Give a little more information in dolt_diff_* when there is a pk change

go/libraries/doltcore/sqle/dtables/commit_diff_table.go

@@ -216,7 +216,7 @@ func (dt *CommitDiffTable) LookupPartitions(ctx *sql.Context, i sql.IndexLookup)
 		fromSch:  dt.targetSchema,
 	}
 
-	isDiffable, err := dp.isDiffablePartition(ctx)
+	isDiffable, _, err := dp.isDiffablePartition(ctx)
 	if err != nil {
 		return nil, err
 	}

go/libraries/doltcore/sqle/dtables/diff_table.go

@@ -685,30 +685,39 @@ func (dp DiffPartition) GetRowIter(ctx *sql.Context, ddb *doltdb.DoltDB, joiner
 // isDiffablePartition checks if the commit pair for this partition is "diffable".
 // If the primary key sets changed between the two commits, it may not be
 // possible to diff them.
-func (dp *DiffPartition) isDiffablePartition(ctx *sql.Context) (bool, error) {
+func (dp *DiffPartition) isDiffablePartition(ctx *sql.Context) (simpleDiff bool, fuzzyDiff bool, err error) {
 	// dp.to is nil when a table has been deleted previously. In this case, we return
 	// false, to stop processing diffs, since that previously deleted table is considered
 	// a logically different table and we don't want to mix the diffs together.
 	if dp.to == nil {
-		return false, nil
+		return false, false, nil
 	}
 
 	// dp.from is nil when the to commit created a new table
 	if dp.from == nil {
-		return true, nil
+		return true, false, nil
 	}
 
 	fromSch, err := dp.from.GetSchema(ctx)
 	if err != nil {
-		return false, err
+		return false, false, err
 	}
 
 	toSch, err := dp.to.GetSchema(ctx)
 	if err != nil {
-		return false, err
+		return false, false, err
+	}
+
+	easyDiff := schema.ArePrimaryKeySetsDiffable(dp.from.Format(), fromSch, toSch)
+	if easyDiff {
+		return true, false, nil
 	}
 
-	return schema.ArePrimaryKeySetsDiffable(dp.from.Format(), fromSch, toSch), nil
+	_, _, err = schema.MapSchemaBasedOnTagAndName(fromSch, toSch)
+	if err == nil {
+		return false, true, nil
+	}
+	return false, false, nil
 }
 
 type partitionSelectFunc func(*sql.Context, DiffPartition) (bool, error)
@@ -762,6 +771,7 @@ type DiffPartitions struct {
 	selectFunc      partitionSelectFunc
 	toSch           schema.Schema
 	fromSch         schema.Schema
+	stopNext        bool
 }
 
 // processCommit is called in a commit iteration loop. Adds partitions when it finds a commit and its parent that have
@@ -821,6 +831,10 @@ func (dps *DiffPartitions) processCommit(ctx *sql.Context, cmHash hash.Hash, cm
 }
 
 func (dps *DiffPartitions) Next(ctx *sql.Context) (sql.Partition, error) {
+	if dps.stopNext {
+		return nil, io.EOF
+	}
+
 	for {
 		cmHash, optCmt, err := dps.cmItr.Next(ctx)
 		if err != nil {
@@ -852,16 +866,21 @@ func (dps *DiffPartitions) Next(ctx *sql.Context) (sql.Partition, error) {
 
 		if next != nil {
 			// If we can't diff this commit with its parent, don't traverse any lower
-			canDiff, err := next.isDiffablePartition(ctx)
+			simpleDiff, fuzzyDiff, err := next.isDiffablePartition(ctx)
 			if err != nil {
 				return nil, err
 			}
 
-			if !canDiff {
+			if !simpleDiff && !fuzzyDiff {
 				ctx.Warn(PrimaryKeyChangeWarningCode, fmt.Sprintf(PrimaryKeyChangeWarning, next.fromName, next.toName))
 				return nil, io.EOF
 			}
 
+			if !simpleDiff && fuzzyDiff {
+				ctx.Warn(PrimaryKeyChangeWarningCode, fmt.Sprintf(PrimaryKeyChangeWarning, next.fromName, next.toName))
+				dps.stopNext = true
+			}
+
 			return *next, nil
 		}
 	}

go/libraries/doltcore/sqle/dtables/prolly_row_conv.go

@@ -115,10 +115,14 @@ func (c ProllyRowConverter) putFields(ctx context.Context, tup val.Tuple, proj v
 	virtualOffset := 0
 	for i, j := range proj {
 		if j == -1 {
-			// Skip over virtual columns in non-pk cols as they are not stored
-			if !isPk && c.inSchema.GetNonPKCols().GetByIndex(i).Virtual {
-				virtualOffset++
+			nonPkCols := c.inSchema.GetNonPKCols()
+			if len(nonPkCols.GetColumns()) > i {
+				// Skip over virtual columns in non-pk cols as they are not stored
+				if !isPk && nonPkCols.GetByIndex(i).Virtual {
+					virtualOffset++
+				}
 			}
+
 			continue
 		}
 

go/libraries/doltcore/sqle/enginetest/dolt_queries_diff.go

@@ -528,14 +528,44 @@ var DiffSystemTableScriptTests = []queries.ScriptTest{
 			},
 			{
 				Query:    "SELECT COUNT(*) FROM DOLT_DIFF_t;",
-				Expected: []sql.Row{{1}},
+				Expected: []sql.Row{{7}},
 			},
 			{
 				Query:    "SELECT to_pk, to_c1, from_pk, from_c1, diff_type FROM DOLT_DIFF_t where to_commit=@Commit4;",
 				Expected: []sql.Row{{7, 8, nil, nil, "added"}},
 			},
 		},
 	},
+	{
+		// Similar to previous test, but with one row to avoid ordering issues.
+		Name: "altered keyless table add pk", // https://github.com/dolthub/dolt/issues/8625
+		SetUpScript: []string{
+			"create table tbl (i int, j int);",
+			"insert into tbl values (42, 23);",
+			"call dolt_commit('-Am', 'commit1');",
+			"alter table tbl add primary key(i);",
+			"call dolt_commit('-am', 'commit2');",
+		},
+		Assertions: []queries.ScriptTestAssertion{
+			{
+				Query: "SELECT to_i,to_j,from_i,from_j,diff_type  FROM dolt_diff_tbl;",
+				// Output in the situation is admittedly wonky. Updating the PK leaves in a place where we can't really render
+				// the diff, but we want to show something. In this case, the 'pk' column tag changes, so in the last two rows
+				// of the output you see we add "nil,23" and remove "nil,23" when in fact those columns were "42" with a different
+				// tag.
+				//
+				// In the past we just returned an empty set in this case. The
+				// warning is kind of essential to understand what is happening.
+				Expected: []sql.Row{
+					{42, 23, nil, nil, "added"},
+					{nil, nil, nil, 23, "removed"},
+				},
+				ExpectedWarningsCount:           1,
+				ExpectedWarning:                 1105,
+				ExpectedWarningMessageSubstring: "due to primary key set change",
+			},
+		},
+	},
 	{
 		Name: "table with commit column should maintain its data in diff",
 		SetUpScript: []string{
@@ -713,8 +743,10 @@ var Dolt1DiffSystemTableScripts = []queries.ScriptTest{
 		},
 		Assertions: []queries.ScriptTestAssertion{
 			{
-				Query:    "SELECT to_pk1, to_pk2, from_pk1, from_pk2, diff_type from dolt_diff_t;",
-				Expected: []sql.Row{{"2", "2", nil, nil, "added"}},
+				Query: "SELECT to_pk1, to_pk2, from_pk1, from_pk2, diff_type from dolt_diff_t;",
+				Expected: []sql.Row{
+					{"2", "2", nil, nil, "added"},
+				},
 			},
 		},
 	},
@@ -5298,6 +5330,7 @@ var CommitDiffSystemTableScriptTests = []queries.ScriptTest{
 			},
 		},
 	},
+
 	{
 		Name: "added and dropped table",
 		SetUpScript: []string{

integration-tests/bats/sql-diff.bats

@@ -591,7 +591,10 @@ SQL
     done
 }
 
-@test "sql-diff: supports multiple primary keys" {
+run_2pk5col_ints() {
+    local query_name=$1
+
+    # Initial setup
     dolt checkout -b firstbranch
     dolt sql <<SQL
 CREATE TABLE test (
@@ -605,40 +608,56 @@ CREATE TABLE test (
   PRIMARY KEY (pk1,pk2)
 );
 SQL
-    dolt table import -u test `batshelper 2pk5col-ints.csv`
+    dolt table import -u test $(batshelper 2pk5col-ints.csv)
     dolt add .
     dolt commit -m "create/init table test"
-
-    # for each query file in helper/queries/2pk5col-ints/
-    # run query on db, create sql diff patch, confirm they're equivalent
     dolt branch newbranch
-    for query in delete add update single_pk_update all_pk_update create_table
-    do
-        dolt checkout newbranch
-        dolt sql < $BATS_TEST_DIRNAME/helper/queries/2pk5col-ints/$query.sql
-        dolt add .
-        dolt diff -r sql
-        dolt commit -m "applied $query query "
 
-        # confirm a difference exists
+    # Apply the query
+    dolt checkout newbranch
+    dolt sql < "$BATS_TEST_DIRNAME/helper/queries/2pk5col-ints/${query_name}.sql"
+    dolt add .
+    dolt diff -r sql
+    dolt commit -m "applied ${query_name} query"
 
-        run dolt diff -r sql firstbranch newbranch
-        [ "$status" -eq 0 ]
-        [ ! "$output" = "" ]
+    # Confirm a difference exists
+    run dolt diff -r sql firstbranch newbranch
+    [ "$status" -eq 0 ]
+    [ ! "$output" = "" ]
 
-        dolt diff -r sql firstbranch > patch.sql newbranch
-        dolt checkout firstbranch
-        dolt sql < patch.sql
-        rm patch.sql
-        dolt add .
-        dolt commit -m "Reconciled with newbranch"
+    # Generate patch, apply on firstbranch, and verify no differences
+    dolt diff -r sql firstbranch > patch.sql newbranch
+    dolt checkout firstbranch
+    dolt sql < patch.sql
+    rm patch.sql
+    dolt add .
+    dolt commit -m "Reconciled with newbranch"
 
-        # confirm that both branches have the same content
-        run dolt diff -r sql firstbranch newbranch
-        [ "$status" -eq 0 ]
-        [ "$output" = "" ]
-    done
+    # Confirm branches are identical
+    run dolt diff -r sql firstbranch newbranch
+    [ "$status" -eq 0 ]
+    [ "$output" = "" ]
+}
+
+@test "sql-diff: supports multiple primary keys (delete)" {
+    run_2pk5col_ints "delete"
+}
+@test "sql-diff: supports multiple primary keys (add)" {
+    run_2pk5col_ints "add"
 }
+@test "sql-diff: supports multiple primary keys (update)" {
+    run_2pk5col_ints "update"
+}
+@test "sql-diff: supports multiple primary keys (single_pk_update)" {
+    run_2pk5col_ints "single_pk_update"
+}
+@test "sql-diff: supports multiple primary keys (all_pk_update)" {
+    run_2pk5col_ints "all_pk_update"
+}
+@test "sql-diff: supports multiple primary keys (create_table)" {
+    run_2pk5col_ints "create_table"
+}
+
 
 @test "sql-diff: escapes values for MySQL string literals" {
     # https://dev.mysql.com/doc/refman/8.0/en/string-literals.html