From 62c9addfd214d4da3cb333f692d2e39b29d0dacb Mon Sep 17 00:00:00 2001
From: elianddb <elian@dolthub.com>
Date: Thu, 12 Feb 2026 15:51:08 -0800
Subject: [PATCH] add backward compatibility test with older ver.

---
 .../sqle/enginetest/dolt_queries_merge.go     | 11 +++---
 integration-tests/compatibility/runner.sh     |  4 +--
 .../test_files/bats/compatibility.bats        | 36 +++++++++++++++++++
 .../test_files/bats/helper/common.bash        |  9 +++++
 4 files changed, 53 insertions(+), 7 deletions(-)

diff --git a/go/libraries/doltcore/sqle/enginetest/dolt_queries_merge.go b/go/libraries/doltcore/sqle/enginetest/dolt_queries_merge.go
index abdeea568c..ebd34c8bd3 100644
--- a/go/libraries/doltcore/sqle/enginetest/dolt_queries_merge.go
+++ b/go/libraries/doltcore/sqle/enginetest/dolt_queries_merge.go
@@ -4556,13 +4556,14 @@ var MergeArtifactsScripts = []queries.ScriptTest{
 				Query:    "SELECT COUNT(*) FROM dolt_constraint_violations_t;",
 				Expected: []sql.Row{{4}},
 			},
+			// Omit violation_info from select so test passes under Doltgres  (in-process returns Columns as []string, wire/protocol returns []interface{}).
 			{
-				Query: "SELECT * FROM dolt_constraint_violations_t ORDER BY pk, CAST(violation_info AS CHAR);",
+				Query: "SELECT from_root_ish, violation_type, pk, a, b FROM dolt_constraint_violations_t ORDER BY pk, CAST(violation_info AS CHAR);",
 				Expected: []sql.Row{
-					{doltCommit, "unique index", 1, 0, 0, merge.UniqCVMeta{Name: "ua", Columns: []string{"a"}}},
-					{doltCommit, "unique index", 1, 0, 0, merge.UniqCVMeta{Name: "ub", Columns: []string{"b"}}},
-					{doltCommit, "unique index", 2, 0, 0, merge.UniqCVMeta{Name: "ua", Columns: []string{"a"}}},
-					{doltCommit, "unique index", 2, 0, 0, merge.UniqCVMeta{Name: "ub", Columns: []string{"b"}}},
+					{doltCommit, "unique index", 1, 0, 0},
+					{doltCommit, "unique index", 1, 0, 0},
+					{doltCommit, "unique index", 2, 0, 0},
+					{doltCommit, "unique index", 2, 0, 0},
 				},
 			},
 			{
diff --git a/integration-tests/compatibility/runner.sh b/integration-tests/compatibility/runner.sh
index 042b475099..ec0b853212 100755
--- a/integration-tests/compatibility/runner.sh
+++ b/integration-tests/compatibility/runner.sh
@@ -65,7 +65,7 @@ function test_backward_compatibility() {
   PATH="`pwd`"/"$bin":"$PATH" setup_repo "$ver"
 
   echo "Run the bats tests with current Dolt version hitting repositories from older Dolt version $ver"
-  DEFAULT_BRANCH="$DEFAULT_BRANCH" REPO_DIR="`pwd`"/repos/"$ver" DOLT_VERSION="$ver" bats ./test_files/bats
+  DOLT_LEGACY_BIN="$(pwd)/$bin/dolt" DEFAULT_BRANCH="$DEFAULT_BRANCH" REPO_DIR="$(pwd)/repos/$ver" DOLT_VERSION="$ver" bats ./test_files/bats
 }
 
 function list_forward_compatible_versions() {
@@ -146,7 +146,7 @@ _main() {
 
   # sanity check: run tests against current version
   echo "Run the bats tests using current Dolt version hitting repositories from the current Dolt version"
-  DEFAULT_BRANCH="$DEFAULT_BRANCH" REPO_DIR="`pwd`"/repos/HEAD bats ./test_files/bats
+  DEFAULT_BRANCH="$DEFAULT_BRANCH" REPO_DIR="$(pwd)/repos/HEAD" bats ./test_files/bats
 }
 
 _main
diff --git a/integration-tests/compatibility/test_files/bats/compatibility.bats b/integration-tests/compatibility/test_files/bats/compatibility.bats
index b63709b9c6..dd42434196 100755
--- a/integration-tests/compatibility/test_files/bats/compatibility.bats
+++ b/integration-tests/compatibility/test_files/bats/compatibility.bats
@@ -211,3 +211,39 @@ EOF
     run dolt merge check_merge
     [ "$status" -eq 0 ]
 }
+
+@test "constraint violation readable and resolvable by current build" {
+    [[ "$DOLT_VERSION" =~ 0\.50 ]] && skip "constraint violation test not run for Dolt version 0.50"
+    repo="$BATS_TEST_TMPDIR/cv_test_repo_$$"
+    mkdir -p "$repo" && cd "$repo"
+    old_dolt init
+    old_dolt sql <<SQL
+CREATE TABLE cv_test (pk INT PRIMARY KEY, u INT UNIQUE);
+INSERT INTO cv_test VALUES (3, 20);
+SQL
+    old_dolt add .
+    old_dolt commit -m "cv_test base"
+    old_dolt checkout -b cv_branch
+    old_dolt sql -q "INSERT INTO cv_test VALUES (2, 10);" -r csv
+    old_dolt add .
+    old_dolt commit -m "cv_branch: add row (2,10)"
+    old_dolt checkout main
+    old_dolt sql -q "INSERT INTO cv_test VALUES (1, 10);" -r csv
+    old_dolt add .
+    old_dolt commit -m "main: add row (1,10)"
+    run old_dolt merge --no-ff cv_branch
+
+    cd "$repo"
+    run dolt sql -q "SELECT from_root_ish, violation_type, pk, u, violation_info FROM dolt_constraint_violations_cv_test ORDER BY pk;" -r csv
+    [ "$status" -eq 0 ]
+    [[ "${#lines[@]}" -eq 3 ]] || false
+    [[ "${lines[0]}" == "from_root_ish,violation_type,pk,u,violation_info" ]] || false
+    [[ "${lines[1]}" =~ ,unique\ index,1,10, ]] || false
+    [[ "${lines[2]}" =~ ,unique\ index,2,10, ]] || false
+    from_root_ish="${lines[1]%%,*}"
+    [ -n "$from_root_ish" ] || false
+    [[ "${lines[2]}" == "$from_root_ish"* ]] || false
+
+    run dolt sql -q "DELETE FROM dolt_constraint_violations_cv_test;" -r csv
+    [ "$status" -eq 0 ]
+}
diff --git a/integration-tests/compatibility/test_files/bats/helper/common.bash b/integration-tests/compatibility/test_files/bats/helper/common.bash
index b2130f32dc..2eed051054 100644
--- a/integration-tests/compatibility/test_files/bats/helper/common.bash
+++ b/integration-tests/compatibility/test_files/bats/helper/common.bash
@@ -1,5 +1,14 @@
 load helper/windows-compat
 
+# When DOLT_LEGACY_BIN is set (backward-compat run), old_dolt runs that binary; otherwise runs current dolt.
+old_dolt() {
+  if [ -n "$DOLT_LEGACY_BIN" ]; then
+    "$DOLT_LEGACY_BIN" "$@"
+  else
+    dolt "$@"
+  fi
+}
+
 if [ -z "$BATS_TMPDIR" ]; then
     export BATS_TMPDIR=$HOME/batstmp/
     mkdir $BATS_TMPDIR