From 0cbb3b49189901cf6d5b292fe9ef54da92ca6a95 Mon Sep 17 00:00:00 2001
From: Johannes Terblanche <Affie@users.noreply.github.com>
Date: Tue, 19 May 2026 10:31:18 +0200
Subject: [PATCH 1/2] Enhance error handling in FactorDFG and VariableDFG
 constructors; ensure unique variable orders and proper tag initialization

---
 src/entities/Factor.jl   | 14 ++++++++++++++
 src/entities/Variable.jl |  1 +
 src/services/compare.jl  |  6 +++++-
 3 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/src/entities/Factor.jl b/src/entities/Factor.jl
index e5af5d04..5a31f1cc 100644
--- a/src/entities/Factor.jl
+++ b/src/entities/Factor.jl
@@ -128,6 +128,20 @@ function FactorDFG(
         timestamp = TimeDateZone(timestamp.utc_datetime)
     end
 
+    #TODO move to core constructor
+    if !isempty(multihypo) && length(multihypo) != length(variableorder)
+        throw(
+            ArgumentError(
+                "multihypo length ($(length(multihypo))) must match the number of variables ($(length(variableorder))). " *
+                "See fractional data-association uncertainty docs.",
+            ),
+        )
+    end
+    if length(variableorder) == 1 && observation isa AbstractRelativeObservation
+        throw(ArgumentError("Relative observation $(typeof(observation)) requires at least two variables, but only one was provided: $variableorder. Use a subtype of AbstractPriorObservation for single-variable factors."))
+    end
+    allunique(variableorder) || throw(ArgumentError("Variable order must be unique, got duplicates in $variableorder"))
+
     # create factor data
     hyper = Recipehyper(; multihypo, nullhypo, inflation)
     state = Recipestate()
diff --git a/src/entities/Variable.jl b/src/entities/Variable.jl
index 71e22328..b4d18ca6 100644
--- a/src/entities/Variable.jl
+++ b/src/entities/Variable.jl
@@ -124,6 +124,7 @@ function VariableDFG(
     if solvable isa Int
         solvable = Ref(solvable)
     end
+    tags = tags isa Set ? tags : Set{Symbol}(tags)
     union!(tags, [:VARIABLE])
 
     P = getPointType(T)
diff --git a/src/services/compare.jl b/src/services/compare.jl
index 20a25a68..33ee3b7b 100644
--- a/src/services/compare.jl
+++ b/src/services/compare.jl
@@ -215,7 +215,11 @@ function compareVariable(
     union!(skiplist, skip)
     # TP = TP && compareAll(A.states, B.states; skip = skiplist, show = show)
 
-    Ad = getState(A, :default) #FIXME why onlly comparing default?
+    #FIXME why only comparing hardcoded default?
+    if !hasState(A, :default) && !hasState(B, :default)
+        return false
+    end
+    Ad = getState(A, :default) 
     Bd = getState(B, :default)
 
     # TP = TP && compareAll(A.attributes, B.attributes, skip=[:variableType;], show=show)

From aed72dd7aa2718879e1feeb0b2f0d1a06626d1ab Mon Sep 17 00:00:00 2001
From: Johannes Terblanche <Affie@users.noreply.github.com>
Date: Tue, 19 May 2026 10:33:32 +0200
Subject: [PATCH 2/2] format

---
 src/entities/Factor.jl  | 10 ++++++++--
 src/services/compare.jl |  2 +-
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/src/entities/Factor.jl b/src/entities/Factor.jl
index 5a31f1cc..843fb09e 100644
--- a/src/entities/Factor.jl
+++ b/src/entities/Factor.jl
@@ -138,9 +138,15 @@ function FactorDFG(
         )
     end
     if length(variableorder) == 1 && observation isa AbstractRelativeObservation
-        throw(ArgumentError("Relative observation $(typeof(observation)) requires at least two variables, but only one was provided: $variableorder. Use a subtype of AbstractPriorObservation for single-variable factors."))
+        throw(
+            ArgumentError(
+                "Relative observation $(typeof(observation)) requires at least two variables, but only one was provided: $variableorder. Use a subtype of AbstractPriorObservation for single-variable factors.",
+            ),
+        )
     end
-    allunique(variableorder) || throw(ArgumentError("Variable order must be unique, got duplicates in $variableorder"))
+    allunique(variableorder) || throw(
+        ArgumentError("Variable order must be unique, got duplicates in $variableorder"),
+    )
 
     # create factor data
     hyper = Recipehyper(; multihypo, nullhypo, inflation)
diff --git a/src/services/compare.jl b/src/services/compare.jl
index 33ee3b7b..6d6516ac 100644
--- a/src/services/compare.jl
+++ b/src/services/compare.jl
@@ -219,7 +219,7 @@ function compareVariable(
     if !hasState(A, :default) && !hasState(B, :default)
         return false
     end
-    Ad = getState(A, :default) 
+    Ad = getState(A, :default)
     Bd = getState(B, :default)
 
     # TP = TP && compareAll(A.attributes, B.attributes, skip=[:variableType;], show=show)