepath, string(entryfile, "_", project_precompile_slug, ".ji"))
  end
@@ -1358,6 +1359,8 @@ function parse_cache_header(f::IO)
  end
  totbytes -= 4 + 4 + n2 + 8
  end
+ julia_debug = Bool(read(f, UInt8))
+ totbytes -= 1
  prefs_hash = read(f, UInt64)
  totbytes -= 8
  @assert totbytes == 12 "header of cache file appears to be corrupt"
@@ -1372,7 +1375,7 @@ function parse_cache_header(f::IO)
  build_id = read(f, UInt64) # build id
  push!(required_modules, PkgId(uuid, sym) => build_id)
  end
- return modules, (includes, requires), required_modules, srctextpos, prefs_hash
+ return modules, (includes, requires), required_modules, srctextpos, prefs_hash, julia_debug
 end
 
 function parse_cache_header(cachefile::String; srcfiles_only::Bool=false)
@@ -1381,21 +1384,21 @@ function parse_cache_header(cachefile::String; srcfiles_only::Bool=false)
  !isvalid_cache_header(io) && throw(ArgumentError("Invalid header in cache file $cachefile."))
  ret = parse_cache_header(io)
  srcfiles_only || return ret
- modules, (includes, requires), required_modules, srctextpos, prefs_hash = ret
+ modules, (includes, requires), required_modules, srctextpos, prefs_hash, julia_debug = ret
  srcfiles = srctext_files(io, srctextpos)
  delidx = Int[]
  for (i, chi) in enumerate(includes)
  chi.filename ∈ srcfiles || push!(delidx, i)
  end
  deleteat!(includes, delidx)
- return modules, (includes, requires), required_modules, srctextpos, prefs_hash
+ return modules, (includes, requires), required_modules, srctextpos, prefs_hash, julia_debug
  finally
  close(io)
  end
 end
 
 function cache_dependencies(f::IO)
- defs, (includes, requires), modules, srctextpos, prefs_hash = parse_cache_header(f)
+ defs, (includes, requires), modules, srctextpos, prefs_hash, julia_debug = parse_cache_header(f)
  return modules, map(chi -> (chi.filename, chi.mtime), includes) # return just filename and mtime
 end
 
@@ -1410,7 +1413,7 @@ function cache_dependencies(cachefile::String)
 end
 
 function read_dependency_src(io::IO, filename::AbstractString)
- modules, (includes, requires), required_modules, srctextpos, prefs_hash = parse_cache_header(io)
+ modules, (includes, requires), required_modules, srctextpos, prefs_hash, julia_debug = parse_cache_header(io)
  srctextpos == 0 && error("no source-text stored in cache file")
  seek(io, srctextpos)
  return _read_dependency_src(io, filename)
@@ -1496,7 +1499,7 @@ function stale_cachefile(modpath::String, cachefile::String, cache::TOMLCache)
  @debug "Rejecting cache file $cachefile due to it containing an invalid cache header"
  return true # invalid cache file
  end
- modules, (includes, requires), required_modules, srctextpos, prefs_hash = parse_cache_header(io)
+ modules, (includes, requires), required_modules, srctextpos, prefs_hash, julia_debug = parse_cache_header(io)
  id = isempty(modules) ? nothing : first(modules).first
  modules = Dict{PkgId, UInt64}(modules)
 
@@ -1572,6 +1575,11 @@ function stale_cachefile(modpath::String, cachefile::String, cache::TOMLCache)
  end
 
  if isa(id, PkgId)
+ curr_debug = isdebug()
+ if julia_debug != curr_debug
+ @debug "Rejecting cache file $cachefile because julia debug mode does not match"
+ return true
+ end
  curr_prefs_hash = get_preferences_hash(id.uuid, cache)
  if prefs_hash != curr_prefs_hash
  @debug "Rejecting cache file $cachefile because preferences hash does not match 0x$(string(prefs_hash, base=16)) != 0x$(string(curr_prefs_hash, base=16))"

doc/Makefile

@@ -7,7 +7,7 @@ SRCDIR := $(abspath $(dir $(lastword $(MAKEFILE_LIST))))
 JULIAHOME := $(abspath $(SRCDIR)/..)
 SRCCACHE := $(abspath $(JULIAHOME)/deps/srccache)
 include $(JULIAHOME)/Make.inc
-JULIA_EXECUTABLE := $(call spawn,$(build_bindir)/julia) --startup-file=no
+JULIA_EXECUTABLE := $(call spawn,$(build_bindir)/julia) --startup-file=no -g2
 
 .PHONY: help clean cleanall html pdf deps deploy
 

src/dump.c

@@ -1124,6 +1124,14 @@ static int64_t write_dependency_list(ios_t *s, jl_array_t **udepsp, jl_array_t *
  }
  write_int32(s, 0); // terminator, for ease of reading
 
+ // Julia debug mode
+ jl_value_t *julia_debug = (jl_value_t*)jl_get_global(jl_base_module, jl_symbol("julia_debug"));
+ if (julia_debug) {
+ write_int8(s, jl_unbox_bool(julia_debug));
+ } else {
+ write_int8(s, 0);
+ }
+
  // Calculate Preferences hash for current package.
  jl_value_t *prefs_hash = NULL;
  if (jl_base_module) {

test/assert.jl

@@ -0,0 +1,60 @@
+# This file is run from test/misc.jl separately since it needs to run with `-g2`.
+using Test
+
+# test @assert macro
+@test_throws AssertionError (@assert 1 == 2)
+@test_throws AssertionError (@assert false)
+@test_throws AssertionError (@assert false "this is a test")
+@test_throws AssertionError (@assert false "this is a test" "another test")
+@test_throws AssertionError (@assert false :a)
+let
+ try
+ @assert 1 == 2
+ error("unexpected")
+ catch ex
+ @test isa(ex, AssertionError)
+ @test occursin("1 == 2", ex.msg)
+ end
+end
+# test @assert message
+let
+ try
+ @assert 1 == 2 "this is a test"
+ error("unexpected")
+ catch ex
+ @test isa(ex, AssertionError)
+ @test ex.msg == "this is a test"
+ end
+end
+# @assert only uses the first message string
+let
+ try
+ @assert 1 == 2 "this is a test" "this is another test"
+ error("unexpected")
+ catch ex
+ @test isa(ex, AssertionError)
+ @test ex.msg == "this is a test"
+ end
+end
+# @assert calls string() on second argument
+let
+ try
+ @assert 1 == 2 :random_object
+ error("unexpected")
+ catch ex
+ @test isa(ex, AssertionError)
+ @test !occursin("1 == 2", ex.msg)
+ @test occursin("random_object", ex.msg)
+ end
+end
+# if the second argument is an expression, c
+let deepthought(x, y) = 42
+ try
+ @assert 1 == 2 string("the answer to the ultimate question: ",
+ deepthought(6, 9))
+ error("unexpected")
+ catch ex
+ @test isa(ex, AssertionError)
+ @test ex.msg == "the answer to the ultimate question: 42"
+ end
+end

test/errorshow.jl

@@ -332,7 +332,7 @@ let undefvar
  @test err_str == "InterruptException:"
  err_str = @except_str throw(ArgumentError("not an error")) ArgumentError
  @test err_str == "ArgumentError: not an error"
- err_str = @except_str @assert(false) AssertionError
+ err_str = read(`$(Base.julia_cmd()) -g2 -e 'try @assert false; catch e; showerror(stdout, e); end'`, String)
  @test err_str == "AssertionError: false"
 end
 

test/exceptions.jl

@@ -369,6 +369,8 @@ end
 end
 
 # issue #36527
+s = raw"""
+using Test
 function f36527()
  caught = false
  🏡 = Core.eval(Main, :(module asdf36527 end))
@@ -383,6 +385,8 @@ function f36527()
 end
 
 @test f36527()
+"""
+@test success(`$(Base.julia_cmd()) -g2 -e $s`)
 
 # accessing an undefined var in tail position in a catch block
 function undef_var_in_catch()

test/misc.jl

@@ -3,64 +3,8 @@
 isdefined(Main, :FakePTYs) || @eval Main include("testhelpers/FakePTYs.jl")
 
 # Tests that do not really go anywhere else
-
-# test @assert macro
-@test_throws AssertionError (@assert 1 == 2)
-@test_throws AssertionError (@assert false)
-@test_throws AssertionError (@assert false "this is a test")
-@test_throws AssertionError (@assert false "this is a test" "another test")
-@test_throws AssertionError (@assert false :a)
-let
- try
- @assert 1 == 2
- error("unexpected")
- catch ex
- @test isa(ex, AssertionError)
- @test occursin("1 == 2", ex.msg)
- end
-end
-# test @assert message
-let
- try
- @assert 1 == 2 "this is a test"
- error("unexpected")
- catch ex
- @test isa(ex, AssertionError)
- @test ex.msg == "this is a test"
- end
-end
-# @assert only uses the first message string
-let
- try
- @assert 1 == 2 "this is a test" "this is another test"
- error("unexpected")
- catch ex
- @test isa(ex, AssertionError)
- @test ex.msg == "this is a test"
- end
-end
-# @assert calls string() on second argument
-let
- try
- @assert 1 == 2 :random_object
- error("unexpected")
- catch ex
- @test isa(ex, AssertionError)
- @test !occursin("1 == 2", ex.msg)
- @test occursin("random_object", ex.msg)
- end
-end
-# if the second argument is an expression, c
-let deepthought(x, y) = 42
- try
- @assert 1 == 2 string("the answer to the ultimate question: ",
- deepthought(6, 9))
- error("unexpected")
- catch ex
- @test isa(ex, AssertionError)
- @test ex.msg == "the answer to the ultimate question: 42"
- end
-end
+assert_file = joinpath(@__DIR__, "assert.jl")
+@test success(`$(Base.julia_cmd()) -g2 $assert_file`)
 
 let # test the process title functions, issue #9957
  oldtitle = Sys.get_process_title()
@@ -770,19 +714,19 @@ end
 
 @kwdef struct TestInnerConstructor
  a = 1
- TestInnerConstructor(a::Int) = (@assert a>0; new(a))
+ TestInnerConstructor(a::Int) = (a>0 || error(); new(a))
  function TestInnerConstructor(a::String)
- @assert length(a) > 0
+ length(a) > 0 || error()
  new(a)
  end
 end
 
 @testset "@kwdef inner constructor" begin
  @test TestInnerConstructor() == TestInnerConstructor(1)
  @test TestInnerConstructor(a=2) == TestInnerConstructor(2)
- @test_throws AssertionError TestInnerConstructor(a=0)
+ @test_throws ErrorException TestInnerConstructor(a=0)
  @test TestInnerConstructor(a="2") == TestInnerConstructor("2")
- @test_throws AssertionError TestInnerConstructor(a="")
+ @test_throws ErrorException TestInnerConstructor(a="")
 end
 
 const outsidevar = 7
@@ -819,7 +763,7 @@ end
 
 @testset "Pointer to unsigned/signed integer" begin
  # assuming UInt and Ptr have the same size
- @assert sizeof(UInt) == sizeof(Ptr{Nothing})
+ @test sizeof(UInt) == sizeof(Ptr{Nothing})
  uint = UInt(0x12345678)
  sint = signed(uint)
  ptr = reinterpret(Ptr{Nothing}, uint)