switch DCP warning mechanism

Author: ericphanson

docs/src/advanced.md

@@ -13,11 +13,12 @@ y = Variable()
 x*y
 ```
 
-To disable this, set the module-level parameter `DCP_WARNINGS` via
+To disable this, run
 
 ```julia
-Convex.DCP_WARNINGS[] = false
+Convex.emit_dcp_warnings() = false
 ```
+to redefine the method. See [`Convex.emit_dcp_warnings`](@ref) for more details.
 
 
 Dual Variables

docs/src/reference.md

@@ -24,4 +24,5 @@ Convex.fix!
 Convex.free!
 Convex.evaluate
 Convex.solve!
+Convex.emit_dcp_warnings
 ```

src/Convex.jl

@@ -42,14 +42,17 @@ export add_constraints!, maximize, minimize, Problem, satisfy, solve!
 # Module level globals
 
 """
-    DCP_WARNINGS
+    emit_dcp_warnings
 
 Controls whether or not warnings are emitted for when an expression fails to be
-of disciplined convex form. To turn warnings off, run
+of disciplined convex form. To turn warnings off, override the method via
 
-    Convex.DCP_WARNINGS[] = false
+    Convex.emit_dcp_warnings() = false
+
+This will cause Julia's method invalidation to recompile any functions emitting
+DCP warnings and remove them. This should be run from top-level (not within a function).
 """
-const DCP_WARNINGS = Ref(true)
+emit_dcp_warnings() = true
 
 """
     MAXDEPTH

src/dcp.jl

@@ -21,7 +21,7 @@ struct ConcaveVexity <: Vexity            end
 
 struct NotDcp <: Vexity
     function NotDcp()
-        if DCP_WARNINGS[]
+        if emit_dcp_warnings()
             @warn "Expression not DCP compliant. Trying to solve non-DCP compliant problems can lead to unexpected behavior."
         end
         return new()

test/test_utilities.jl

@@ -440,9 +440,9 @@ end
         # default is to log
         @test_logs (:warn, r"not DCP compliant") Convex.NotDcp()
 
-        Convex.DCP_WARNINGS[] = false
+        @eval Convex.emit_dcp_warnings() = false
         @test_logs  Convex.NotDcp()
-        Convex.DCP_WARNINGS[] = true
+        @eval Convex.emit_dcp_warnings() = true
         @test_logs (:warn, r"not DCP compliant") Convex.NotDcp()
 
     end