From d7ac4e042f52f19e51016c27e24a8233327bcbcb Mon Sep 17 00:00:00 2001
From: Kevin Gurney <kgurney@mathworks.com>
Date: Wed, 8 Apr 2026 13:42:59 -0400
Subject: [PATCH] Add Feather V1 deprecation warnings to `featherread` and
 `featherwrite`.

Co-authored-by: Sarah Gilmore <sgilmore@mathworks.com>
---
 matlab/src/matlab/featherread.m           |  4 ++++
 matlab/src/matlab/featherwrite.m          |  3 +++
 matlab/test/arrow/io/feather/tRoundTrip.m |  9 +++++++
 matlab/test/tfeather.m                    | 29 +++++++++++++++++++++++
 4 files changed, 45 insertions(+)

diff --git a/matlab/src/matlab/featherread.m b/matlab/src/matlab/featherread.m
index 736fe832888c..b330b8943067 100644
--- a/matlab/src/matlab/featherread.m
+++ b/matlab/src/matlab/featherread.m
@@ -27,6 +27,10 @@
         filename(1, 1) string {mustBeNonmissing, mustBeNonzeroLengthText}
     end
 
+    warning("arrow:io:feather:v1:FeatherReadDeprecated", ...
+        "Reading from Feather V1 files is deprecated. Use arrow.io.ipc.RecordBatchFileReader to read from Feather V2 (Arrow IPC) files.");
+
+
     typesToCast = [arrow.type.ID.UInt8, ...
                    arrow.type.ID.UInt16, ...
                    arrow.type.ID.UInt32, ...
diff --git a/matlab/src/matlab/featherwrite.m b/matlab/src/matlab/featherwrite.m
index 27fa5dfbb389..337ba789620f 100644
--- a/matlab/src/matlab/featherwrite.m
+++ b/matlab/src/matlab/featherwrite.m
@@ -28,6 +28,9 @@ function featherwrite(filename, t)
         t table
     end
 
+    warning("arrow:io:feather:v1:FeatherWriteDeprecated", ...
+        "Writing to Feather V1 files is deprecated. Use arrow.io.ipc.RecordBatchFileWriter to write to Feather V2 (Arrow IPC) files.");
+
     recordBatch = arrow.recordBatch(t);
     writer = arrow.internal.io.feather.Writer(filename);
     writer.write(recordBatch);
diff --git a/matlab/test/arrow/io/feather/tRoundTrip.m b/matlab/test/arrow/io/feather/tRoundTrip.m
index 6fa88d155d9e..a1e576a03f58 100644
--- a/matlab/test/arrow/io/feather/tRoundTrip.m
+++ b/matlab/test/arrow/io/feather/tRoundTrip.m
@@ -16,6 +16,15 @@
 % permissions and limitations under the License.
 classdef tRoundTrip < matlab.unittest.TestCase
 
+    methods(TestMethodSetup)
+
+        function suppressFeatherV1Warnings(testCase)
+            import matlab.unittest.fixtures.SuppressedWarningsFixture
+            testCase.applyFixture(SuppressedWarningsFixture("arrow:io:feather:v1:FeatherReadDeprecated"));
+        end
+
+    end
+
     methods(Test)
         function Basic(testCase)
             import matlab.unittest.fixtures.TemporaryFolderFixture
diff --git a/matlab/test/tfeather.m b/matlab/test/tfeather.m
index b24b6b4af1de..5d3b9c6f6396 100755
--- a/matlab/test/tfeather.m
+++ b/matlab/test/tfeather.m
@@ -22,6 +22,12 @@ function setupTempWorkingDirectory(testCase)
             import matlab.unittest.fixtures.WorkingFolderFixture;
             testCase.applyFixture(WorkingFolderFixture);
         end
+
+        function suppressFeatherV1Warnings(testCase)
+            import matlab.unittest.fixtures.SuppressedWarningsFixture
+            testCase.applyFixture(SuppressedWarningsFixture("arrow:io:feather:v1:FeatherReadDeprecated"));
+            testCase.applyFixture(SuppressedWarningsFixture("arrow:io:feather:v1:FeatherWriteDeprecated"));
+        end
         
     end
     
@@ -267,6 +273,29 @@ function UnicodeVariableNames(testCase)
             testCase.verifyEqual(actualTable, expectedTable);
         end
 
+        function VerifyFeatherReadDeprecationWarning(testCase)
+            filename = fullfile(pwd, 'temp.feather');
+
+            t = array2table([1, 2, 3]);
+            featherwrite(filename, t);
+            
+            warning("on", "arrow:io:feather:v1:FeatherReadDeprecated");
+            fcn = @() featherread(filename);
+            testCase.verifyWarning(fcn, "arrow:io:feather:v1:FeatherReadDeprecated")
+            warning("off", "arrow:io:feather:v1:FeatherReadDeprecated");
+        end
+
+        function VerifyFeatherWriteDeprecationWarning(testCase)
+            filename = fullfile(pwd, 'temp.feather');
+
+            t = array2table([1, 2, 3]);
+            
+            warning("on", "arrow:io:feather:v1:FeatherWriteDeprecated");
+            fcn = @() featherwrite(filename, t);
+            testCase.verifyWarning(fcn, "arrow:io:feather:v1:FeatherWriteDeprecated")
+            warning("off", "arrow:io:feather:v1:FeatherReadDeprecated");
+        end
+
     end
 end