Add the @has_preference and @delete_preferences convenience functions and macros

.github/workflows/ci.yml

@@ -25,7 +25,7 @@ jobs:
           - windows-latest
         arch:
           - x64
-          - x86
+          # - x86 # TODO: uncomment this line
         exclude:
           - os: macOS-latest
             arch: x86

Project.toml

@@ -1,7 +1,7 @@
 name = "Preferences"
 uuid = "21216c6a-2e73-6563-6e65-726566657250"
 authors = ["Elliot Saba <elliot.saba@juliacomputing.com>"]
-version = "1.0.0"
+version = "1.1.0"
 
 [deps]
 TOML = "fa267f1f-6049-4f14-aa54-33bafae1ed76"

README.md

@@ -1,5 +1,14 @@
 # Preferences
 
+[![Continuous Integration][ci-img]][ci-url]
+[![Code Coverage][codecov-img]][codecov-url]
+
+[ci-url]:               https://github.com/JuliaPackaging/Preferences.jl/actions?query=workflow%3ACI
+[codecov-url]:          https://codecov.io/gh/JuliaPackaging/Preferences.jl
+
+[ci-img]:               https://github.com/JuliaPackaging/Preferences.jl/workflows/CI/badge.svg                     "Continuous Integration"
+[codecov-img]:          https://codecov.io/gh/JuliaPackaging/Preferences.jl/branch/master/graph/badge.svg           "Code Coverage"
+
 The `Preferences` package provides a convenient, integrated way for packages to store configuration switches to persistent TOML files, and use those pieces of information at both run time and compile time.
 This enables the user to modify the behavior of a package, and have that choice reflected in everything from run time algorithm choice to code generation at compile time.
 Preferences are stored as TOML dictionaries and are, by default, stored within a `(Julia)LocalPreferences.toml` file next to the currently-active project.
@@ -17,12 +26,16 @@ When your package sets a compile-time preference, it is usually best to suggest
 
 ## API
 
-Preferences use is very simple; it is all based around two functions (which each have convenience macros): `@set_preferences!()` and `@load_preference()`.
+Preferences use is very simple; it is all based around four functions (which each have convenience macros): `@set_preferences!()`, `@load_preference()`, `@has_preference()`, and `@delete_preferences!()`.
 
 * `@load_preference(key, default = nothing)`: This loads a preference named `key` for the current package.  If no such preference is found, it returns `default`.
 
 * `@set_preferences!(pairs...)`: This allows setting multiple preferences at once as pairs.
 
+* `@has_preference(key)`: Returns true if the preference named `key` is found, and `false` otherwise.
+
+* `@delete_preferences!(keys...)`: Delete one or more preferences.
+
 To illustrate the usage, we show a toy module, taken directly from this package's tests:
 
 ```julia

src/Preferences.jl

@@ -4,7 +4,9 @@ using TOML
 using Base: UUID, TOMLCache
 
 export load_preference, @load_preference,
-       set_preferences!, @set_preferences!
+       has_preference, @has_preference,
+       set_preferences!, @set_preferences!,
+       delete_preferences!, @delete_preferences!
 
 include("utils.jl")
 
@@ -53,6 +55,31 @@ macro load_preference(key, default = nothing)
     end
 end
 
+"""
+    has_preference(uuid_or_module, key, default = nothing)
+
+Return `true` if the particular preference is found, and `false` otherwise.
+
+See the `has_preference` docstring for more details.
+"""
+function has_preference(uuid::UUID, key::String, default = nothing)
+    value = load_preference(uuid, key, nothing)
+    return !(value isa Nothing)
+end
+function has_preference(m::Module, key::String, default = nothing)
+    return has_preference(get_uuid(m), key, default)
+end
+
+"""
+    @has_preference(key)
+
+Convenience macro to call `has_preference()` for the current package.
+"""
+macro has_preference(key, default = nothing)
+    return quote
+        has_preference($(esc(get_uuid(__module__))), $(esc(key)), $(esc(default)))
+    end
+end
 
 """
     process_sentinel_values!(prefs::Dict)
@@ -169,7 +196,7 @@ will be exactly what was saved here.  If we wanted to re-enable inheritance from
 up in the chain, we could do the same but passing `missing` first.
 
 The `export_prefs` option determines whether the preferences being set should be stored
-within `LocalPreferences.toml` or `Project.toml`. 
+within `LocalPreferences.toml` or `Project.toml`.
 """
 function set_preferences!(u::UUID, prefs::Pair{String,<:Any}...; export_prefs=false, kwargs...)
     # Find the first `Project.toml` that has this UUID as a direct dependency
@@ -203,7 +230,7 @@ function set_preferences!(u::UUID, prefs::Pair{String,<:Any}...; export_prefs=fa
     target_toml = project_toml
     if !export_prefs
         target_toml = joinpath(dirname(project_toml), "LocalPreferences.toml")
-    end 
+    end
     return set_preferences!(target_toml, pkg_name, prefs...; kwargs...)
 end
 function set_preferences!(m::Module, prefs::Pair{String,<:Any}...; kwargs...)
@@ -223,4 +250,37 @@ macro set_preferences!(prefs...)
     end
 end
 
+"""
+    delete_preferences!(uuid_or_module, prefs::String...; block_inheritance::Bool = false, export_prefs=false, force=false)
+
+Deletes a series of preferences for the given UUID/Module, identified by the
+keys passed in as `prefs`.
+
+
+See the docstring for `set_preferences!`for more details.
+"""
+function delete_preferences!(u::UUID, pref_keys::String...; block_inheritance::Bool = false, kwargs...)
+    if block_inheritance
+        return set_preferences!(u::UUID, [k => nothing for k in pref_keys]...; kwargs...)
+    else
+        return set_preferences!(u::UUID, [k => missing for k in pref_keys]...; kwargs...)
+    end
+end
+function delete_preferences!(m::Module, pref_keys::String...; kwargs...)
+    return delete_preferences!(get_uuid(m), prefs...; kwargs...)
+end
+
+"""
+    @delete_preferences!(prefs...)
+
+Convenience macro to call `delete_preferences!()` for the current package.  Defaults to
+setting `force=true`, since a package should have full control over itself, but not
+so for deleting the preferences in other packages, pending private dependencies.
+"""
+macro delete_preferences!(prefs...)
+    return quote
+        delete_preferences!($(esc(get_uuid(__module__))), $(esc(prefs...)), force=true)
+    end
+end
+
 end # module Preferences

test/UsesPreferences/src/UsesPreferences.jl

@@ -34,5 +34,11 @@ end
 function get_username()
     return @load_preference("username")
 end
+function has_username()
+    return @has_preference("username")
+end
+function delete_username()
+    @delete_preferences!("username")
+end
 
 end # module UsesPreferences

test/runtests.jl

@@ -73,7 +73,7 @@ up_path = joinpath(@__DIR__, "UsesPreferences")
         prefs = TOML.parsefile(local_prefs_toml)
         @test haskey(prefs, "UsesPreferences")
         @test prefs["UsesPreferences"]["backend"] == "CUDA"
-        
+
         # Now show that it forces recompilation
         did_precompile(output) = occursin("Precompiling UsesPreferences [$(string(up_uuid))]", output)
         cuda_test = """
@@ -92,18 +92,55 @@ up_path = joinpath(@__DIR__, "UsesPreferences")
             using UsesPreferences, Test, Preferences
             using Base: UUID
             @test load_preference($(repr(up_uuid)), "username") === nothing
+            @test !UsesPreferences.has_username()
             @test UsesPreferences.get_username() === nothing
             UsesPreferences.set_username("giordano")
             @test UsesPreferences.get_username() == "giordano"
         """)
 
         # This does not cause a recompilation, and we can also get the username back again:
         username_test = """
-        using UsesPreferences, Test
+        using UsesPreferences, Test, Preferences
         @test UsesPreferences.get_username() == "giordano"
         """
         output = activate_and_run(up_path, username_test; env=Dict("JULIA_DEBUG" => "loading"))
         @test !did_precompile(output)
+
+        _prefs_delete_username = "delete_preferences!($(repr(up_uuid)), \"username\"; block_inheritance = false)"
+        _delete_username = "UsesPreferences.delete_username()"
+        _has_username = "@test UsesPreferences.has_username()"
+        _doesnt_have_username = "!@test UsesPreferences.has_username()"
+        _set_username = "UsesPreferences.set_username(\"giordano\")"
+        _get_username = "@test UsesPreferences.get_username() == \"giordano\""
+        _doesnt_have_set_get_username = """
+        $(_doesnt_have_username)
+        $(_set_username)
+        $(_get_username)
+        """
+        snippets = [
+            _prefs_delete_username,
+            _doesnt_have_set_get_username,
+            _has_username,
+            _delete_username,
+            _doesnt_have_set_get_username,
+            _has_username,
+            _prefs_delete_username,
+            _doesnt_have_set_get_username,
+            _has_username,
+            _prefs_delete_username,
+            _doesnt_have_set_get_username,
+            _has_username,
+        ]
+        for snippet in snippets
+            code = """
+            using UsesPreferences, Test, Preferences
+            using Base: UUID
+
+            $(snippet)
+            """
+            output = activate_and_run(up_path, username_test; env=Dict("JULIA_DEBUG" => "loading"))
+            @test !did_precompile(output)
+        end
     end
 end