From cf0c2856eebc047fc5bae014a7d8ee6b94062b26 Mon Sep 17 00:00:00 2001
From: Penelope Yong <penelopeysm@gmail.com>
Date: Fri, 26 Jun 2026 17:05:06 +0100
Subject: [PATCH] Update is_binaryop_nestable to be compatible with
 JuliaSyntax@1

---
 HISTORY_v2.md             | 4 ++++
 Project.toml              | 2 +-
 src/styles/blue/pretty.jl | 4 +++-
 test/issues.jl            | 9 +++++++++
 4 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/HISTORY_v2.md b/HISTORY_v2.md
index 04f88eb11..a3fb5c329 100644
--- a/HISTORY_v2.md
+++ b/HISTORY_v2.md
@@ -1,3 +1,7 @@
+# v2.10.1
+
+Fixed a formatting regression for BlueStyle introduced in 2.5.0. (#1013, #1193)
+
 # v2.10.0
 
 Added a new formatting option, `max_iterations`, which controls the number of rounds of formatting that JuliaFormatter will apply.
diff --git a/Project.toml b/Project.toml
index 25f11dd80..e8b4b688f 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,6 +1,6 @@
 name = "JuliaFormatter"
 uuid = "98e50ef6-434e-11e9-1051-2b60c6c9e899"
-version = "2.10.0"
+version = "2.10.1"
 authors = ["Dominique Luna <dluna132@gmail.com> and contributors"]
 
 [workspace]
diff --git a/src/styles/blue/pretty.jl b/src/styles/blue/pretty.jl
index d807d0e26..18b44ec81 100644
--- a/src/styles/blue/pretty.jl
+++ b/src/styles/blue/pretty.jl
@@ -38,7 +38,9 @@ function is_binaryop_nestable(::BlueStyle, cst::JuliaSyntax.GreenNode)
     # don't, there are idempotence issues because on the second pass this will return true.
     # This is a massive pain to do though.
     # See https://github.com/JuliaEditorSupport/JuliaFormatter.jl/issues/1175
-    if is_assignment(cst) && haschildren(cst) && is_iterable(cst[end])
+    if (is_assignment(cst) || defines_function(cst)) &&
+       haschildren(cst) &&
+       is_iterable(cst[end])
         return false
     end
     return is_binaryop_nestable(DefaultStyle(), cst)
diff --git a/test/issues.jl b/test/issues.jl
index 9b9877c3d..6fc9b513e 100644
--- a/test/issues.jl
+++ b/test/issues.jl
@@ -2520,6 +2520,15 @@ end
         end
     end
 
+    @testset "1013" begin
+        s = "check_constraints(ex::Union{AbstractExpression,AbstractExpressionNode}, options::AbstractOptions)::Bool = check_constraints(ex, options, options.maxsize)"
+        out = """
+        check_constraints(ex::Union{AbstractExpression,AbstractExpressionNode}, options::AbstractOptions)::Bool = check_constraints(
+            ex, options, options.maxsize
+        )"""
+        test_format(s, out, BlueStyle())
+    end
+
     @testset "1025" begin
         # from julia@1.12.6 Compiler/src/typelimits.jl
         s = """