From 935cda79b9ba6be6d86fc3725075cfdab980dfb2 Mon Sep 17 00:00:00 2001
From: ChrisRackauckas <me@chrisrackauckas.com>
Date: Sun, 28 Sep 2025 17:25:21 -0400
Subject: [PATCH 1/2] Add error handling for vector expressions
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Fixes #58 and #106 by throwing an informative error when vector expressions are passed to integrate().

The error message guides users to use element-wise integration instead: integrate.([expr1, expr2, ...], x)

Added tests to verify:
- Vector expressions throw appropriate error
- Scalar integration still works
- Element-wise integration works as expected

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>
---
 simple_test.jl     | 31 ++++++++++++++++++++++++++++++
 src/integral.jl    |  5 +++++
 test/runtests.jl   | 18 ++++++++++++++++++
 test_vector_fix.jl | 47 ++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 101 insertions(+)
 create mode 100644 simple_test.jl
 create mode 100644 test_vector_fix.jl

diff --git a/simple_test.jl b/simple_test.jl
new file mode 100644
index 0000000..9f35772
--- /dev/null
+++ b/simple_test.jl
@@ -0,0 +1,31 @@
+using Pkg
+Pkg.activate(".")
+
+# Force load the package
+using SymbolicNumericIntegration
+using Symbolics
+
+println("Testing vector expression error handling...")
+
+# Test case 1: Vector with symbolic variables
+@variables x
+try
+    result = integrate([x])
+    println("❌ Test 1 FAILED: Should have thrown an error but got: $result")
+catch e
+    if occursin("Vector expressions are not supported", string(e))
+        println("✅ Test 1 PASSED: Vector input correctly rejected")
+    else
+        println("❌ Test 1 FAILED: Wrong error message: $(e)")
+    end
+end
+
+# Test case 2: Scalar integration should still work
+try
+    result = integrate(x)
+    println("✅ Test 2 PASSED: Scalar integration works: $result")
+catch e
+    println("❌ Test 2 FAILED: Scalar integration should work but got: $(e)")
+end
+
+println("\nAll tests completed!")
\ No newline at end of file
diff --git a/src/integral.jl b/src/integral.jl
index 04f9d04..3db34da 100644
--- a/src/integral.jl
+++ b/src/integral.jl
@@ -72,6 +72,11 @@ function integrate(eq, x = nothing;
         detailed = true)
     deprecation_warnings(; homotopy, use_optim)
 
+    # Check if eq is a vector/array expression and throw an error
+    if eq isa AbstractArray || eq isa AbstractVector
+        error("Vector expressions are not supported. Please use element-wise integration with `integrate.([expr1, expr2, ...], x)` instead.")
+    end
+
     eq = expand(eq)
 
     if x == nothing
diff --git a/test/runtests.jl b/test/runtests.jl
index b4bc8a2..f2c14db 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -327,3 +327,21 @@ end
         num_trials = 10)
     @test n > 0
 end
+
+@testset "vector expression error handling" begin
+    @variables x α
+
+    # Test that vector expressions throw an appropriate error
+    @test_throws ErrorException("Vector expressions are not supported. Please use element-wise integration with `integrate.([expr1, expr2, ...], x)` instead.") integrate([x])
+    @test_throws ErrorException("Vector expressions are not supported. Please use element-wise integration with `integrate.([expr1, expr2, ...], x)` instead.") integrate([1, 2 * α], α)
+
+    # Test that scalar integration still works
+    @test integrate(x) == ((1//2)*(x^2), 0, 0)
+    @test integrate(2 * α, α) == (α^2, 0, 0)
+
+    # Test that element-wise integration works
+    results = integrate.([1, 2 * α], α)
+    @test length(results) == 2
+    @test results[1] == (α, 0, 0)
+    @test results[2] == (α^2, 0, 0)
+end
diff --git a/test_vector_fix.jl b/test_vector_fix.jl
new file mode 100644
index 0000000..593aa67
--- /dev/null
+++ b/test_vector_fix.jl
@@ -0,0 +1,47 @@
+using Pkg
+Pkg.activate(".")
+using Symbolics, SymbolicNumericIntegration
+
+println("Testing vector expression error handling:")
+println()
+
+# Test case from issue #58
+@variables α
+exp2 = [1, 2 * α]
+
+println("Test 1: integrate([1, 2α], α)")
+try
+    result = integrate(exp2, α)
+    println("ERROR: Should have thrown an error but got: $result")
+catch e
+    println("✓ Correctly caught error: $(e)")
+end
+
+println()
+println("Test 2: Verify element-wise integration still works")
+try
+    result = integrate.(exp2, α)
+    println("✓ Element-wise integration works: $result")
+catch e
+    println("ERROR: Element-wise should work but got: $(e)")
+end
+
+println()
+# Test case from issue #106
+@variables x
+println("Test 3: integrate([x])")
+try
+    result = integrate([x])
+    println("ERROR: Should have thrown an error but got: $result")
+catch e
+    println("✓ Correctly caught error: $(e)")
+end
+
+println()
+println("Test 4: Verify scalar integration still works")
+try
+    result = integrate(2 * α, α)
+    println("✓ Scalar integration works: $result")
+catch e
+    println("ERROR: Scalar should work but got: $(e)")
+end
\ No newline at end of file

From 708e3205a937ecc41e1278e52db49d7f4a7ab5b2 Mon Sep 17 00:00:00 2001
From: ChrisRackauckas <me@chrisrackauckas.com>
Date: Sun, 28 Sep 2025 17:26:46 -0400
Subject: [PATCH 2/2] Clean up temporary test files

---
 simple_test.jl     | 31 ------------------------------
 test_vector_fix.jl | 47 ----------------------------------------------
 2 files changed, 78 deletions(-)
 delete mode 100644 simple_test.jl
 delete mode 100644 test_vector_fix.jl

diff --git a/simple_test.jl b/simple_test.jl
deleted file mode 100644
index 9f35772..0000000
--- a/simple_test.jl
+++ /dev/null
@@ -1,31 +0,0 @@
-using Pkg
-Pkg.activate(".")
-
-# Force load the package
-using SymbolicNumericIntegration
-using Symbolics
-
-println("Testing vector expression error handling...")
-
-# Test case 1: Vector with symbolic variables
-@variables x
-try
-    result = integrate([x])
-    println("❌ Test 1 FAILED: Should have thrown an error but got: $result")
-catch e
-    if occursin("Vector expressions are not supported", string(e))
-        println("✅ Test 1 PASSED: Vector input correctly rejected")
-    else
-        println("❌ Test 1 FAILED: Wrong error message: $(e)")
-    end
-end
-
-# Test case 2: Scalar integration should still work
-try
-    result = integrate(x)
-    println("✅ Test 2 PASSED: Scalar integration works: $result")
-catch e
-    println("❌ Test 2 FAILED: Scalar integration should work but got: $(e)")
-end
-
-println("\nAll tests completed!")
\ No newline at end of file
diff --git a/test_vector_fix.jl b/test_vector_fix.jl
deleted file mode 100644
index 593aa67..0000000
--- a/test_vector_fix.jl
+++ /dev/null
@@ -1,47 +0,0 @@
-using Pkg
-Pkg.activate(".")
-using Symbolics, SymbolicNumericIntegration
-
-println("Testing vector expression error handling:")
-println()
-
-# Test case from issue #58
-@variables α
-exp2 = [1, 2 * α]
-
-println("Test 1: integrate([1, 2α], α)")
-try
-    result = integrate(exp2, α)
-    println("ERROR: Should have thrown an error but got: $result")
-catch e
-    println("✓ Correctly caught error: $(e)")
-end
-
-println()
-println("Test 2: Verify element-wise integration still works")
-try
-    result = integrate.(exp2, α)
-    println("✓ Element-wise integration works: $result")
-catch e
-    println("ERROR: Element-wise should work but got: $(e)")
-end
-
-println()
-# Test case from issue #106
-@variables x
-println("Test 3: integrate([x])")
-try
-    result = integrate([x])
-    println("ERROR: Should have thrown an error but got: $result")
-catch e
-    println("✓ Correctly caught error: $(e)")
-end
-
-println()
-println("Test 4: Verify scalar integration still works")
-try
-    result = integrate(2 * α, α)
-    println("✓ Scalar integration works: $result")
-catch e
-    println("ERROR: Scalar should work but got: $(e)")
-end
\ No newline at end of file