From 0ffbae80ea1537fc000283ecdb96618c0e855648 Mon Sep 17 00:00:00 2001
From: Cody Tapscott <84105208+topolarity@users.noreply.github.com>
Date: Thu, 25 Jul 2024 05:42:25 -0400
Subject: [PATCH] TOML: Make `Dates` a type parameter (#55017)

This will allow us to resolve the `Dates` at compile-time eventually. It
also fixes `TOML.Parser()` to return Dates types again.
---
 base/loading.jl                   | 10 +++++---
 base/toml_parser.jl               | 39 +++++++++++++++++--------------
 stdlib/REPL/src/Pkg_beforeload.jl |  4 +++-
 stdlib/TOML/src/TOML.jl           | 22 +++++++----------
 stdlib/TOML/test/values.jl        | 15 ++++++++++++
 5 files changed, 54 insertions(+), 36 deletions(-)

diff --git a/base/loading.jl b/base/loading.jl
index bd985e431e497..a768be286c83d 100644
--- a/base/loading.jl
+++ b/base/loading.jl
@@ -264,11 +264,15 @@ const LOADING_CACHE = Ref{Union{LoadingCache, Nothing}}(nothing)
 LoadingCache() = LoadingCache(load_path(), Dict(), Dict(), Dict(), Set(), Dict(), Dict(), Dict())
 
 
-struct TOMLCache
-    p::TOML.Parser
+struct TOMLCache{Dates}
+    p::TOML.Parser{Dates}
     d::Dict{String, CachedTOMLDict}
 end
-const TOML_CACHE = TOMLCache(TOML.Parser(), Dict{String, Dict{String, Any}}())
+TOMLCache(p::TOML.Parser) = TOMLCache(p, Dict{String, CachedTOMLDict}())
+# TODO: Delete this converting constructor once Pkg stops using it
+TOMLCache(p::TOML.Parser, d::Dict{String, Dict{String, Any}}) = TOMLCache(p, convert(Dict{String, CachedTOMLDict}, d))
+
+const TOML_CACHE = TOMLCache(TOML.Parser{nothing}())
 
 parsed_toml(project_file::AbstractString) = parsed_toml(project_file, TOML_CACHE, require_lock)
 function parsed_toml(project_file::AbstractString, toml_cache::TOMLCache, toml_lock::ReentrantLock)
diff --git a/base/toml_parser.jl b/base/toml_parser.jl
index d50ca3b423c26..cc1455f61928b 100644
--- a/base/toml_parser.jl
+++ b/base/toml_parser.jl
@@ -38,7 +38,7 @@ const TOMLDict  = Dict{String, Any}
 # Parser #
 ##########
 
-mutable struct Parser
+mutable struct Parser{Dates}
     str::String
     # 1 character look ahead
     current_char::Char
@@ -86,12 +86,12 @@ mutable struct Parser
     filepath::Union{String, Nothing}
 
     # Optionally populate with the Dates stdlib to change the type of Date types returned
-    Dates::Union{Module, Nothing}
+    Dates::Union{Module, Nothing} # TODO: remove once Pkg is updated
 end
 
-function Parser(str::String; filepath=nothing)
+function Parser{Dates}(str::String; filepath=nothing) where {Dates}
     root = TOMLDict()
-    l = Parser(
+    l = Parser{Dates}(
             str,                  # str
             EOF_CHAR,             # current_char
             firstindex(str),      # pos
@@ -112,6 +112,7 @@ function Parser(str::String; filepath=nothing)
     startup(l)
     return l
 end
+
 function startup(l::Parser)
     # Populate our one character look-ahead
     c = eat_char(l)
@@ -122,8 +123,10 @@ function startup(l::Parser)
     end
 end
 
-Parser() = Parser("")
-Parser(io::IO) = Parser(read(io, String))
+Parser{Dates}() where {Dates} = Parser{Dates}("")
+Parser{Dates}(io::IO) where {Dates} = Parser{Dates}(read(io, String))
+
+# Parser(...) will be defined by TOML stdlib
 
 function reinit!(p::Parser, str::String; filepath::Union{Nothing, String}=nothing)
     p.str = str
@@ -1021,11 +1024,11 @@ function parse_datetime(l)
     return try_return_datetime(l, year, month, day, h, m, s, ms)
 end
 
-function try_return_datetime(p, year, month, day, h, m, s, ms)
-    Dates = p.Dates
-    if Dates !== nothing
+function try_return_datetime(p::Parser{Dates}, year, month, day, h, m, s, ms) where Dates
+    if Dates !== nothing || p.Dates !== nothing
+        mod = Dates !== nothing ? Dates : p.Dates
         try
-            return Dates.DateTime(year, month, day, h, m, s, ms)
+            return mod.DateTime(year, month, day, h, m, s, ms)
         catch ex
             ex isa ArgumentError && return ParserError(ErrParsingDateTime)
             rethrow()
@@ -1035,11 +1038,11 @@ function try_return_datetime(p, year, month, day, h, m, s, ms)
     end
 end
 
-function try_return_date(p, year, month, day)
-    Dates = p.Dates
-    if Dates !== nothing
+function try_return_date(p::Parser{Dates}, year, month, day) where Dates
+    if Dates !== nothing || p.Dates !== nothing
+        mod = Dates !== nothing ? Dates : p.Dates
         try
-            return Dates.Date(year, month, day)
+            return mod.Date(year, month, day)
         catch ex
             ex isa ArgumentError && return ParserError(ErrParsingDateTime)
             rethrow()
@@ -1058,11 +1061,11 @@ function parse_local_time(l::Parser)
     return try_return_time(l, h, m, s, ms)
 end
 
-function try_return_time(p, h, m, s, ms)
-    Dates = p.Dates
-    if Dates !== nothing
+function try_return_time(p::Parser{Dates}, h, m, s, ms) where Dates
+    if Dates !== nothing || p.Dates !== nothing
+        mod = Dates !== nothing ? Dates : p.Dates
         try
-            return Dates.Time(h, m, s, ms)
+            return mod.Time(h, m, s, ms)
         catch ex
             ex isa ArgumentError && return ParserError(ErrParsingDateTime)
             rethrow()
diff --git a/stdlib/REPL/src/Pkg_beforeload.jl b/stdlib/REPL/src/Pkg_beforeload.jl
index 2051e11711b0f..ebd0cd255ce19 100644
--- a/stdlib/REPL/src/Pkg_beforeload.jl
+++ b/stdlib/REPL/src/Pkg_beforeload.jl
@@ -71,7 +71,9 @@ end
 function projname(project_file::String)
     if isfile(project_file)
         name = try
-            p = Base.TOML.Parser()
+            # The `nothing` here means that this TOML parser does not return proper Dates.jl
+            # objects - but that's OK since we're just checking the name here.
+            p = Base.TOML.Parser{nothing}()
             Base.TOML.reinit!(p, read(project_file, String); filepath=project_file)
             proj = Base.TOML.parse(p)
             get(proj, "name", nothing)
diff --git a/stdlib/TOML/src/TOML.jl b/stdlib/TOML/src/TOML.jl
index 7414b5dc686f4..94d2808c0bc24 100644
--- a/stdlib/TOML/src/TOML.jl
+++ b/stdlib/TOML/src/TOML.jl
@@ -38,16 +38,10 @@ performance if a larger number of small files are parsed.
 """
 const Parser = Internals.Parser
 
-"""
-    DTParser()
-
-Constructor for a TOML `Parser` which returns date and time objects from Dates.
-"""
-function DTParser(args...; kwargs...)
-    parser = Parser(args...; kwargs...)
-    parser.Dates = Dates
-    return parser
-end
+# Dates-enabled constructors
+Parser() = Parser{Dates}()
+Parser(io::IO) = Parser{Dates}(io)
+Parser(str::String; filepath=nothing) = Parser{Dates}(str; filepath)
 
 """
     parsefile(f::AbstractString)
@@ -59,7 +53,7 @@ Parse file `f` and return the resulting table (dictionary). Throw a
 See also [`TOML.tryparsefile`](@ref).
 """
 parsefile(f::AbstractString) =
-    Internals.parse(DTParser(readstring(f); filepath=abspath(f)))
+    Internals.parse(Parser(readstring(f); filepath=abspath(f)))
 parsefile(p::Parser, f::AbstractString) =
     Internals.parse(Internals.reinit!(p, readstring(f); filepath=abspath(f)))
 
@@ -73,7 +67,7 @@ Parse file `f` and return the resulting table (dictionary). Return a
 See also [`TOML.parsefile`](@ref).
 """
 tryparsefile(f::AbstractString) =
-    Internals.tryparse(DTParser(readstring(f); filepath=abspath(f)))
+    Internals.tryparse(Parser(readstring(f); filepath=abspath(f)))
 tryparsefile(p::Parser, f::AbstractString) =
     Internals.tryparse(Internals.reinit!(p, readstring(f); filepath=abspath(f)))
 
@@ -87,7 +81,7 @@ Throw a [`ParserError`](@ref) upon failure.
 See also [`TOML.tryparse`](@ref).
 """
 parse(str::AbstractString) =
-    Internals.parse(DTParser(String(str)))
+    Internals.parse(Parser(String(str)))
 parse(p::Parser, str::AbstractString) =
     Internals.parse(Internals.reinit!(p, String(str)))
 parse(io::IO) = parse(read(io, String))
@@ -103,7 +97,7 @@ Return a [`ParserError`](@ref) upon failure.
 See also [`TOML.parse`](@ref).
 """
 tryparse(str::AbstractString) =
-    Internals.tryparse(DTParser(String(str)))
+    Internals.tryparse(Parser(String(str)))
 tryparse(p::Parser, str::AbstractString) =
     Internals.tryparse(Internals.reinit!(p, String(str)))
 tryparse(io::IO) = tryparse(read(io, String))
diff --git a/stdlib/TOML/test/values.jl b/stdlib/TOML/test/values.jl
index be2ed3acce5b5..4fc49d47fc98d 100644
--- a/stdlib/TOML/test/values.jl
+++ b/stdlib/TOML/test/values.jl
@@ -4,16 +4,31 @@ using Test
 using TOML
 using TOML: Internals
 
+# Construct an explicit Parser to test the "cached" version of parsing
+const test_parser = TOML.Parser()
+
 function testval(s, v)
     f = "foo = $s"
+    # First, test with the standard entrypoint
     parsed = TOML.parse(f)["foo"]
     return isequal(v, parsed) && typeof(v) == typeof(parsed)
+    (!isequal(v, parsed) || typeof(v) != typeof(parsed)) && return false
+    # Next, test with the "cached" (explicit Parser) entrypoint
+    parsed = TOML.parse(test_parser, f)["foo"]
+    (!isequal(v, parsed) || typeof(v) != typeof(parsed)) && return false
+    return true
 end
 
 function failval(s, v)
     f = "foo = $s"
+    # First, test with the standard entrypoint
     err = TOML.tryparse(f);
     return err isa TOML.Internals.ParserError && err.type == v
+    (!isa(err, TOML.Internals.ParserError) || err.type != v) && return false
+    # Next, test with the "cached" (explicit Parser) entrypoint
+    err = TOML.tryparse(test_parser, f);
+    (!isa(err, TOML.Internals.ParserError) || err.type != v) && return false
+    return true
 end
 
 @testset "Numbers" begin