Add detailed error messaging when dolt_ignore rules conflict.

go/cmd/dolt/commands/add.go

@@ -127,7 +127,21 @@ func toAddVErr(err error) errhand.VerboseError {
 		}
 
 		return bdr.Build()
+	case doltdb.IsDoltIgnoreInConflict(err):
+		tbl := doltdb.DoltIgnoreConflictTableName(err)
+		truePatterns := doltdb.DoltIgnoreConflictTruePatterns(err)
+		falsePatterns := doltdb.DoltIgnoreConflictFalsePatterns(err)
+		bdr := errhand.BuildDError("error: the table %s matches conflicting patterns in dolt_ignore", tbl)
 
+		for _, pattern := range truePatterns {
+			bdr.AddDetails("ignored:     %s", pattern)
+		}
+
+		for _, pattern := range falsePatterns {
+			bdr.AddDetails("not ignored: %s", pattern)
+		}
+
+		return bdr.Build()
 	default:
 		return errhand.BuildDError("Unknown error").AddCause(err).Build()
 	}

go/libraries/doltcore/doltdb/errors.go

@@ -170,3 +170,48 @@ func GetUnreachableRootCause(err error) error {
 
 	return rvu.Cause
 }
+
+type DoltIgnoreConflict struct {
+	Table         string
+	TruePatterns  []string
+	FalsePatterns []string
+}
+
+func (dc DoltIgnoreConflict) Error() string {
+	return fmt.Sprintf("dolt_ignore has multiple conflicting rules for %s", dc.Table)
+}
+
+func IsDoltIgnoreInConflict(err error) bool {
+	_, ok := err.(DoltIgnoreConflict)
+	return ok
+}
+
+func DoltIgnoreConflictTableName(err error) string {
+	dc, ok := err.(DoltIgnoreConflict)
+
+	if !ok {
+		panic("Must validate with IsDoltIgnoreInConflict before calling DoltIgnoreConflictTableName")
+	}
+
+	return dc.Table
+}
+
+func DoltIgnoreConflictTruePatterns(err error) []string {
+	dc, ok := err.(DoltIgnoreConflict)
+
+	if !ok {
+		panic("Must validate with IsDoltIgnoreInConflict before calling DoltIgnoreConflictTruePatterns")
+	}
+
+	return dc.TruePatterns
+}
+
+func DoltIgnoreConflictFalsePatterns(err error) []string {
+	dc, ok := err.(DoltIgnoreConflict)
+
+	if !ok {
+		panic("Must validate with IsDoltIgnoreInConflict before calling DoltIgnoreConflictFalsePatterns")
+	}
+
+	return dc.FalsePatterns
+}

go/libraries/doltcore/doltdb/ignore_patterns.go

@@ -137,7 +137,25 @@ func resolveConflictingPatterns(trueMatches, falseMatches []string, tableName st
 	if len(falseMatchesToRemove) == len(falseMatches) {
 		return true, nil
 	}
-	return false, fmt.Errorf("dolt_ignore has multiple conflicting rules for %s", tableName)
+
+	// There's a conflict. Remove the less specific patterns so that only the conflict remains.
+
+	var conflictingTrueMatches []string
+	var conflictingFalseMatches []string
+
+	for _, trueMatch := range trueMatches {
+		if _, ok := trueMatchesToRemove[trueMatch]; !ok {
+			conflictingTrueMatches = append(conflictingTrueMatches, trueMatch)
+		}
+	}
+
+	for _, falseMatch := range falseMatches {
+		if _, ok := trueMatchesToRemove[falseMatch]; !ok {
+			conflictingFalseMatches = append(conflictingFalseMatches, falseMatch)
+		}
+	}
+
+	return false, DoltIgnoreConflict{Table: tableName, TruePatterns: conflictingTrueMatches, FalsePatterns: conflictingFalseMatches}
 }
 
 func (ip *IgnorePatterns) IsTableNameIgnored(tableName string) (bool, error) {