hack a fix for ListComprehensionExpression.

vesoft-inc · Dec 15, 2022 · 5c6de3b · 5c6de3b
1 parent dffa71f
commit 5c6de3b
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Showing 3 changed files with 34 additions and 3 deletions.
diff --git a/src/common/expression/AttributeExpression.cpp b/src/common/expression/AttributeExpression.cpp
@@ -27,7 +27,28 @@ const Value &AttributeExpression::eval(ExpressionContext &ctx) {
         result_ = lvalue.getVertex().vid;
         return result_;
       }
-      LOG(ERROR) << "Var.tar.prop cannot be evaluated as an attribute expression.";
+      /*
+       * WARNING: the following code snippet is a hardcode to address the legacy
+       * problem of treating LabelTagProperty expressions as Attribute expressions.
+       * It is needed to allow users to write ver.tag.prop in ListComprehensionExpression.
+       */
+      if (left()->kind() == Expression::Kind::kVar) {
+        return lvalue;
+      } else if (left()->kind() == Expression::Kind::kAttribute &&
+                 dynamic_cast<AttributeExpression *>(left())->right()->kind() ==
+                     Expression::Kind::kConstant) {
+        auto &tagName = dynamic_cast<AttributeExpression *>(left())->right()->eval(ctx).getStr();
+        for (auto &tag : lvalue.getVertex().tags) {
+          if (tagName.compare(tag.name) != 0) {
+            continue;
+          } else {
+            auto iter = tag.props.find(rvalue.getStr());
+            if (iter != tag.props.end()) {
+              return iter->second;
+            }
+          }
+        }
+      }
       return Value::kNullBadType;
     }
     case Value::Type::EDGE: {

diff --git a/src/graph/util/ParserUtil.cpp b/src/graph/util/ParserUtil.cpp
@@ -7,6 +7,7 @@
 #include "common/base/ObjectPool.h"
 #include "common/base/Status.h"
 #include "common/base/StatusOr.h"
+#include "graph/util/ExpressionUtils.h"
 
 namespace nebula {
 namespace graph {

diff --git a/src/graph/validator/MatchValidator.cpp b/src/graph/validator/MatchValidator.cpp
@@ -473,8 +473,17 @@ Status MatchValidator::validateReturn(MatchReturn *ret,
           ExpressionUtils::hasAny(column->expr(), {Expression::Kind::kAggregate})) {
         retClauseCtx.yield->hasAgg_ = true;
       }
-      column->setExpr(ExpressionUtils::rewriteAttr2LabelTagProp(
-          column->expr(), retClauseCtx.yield->aliasesAvailable));
+      if (column->expr()->kind() == Expression::Kind::kListComprehension) {
+        auto expr = dynamic_cast<ListComprehensionExpression *>(column->expr());
+        if (expr->hasMapping()) {
+          expr->setMapping(ExpressionUtils::rewriteAttr2LabelTagProp(
+              expr->mapping(), retClauseCtx.yield->aliasesAvailable));
+          column->setExpr(expr);
+        }
+      } else {
+        column->setExpr(ExpressionUtils::rewriteAttr2LabelTagProp(
+            column->expr(), retClauseCtx.yield->aliasesAvailable));
+      }
       exprs.push_back(column->expr());
       columns->addColumn(column->clone().release());
     }