implement getfield overloading

New functions `Base.getproperty` and `Base.setproperty!`
can be overloaded to change the behavior of `x.f` and `x.f = v`,
respectively.

fix #16226 (close #16195)
fix #1974

Author: vtjnash

base/boot.jl

@@ -149,6 +149,9 @@ export
     # constants
     nothing, Main
 
+const getproperty = getfield
+const setproperty! = setfield!
+
 abstract type Number end
 abstract type Real     <: Number end
 abstract type AbstractFloat <: Real end

base/coreimg.jl

@@ -1,9 +1,12 @@
 # This file is a part of Julia. License is MIT: https://julialang.org/license
 
-Main.Core.eval(Main.Core, :(baremodule Inference
+getfield(getfield(Main, :Core), :eval)(getfield(Main, :Core), :(baremodule Inference
 using Core.Intrinsics
 import Core: print, println, show, write, unsafe_write, STDOUT, STDERR
 
+const getproperty = getfield
+const setproperty! = setfield!
+
 ccall(:jl_set_istopmod, Void, (Any, Bool), Inference, false)
 
 eval(x) = Core.eval(Inference, x)

base/distributed/cluster.jl

@@ -486,7 +486,7 @@ function launch_n_additional_processes(manager, frompid, fromconfig, cnt, launch
 
             wconfig = WorkerConfig()
             for x in [:host, :tunnel, :sshflags, :exeflags, :exename, :enable_threaded_blas]
-                setfield!(wconfig, x, getfield(fromconfig, x))
+                Base.setproperty!(wconfig, x, Base.getproperty(fromconfig, x))
             end
             wconfig.bind_addr = bind_addr
             wconfig.port = port

base/exports.jl

@@ -916,6 +916,8 @@ export
 
 # types
     convert,
+    # getproperty,
+    # setproperty!,
     fieldoffset,
     fieldname,
     fieldnames,

base/libgit2/gitcredential.jl

@@ -130,7 +130,7 @@ function Base.read!(io::IO, cred::GitCredential)
             # https://git-scm.com/docs/git-credential#git-credential-codeurlcode
             copy!(cred, parse(GitCredential, value))
         else
-            setfield!(cred, Symbol(key), Nullable(String(value)))
+            Base.setproperty!(cred, Symbol(key), Nullable(String(value)))
         end
     end
 

base/show.jl

@@ -139,7 +139,7 @@ function show_default(io::IO, @nospecialize(x))
                 if !isdefined(x, f)
                     print(io, undef_ref_str)
                 else
-                    show(recur_io, getfield(x, f))
+                    show(recur_io, getfield(x, i))
                 end
                 if i < nf
                     print(io, ", ")

base/sysimg.jl

@@ -5,6 +5,16 @@ baremodule Base
 using Core.Intrinsics
 ccall(:jl_set_istopmod, Void, (Any, Bool), Base, true)
 
+getproperty(x, f::Symbol) = getfield(x, f)
+setproperty!(x, f::Symbol, v) = setfield!(x, f, convert(fieldtype(typeof(x), f), v))
+
+# Try to help prevent users from shooting them-selves in the foot
+# with ambiguities by defining a few common and critical operations
+getproperty(x::Module, f::Symbol) = getfield(x, f)
+setproperty!(x::Module, f::Symbol, v) = setfield!(x, f, v)
+getproperty(x::Type, f::Symbol) = getfield(x, f)
+setproperty!(x::Type, f::Symbol, v) = setfield!(x, f, v)
+
 function include(mod::Module, path::AbstractString)
     local result
     if INCLUDE_STATE === 1

src/julia-syntax.scm

@@ -1752,7 +1752,7 @@
     (if (and (pair? e) (eq? (car e) '|.|))
         (let ((f (cadr e)) (x (caddr e)))
           (cond ((or (eq? (car x) 'quote) (eq? (car x) 'inert) (eq? (car x) '$))
-                 `(call (core getfield) ,f ,x))
+                 `(call (top getproperty) ,f ,x))
                 ((eq? (car x) 'tuple)
                  (make-fuse f (cdr x)))
                 (else
@@ -2039,10 +2039,12 @@
                 ,.(if (eq? aa a)   '() `((= ,aa ,(expand-forms a))))
                 ,.(if (eq? bb b)   '() `((= ,bb ,(expand-forms b))))
                 ,.(if (eq? rr rhs) '() `((= ,rr ,(expand-forms rhs))))
-                (call (core setfield!) ,aa ,bb
-                      (call (top convert)
-                            (call (core fieldtype) (call (core typeof) ,aa) ,bb)
-                            ,rr))
+                (call (top setproperty!) ,aa ,bb
+                      (if (call (top ===) (top setproperty!) (core setfield!))
+                          (call (top convert)
+                                (call (core fieldtype) (call (core typeof) ,aa) ,bb)
+                                ,rr)
+                          ,rr))
                 (unnecessary ,rr)))))
          ((tuple)
           ;; multiple assignment

src/method.c

@@ -39,41 +39,6 @@ static jl_value_t *resolve_globals(jl_value_t *expr, jl_module_t *module, jl_sve
             // ignore these
         }
         else {
-            if (e->head == call_sym && jl_expr_nargs(e) == 3 &&
-                    jl_is_quotenode(jl_exprarg(e, 2)) && module != NULL) {
-                // replace getfield(module_expr, :sym) with GlobalRef
-                jl_value_t *s = jl_fieldref(jl_exprarg(e, 2), 0);
-                jl_value_t *fe = jl_exprarg(e, 0);
-                if (jl_is_symbol(s) && jl_is_globalref(fe)) {
-                    jl_binding_t *b = jl_get_binding(jl_globalref_mod(fe), jl_globalref_name(fe));
-                    jl_value_t *f = NULL;
-                    if (b && b->constp) {
-                        f = b->value;
-                    }
-                    if (f == jl_builtin_getfield) {
-                        jl_value_t *me = jl_exprarg(e, 1);
-                        jl_module_t *me_mod = NULL;
-                        jl_sym_t *me_sym = NULL;
-                        if (jl_is_globalref(me)) {
-                            me_mod = jl_globalref_mod(me);
-                            me_sym = jl_globalref_name(me);
-                        }
-                        else if (jl_is_symbol(me) && jl_binding_resolved_p(module, (jl_sym_t*)me)) {
-                            me_mod = module;
-                            me_sym = (jl_sym_t*)me;
-                        }
-                        if (me_mod && me_sym) {
-                            jl_binding_t *b = jl_get_binding(me_mod, me_sym);
-                            if (b && b->constp) {
-                                jl_value_t *m = b->value;
-                                if (m && jl_is_module(m)) {
-                                    return jl_module_globalref((jl_module_t*)m, (jl_sym_t*)s);
-                                }
-                            }
-                        }
-                    }
-                }
-            }
             size_t i = 0, nargs = jl_array_len(e->args);
             if (e->head == foreigncall_sym) {
                 JL_NARGSV(ccall method definition, 5); // (fptr, rt, at, cc, narg)
@@ -119,6 +84,29 @@ static jl_value_t *resolve_globals(jl_value_t *expr, jl_module_t *module, jl_sve
                 // TODO: this should be making a copy, not mutating the source
                 jl_exprargset(e, i, resolve_globals(jl_exprarg(e, i), module, sparam_vals, binding_effects));
             }
+            if (e->head == call_sym && jl_expr_nargs(e) == 3 &&
+                    jl_is_globalref(jl_exprarg(e, 0)) &&
+                    jl_is_globalref(jl_exprarg(e, 1)) &&
+                    jl_is_quotenode(jl_exprarg(e, 2))) {
+                // replace module_expr.sym with GlobalRef(module, sym)
+                // for expressions pattern-matching to `getproperty(module_expr, :sym)` in a top-module
+                // (this is expected to help inference performance)
+                jl_value_t *s = jl_fieldref(jl_exprarg(e, 2), 0);
+                jl_value_t *me = jl_exprarg(e, 1);
+                jl_value_t *fe = jl_exprarg(e, 0);
+                jl_module_t *fe_mod = jl_globalref_mod(fe);
+                jl_sym_t *fe_sym = jl_globalref_name(fe);
+                jl_module_t *me_mod = jl_globalref_mod(me);
+                jl_sym_t *me_sym = jl_globalref_name(me);
+                if (fe_mod->istopmod && !strcmp(jl_symbol_name(fe_sym), "getproperty") && jl_is_symbol(s)) {
+                    if (jl_binding_resolved_p(me_mod, me_sym)) {
+                        jl_binding_t *b = jl_get_binding(me_mod, me_sym);
+                        if (b && b->constp && b->value && jl_is_module(b->value)) {
+                            return jl_module_globalref((jl_module_t*)b->value, (jl_sym_t*)s);
+                        }
+                    }
+                }
+            }
         }
     }
     return expr;

test/core.jl

@@ -997,19 +997,21 @@ end
 
 let
     local z = complex(3, 4)
-    v = Int[0,0]
-    for i=1:2
+    v = Int[0, 0]
+    for i = 1:2
         v[i] = getfield(z, i)
     end
-    @test v == [3,4]
-    @test_throws BoundsError getfield(z, -1)
-    @test_throws BoundsError getfield(z, 0)
-    @test_throws BoundsError getfield(z, 3)
+    @test v == [3, 4]
+    @test_throws BoundsError(z, -1) getfield(z, -1)
+    @test_throws BoundsError(z, 0) getfield(z, 0)
+    @test_throws BoundsError(z, 3) getfield(z, 3)
 
     strct = LoadError("yofile", 0, "bad")
-    @test_throws BoundsError getfield(strct, 10)
-    @test_throws ErrorException setfield!(strct, 0, "")
-    @test_throws ErrorException setfield!(strct, 4, "")
+    @test nfields(strct) == 3 # sanity test
+    @test_throws BoundsError(strct, 10) getfield(strct, 10)
+    @test_throws ErrorException("type LoadError is immutable") setfield!(strct, 0, "")
+    @test_throws ErrorException("type LoadError is immutable") setfield!(strct, 4, "")
+    @test_throws ErrorException("type is immutable") setfield!(strct, :line, 0)
     @test strct.file == "yofile"
     @test strct.line == 0
     @test strct.error == "bad"
@@ -1018,15 +1020,17 @@ let
     @test getfield(strct, 3) == "bad"
 
     mstrct = TestMutable("melm", 1, nothing)
-    setfield!(mstrct, 2, 8)
+    Base.setproperty!(mstrct, :line, 8.0)
     @test mstrct.line == 8
+    @test_throws TypeError(:setfield!, "", Int, 8.0) setfield!(mstrct, :line, 8.0)
+    @test_throws TypeError(:setfield!, "", Int, 8.0) setfield!(mstrct, 2, 8.0)
     setfield!(mstrct, 3, "hi")
     @test mstrct.error == "hi"
     setfield!(mstrct, 1, "yo")
     @test mstrct.file == "yo"
-    @test_throws BoundsError getfield(mstrct, 10)
-    @test_throws BoundsError setfield!(mstrct, 0, "")
-    @test_throws BoundsError setfield!(mstrct, 4, "")
+    @test_throws BoundsError(mstrct, 10) getfield(mstrct, 10)
+    @test_throws BoundsError(mstrct, 0) setfield!(mstrct, 0, "")
+    @test_throws BoundsError(mstrct, 4) setfield!(mstrct, 4, "")
 end
 
 # allow typevar in Union to match as long as the arguments contain
@@ -2175,10 +2179,9 @@ g7652() = fieldtype(DataType, :types)
 h7652() = setfield!(a7652, 1, 2)
 h7652()
 @test a7652.a == 2
-# commented out due to issue #16195: setfield! does not perform conversions
-#   i7652() = setfield!(a7652, 1, 3.0)
-#   i7652()
-#   @test a7652.a == 3
+i7652() = Base.setproperty!(a7652, :a, 3.0)
+i7652()
+@test a7652.a == 3
 
 # issue #7679
 @test map(f->f(), Any[ ()->i for i=1:3 ]) == Any[1,2,3]
@@ -2358,49 +2361,53 @@ let
 end
 
 # pull request #9534
-@test try; a,b,c = 1,2; catch ex; (ex::BoundsError).a === (1,2) && ex.i == 3; end
-# @test try; [][]; catch ex; isempty((ex::BoundsError).a::Array{Any,1}) && ex.i == (1,); end # TODO: Re-enable after PLI
-@test try; [][1,2]; catch ex; isempty((ex::BoundsError).a::Array{Any,1}) && ex.i == (1,2); end
-@test try; [][10]; catch ex; isempty((ex::BoundsError).a::Array{Any,1}) && ex.i == (10,); end
-f9534a() = (a=1+2im; getfield(a, -100))
-f9534a(x) = (a=1+2im; getfield(a, x))
-@test try; f9534a() catch ex; (ex::BoundsError).a === 1+2im && ex.i == -100; end
-@test try; f9534a(3) catch ex; (ex::BoundsError).a === 1+2im && ex.i == 3; end
-f9534b() = (a=(1,2.,""); a[5])
-f9534b(x) = (a=(1,2.,""); a[x])
-@test try; f9534b() catch ex; (ex::BoundsError).a == (1,2.,"") && ex.i == 5; end
-@test try; f9534b(4) catch ex; (ex::BoundsError).a == (1,2.,"") && ex.i == 4; end
-f9534c() = (a=(1,2.); a[3])
-f9534c(x) = (a=(1,2.); a[x])
-@test try; f9534c() catch ex; (ex::BoundsError).a === (1,2.) && ex.i == 3; end
-@test try; f9534c(0) catch ex; (ex::BoundsError).a === (1,2.) && ex.i == 0; end
-f9534d() = (a=(1,2,4,6,7); a[7])
-f9534d(x) = (a=(1,2,4,6,7); a[x])
-@test try; f9534d() catch ex; (ex::BoundsError).a === (1,2,4,6,7) && ex.i == 7; end
-@test try; f9534d(-1) catch ex; (ex::BoundsError).a === (1,2,4,6,7) && ex.i == -1; end
-f9534e(x) = (a=IOBuffer(); setfield!(a, x, 3))
-@test try; f9534e(-2) catch ex; isa((ex::BoundsError).a,Base.IOBuffer) && ex.i == -2; end
-f9534f() = (a=IOBuffer(); getfield(a, -2))
-f9534f(x) = (a=IOBuffer(); getfield(a, x))
-@test try; f9534f() catch ex; isa((ex::BoundsError).a,Base.IOBuffer) && ex.i == -2; end
-@test try; f9534f(typemin(Int)+2) catch ex; isa((ex::BoundsError).a,Base.IOBuffer) && ex.i == typemin(Int)+2; end
+@test_throws BoundsError((1, 2), 3) begin; a, b, c = 1, 2; end
+let a = []
+    @test_broken try; a[]; catch ex; (ex::BoundsError).a === a && ex.i == (1,); end # TODO: Re-enable after PLI
+    @test_throws BoundsError(a, (1, 2)) a[1, 2]
+    @test_throws BoundsError(a, (10,)) a[10]
+end
+f9534a() = (a = 1 + 2im; getfield(a, -100))
+f9534a(x) = (a = 1 + 2im; getfield(a, x))
+@test_throws BoundsError(1 + 2im, -100) f9534a()
+@test_throws BoundsError(1 + 2im, 3) f9534a(3)
+f9534b() = (a = (1, 2., ""); a[5])
+f9534b(x) = (a = (1, 2., ""); a[x])
+@test_throws BoundsError((1, 2., ""), 5) f9534b()
+@test_throws BoundsError((1, 2., ""), 4) f9534b(4)
+f9534c() = (a = (1, 2.); a[3])
+f9534c(x) = (a = (1, 2.); a[x])
+@test_throws BoundsError((1, 2.), 3) f9534c()
+@test_throws BoundsError((1, 2.), 0) f9534c(0)
+f9534d() = (a = (1, 2, 4, 6, 7); a[7])
+f9534d(x) = (a = (1, 2, 4, 6, 7); a[x])
+@test_throws BoundsError((1, 2, 4, 6, 7), 7) f9534d()
+@test_throws BoundsError((1, 2, 4, 6, 7), -1) f9534d(-1)
+let a = IOBuffer()
+    f9534e(x) = setfield!(a, x, 3)
+    @test_throws BoundsError(a, -2) f9534e(-2)
+    f9534f() = getfield(a, -2)
+    f9534f(x) = getfield(a, x)
+    @test_throws BoundsError(a, -2) f9534f()
+    @test_throws BoundsError(a, typemin(Int) + 2) f9534f(typemin(Int) + 2)
+end
 x9634 = 3
-@test try; getfield(1+2im, x9634); catch ex; (ex::BoundsError).a === 1+2im && ex.i == 3; end
-@test try; throw(BoundsError()) catch ex; !isdefined((ex::BoundsError), :a) && !isdefined((ex::BoundsError), :i); end
-@test try; throw(BoundsError(Int)) catch ex; (ex::BoundsError).a == Int && !isdefined((ex::BoundsError), :i); end
-@test try; throw(BoundsError(Int, typemin(Int))) catch ex; (ex::BoundsError).a == Int && (ex::BoundsError).i == typemin(Int); end
-@test try; throw(BoundsError(Int, (:a,))) catch ex; (ex::BoundsError).a == Int && (ex::BoundsError).i == (:a,); end
-f9534g(a,b,c...) = c[0]
-@test try; f9534g(1,2,3,4,5,6) catch ex; (ex::BoundsError).a === (3,4,5,6) && ex.i == 0; end
-f9534h(a,b,c...) = c[a]
-@test f9534h(4,2,3,4,5,6) == 6
-@test try; f9534h(5,2,3,4,5,6) catch ex; (ex::BoundsError).a === (3,4,5,6) && ex.i == 5; end
+@test_throws BoundsError(1 + 2im, 3) getfield(1 + 2im, x9634)
+@test try; throw(BoundsError()); catch ex; !isdefined((ex::BoundsError), :a) && !isdefined((ex::BoundsError), :i); end
+@test try; throw(BoundsError(Int)); catch ex; (ex::BoundsError).a == Int && !isdefined((ex::BoundsError), :i); end
+@test_throws BoundsError(Int, typemin(Int)) throw(BoundsError(Int, typemin(Int)))
+@test_throws BoundsError(Int, (:a,)) throw(BoundsError(Int, (:a,)))
+f9534g(a, b, c...) = c[0]
+@test_throws BoundsError((3, 4, 5, 6), 0) f9534g(1, 2, 3, 4, 5, 6)
+f9534h(a, b, c...) = c[a]
+@test f9534h(4, 2, 3, 4, 5, 6) == 6
+@test_throws BoundsError((3, 4, 5, 6), 5) f9534h(5, 2, 3, 4, 5, 6)
 
 # issue #7978, comment 332352438
 f7978a() = 1
-@test try; a, b = f7978a() catch ex; (ex::BoundsError).a == 1 && ex.i == 2; end
+@test_throws BoundsError(1, 2) begin; a, b = f7978a(); end
 f7978b() = 1, 2
-@test try; a, b, c = f7978b() catch ex; (ex::BoundsError).a == (1, 2) && ex.i == 3; end
+@test_throws BoundsError((1, 2), 3) begin; a, b, c = f7978b(); end
 
 # issue #9535
 counter9535 = 0