From 3340bfb254189ff9e8b9c3089633955134db7527 Mon Sep 17 00:00:00 2001
From: Phillip Alday <palday@users.noreply.github.com>
Date: Tue, 1 Oct 2024 01:00:40 +0000
Subject: [PATCH] fix flipped lower and upper in profile CI (#785)

* fix flipped lower and upper in profile CI

* news link

* thinko

* julia 1.8 compat

* remove debug lines
---
 NEWS.md                |  5 +++++
 Project.toml           |  2 +-
 src/profile/profile.jl | 15 +++++++++++++--
 test/pls.jl            |  6 ++++++
 test/runtests.jl       |  2 ++
 5 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/NEWS.md b/NEWS.md
index 8fc431a7d..84cae83e9 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,3 +1,7 @@
+MixedModels v4.26.1 Release Notes
+==============================
+- lower and upper edges of profile confidence intervals for REML-fitted models are no longer flipped [#785]
+
 MixedModels v4.26.0 Release Notes
 ==============================
 - `issingular` now accepts comparison tolerances through the keyword arguments `atol` and `rtol`. [#783]
@@ -564,3 +568,4 @@ Package dependencies
 [#776]: https://github.com/JuliaStats/MixedModels.jl/issues/776
 [#778]: https://github.com/JuliaStats/MixedModels.jl/issues/778
 [#783]: https://github.com/JuliaStats/MixedModels.jl/issues/783
+[#785]: https://github.com/JuliaStats/MixedModels.jl/issues/785
diff --git a/Project.toml b/Project.toml
index a49022ce7..a08cd0c5f 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,7 +1,7 @@
 name = "MixedModels"
 uuid = "ff71e718-51f3-5ec2-a782-8ffcbfa3c316"
 author = ["Phillip Alday <me@phillipalday.com>", "Douglas Bates <dmbates@gmail.com>", "Jose Bayoan Santiago Calderon <jbs3hp@virginia.edu>"]
-version = "4.26.0"
+version = "4.26.1"
 
 [deps]
 Arrow = "69666777-d1a9-59fb-9406-91d4454c9d45"
diff --git a/src/profile/profile.jl b/src/profile/profile.jl
index ff0b63ada..e3cd52abc 100644
--- a/src/profile/profile.jl
+++ b/src/profile/profile.jl
@@ -73,12 +73,23 @@ function StatsAPI.confint(pr::MixedModelProfile; level::Real=0.95)
     cutoff = sqrt(quantile(Chisq(1), level))
     rev = pr.rev
     syms = sort!(collect(filter(k -> !startswith(string(k), 'θ'), keys(rev))))
-    return DictTable(;
+    dt = DictTable(;
         par=syms,
-        estimate=[rev[s](false) for s in syms],
+        estimate=[rev[s](0) for s in syms],
         lower=[rev[s](-cutoff) for s in syms],
         upper=[rev[s](cutoff) for s in syms],
     )
+
+    # XXX for reasons I don't understand, the reverse spline for REML-models
+    # is flipped for the fixed effects, even though the table of interpolation
+    # points isn't.
+    for i in keys(dt.lower)
+        if dt.lower[i] > dt.upper[i]
+            dt.lower[i], dt.upper[i] = dt.upper[i], dt.lower[i]
+        end
+    end
+
+    return dt
 end
 
 function Base.show(io::IO, mime::MIME"text/plain", pr::MixedModelProfile)
diff --git a/test/pls.jl b/test/pls.jl
index c0a540278..cc84b296e 100644
--- a/test/pls.jl
+++ b/test/pls.jl
@@ -662,6 +662,12 @@ end
             [265.130, 13.576, 28.858, 37.718, 8.753];
             atol=1.e-3)
         @test first(only(filter(r -> r.p == :σ && iszero(r.ζ), pr.tbl)).σ) == last(models(:sleepstudy)).σ
+
+        @testset "REML" begin
+            m = refit!(deepcopy(last(models(:sleepstudy))); progress=false, REML=true)
+            ci = @suppress confint(profile(m))
+            @test all(splat(<), zip(ci.lower, ci.upper))
+        end
     end
     @testset "confint" begin
         ci = confint(last(models(:sleepstudy)))
diff --git a/test/runtests.jl b/test/runtests.jl
index 71c82ce1e..e9413ab42 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -7,6 +7,8 @@ using Test
 import InteractiveUtils: versioninfo
 import LinearAlgebra: BLAS
 
+using Base: splat # necessary for Julia 1.8 compat
+
 # there seem to be processor-specific issues and knowing this is helpful
 @info sprint(versioninfo)
 @info BLAS.get_config()