Query: Adds translation support for single key single value select GR…

…OUP BY LINQ queries (#4074)

* preliminary change

* Add some more boiler plate code

* move all linq test to the same folder; add some groupBy test

* fix references error in test refactoring

add code for group by substitution. Still need to adjust binding post groupby

* preliminary for the groupby functions with key and value selector

* trying to change collection inputs for group by

* WIP bookmark

* Successfully ignore "key"

* clean up code

* Sucessfully bind the case of group by with only key selector and no value selector followed by an optional select clause

* enable one group by test

* add support for aggregate value selector

* added baseline

* working on adding support for multivalue value selector and key selector

* code clean up

* more clean up

* more clean up

* update test

* Move test to separate file

* code clean up

* remove baseline file that got moved

* fix merge issue

* Changes test infrastructure to reflect changes from Master

* address code review part 1

* Address code review 2 and adds code coverage

* Addressed code review and added tests. Still a couple of bugs to iron out

* Fix group by translation issue and add more test

* update comments

* address pr comment

---------

Co-authored-by: Minh Le <leminh@microsoft.com>
Co-authored-by: Aditya <adityasa@users.noreply.github.com>

Microsoft.Azure.Cosmos/src/Linq/TranslationContext.cs

@@ -43,6 +43,16 @@ internal sealed class TranslationContext
  /// </summary>
  public IDictionary<object, string> Parameters;
 
+ /// <summary>
+ /// Dictionary for group by key substitution.
+ /// </summary>
+ public ParameterSubstitution GroupByKeySubstitution;
+
+ /// <summary>
+ /// Boolean to indicate a GroupBy expression is the last expression to finished processing.
+ /// </summary>
+ public bool LastExpressionIsGroupBy;
+
  /// <summary>
  /// If the FROM clause uses a parameter name, it will be substituted for the parameter used in 
  /// the lambda expressions for the WHERE and SELECT clauses.
@@ -86,6 +96,7 @@ public TranslationContext(CosmosLinqSerializerOptionsInternal linqSerializerOpti
  this.subqueryBindingStack = new Stack<SubqueryBinding>();
  this.Parameters = parameters;
  this.clientOperation = null;
+ this.LastExpressionIsGroupBy = false;
 
  if (linqSerializerOptionsInternal?.CustomCosmosLinqSerializer != null)
  {
@@ -104,6 +115,8 @@ public TranslationContext(CosmosLinqSerializerOptionsInternal linqSerializerOpti
  this.CosmosLinqSerializer = TranslationContext.DefaultLinqSerializer;
  this.MemberNames = TranslationContext.DefaultMemberNames;
  }
+
+ this.GroupByKeySubstitution = new ParameterSubstitution();
  }
 
  public ScalarOperationKind ClientOperation => this.clientOperation ?? ScalarOperationKind.None;
@@ -120,17 +133,25 @@ public void SetClientOperation(ScalarOperationKind clientOperation)
 
  public Expression LookupSubstitution(ParameterExpression parameter)
  {
+ if (this.CurrentQuery.GroupByParameter != null)
+ {
+ Expression groupBySubstitutionExpression = this.GroupByKeySubstitution.Lookup(parameter);
+ if (groupBySubstitutionExpression != null)
+ {
+ return groupBySubstitutionExpression;
+ }
+ }
  return this.substitutions.Lookup(parameter);
  }
 
- public ParameterExpression GenFreshParameter(Type parameterType, string baseParameterName)
+ public ParameterExpression GenerateFreshParameter(Type parameterType, string baseParameterName, bool includeSuffix = true)
  {
- return Utilities.NewParameter(baseParameterName, parameterType, this.InScope);
+ return Utilities.NewParameter(baseParameterName, parameterType, this.InScope, includeSuffix);
  }
 
  public Func<string, ParameterExpression> GetGenFreshParameterFunc()
  {
- return (paramName) => this.GenFreshParameter(typeof(object), paramName);
+ return (paramName) => this.GenerateFreshParameter(typeof(object), paramName);
  }
 
  /// <summary>
@@ -211,12 +232,12 @@ public void PushCollection(Collection collection)
  throw new ArgumentNullException("collection");
  }
 
- this.collectionStack.Add(collection);
+ if (this.CurrentQuery.GroupByParameter == null) this.collectionStack.Add(collection);
  }
 
  public void PopCollection()
  {
- this.collectionStack.RemoveAt(this.collectionStack.Count - 1);
+ if (this.CurrentQuery.GroupByParameter == null) this.collectionStack.RemoveAt(this.collectionStack.Count - 1);
  }
 
  /// <summary>
@@ -226,7 +247,7 @@ public void PopCollection()
  /// <param name="name">Suggested name for the input parameter.</param>
  public ParameterExpression SetInputParameter(Type type, string name)
  {
- return this.CurrentQuery.fromParameters.SetInputParameter(type, name, this.InScope);
+ return this.CurrentQuery.FromParameters.SetInputParameter(type, name, this.InScope);
  }
 
  /// <summary>
@@ -237,7 +258,7 @@ public ParameterExpression SetInputParameter(Type type, string name)
  public void SetFromParameter(ParameterExpression parameter, SqlCollection collection)
  {
  Binding binding = new Binding(parameter, collection, isInCollection: true);
- this.CurrentQuery.fromParameters.Add(binding);
+ this.CurrentQuery.FromParameters.Add(binding);
  }
 
  /// <summary>

Microsoft.Azure.Cosmos/src/Linq/Utilities.cs

@@ -45,15 +45,16 @@ public static LambdaExpression GetLambda(Expression expr)
  /// <param name="prefix">Prefix for the parameter name.</param>
  /// <param name="type">Parameter type.</param>
  /// <param name="inScope">Names to avoid.</param>
+ /// <param name="includeSuffix">Enable suffix to parameter name</param>
  /// <returns>The new parameter.</returns>
- public static ParameterExpression NewParameter(string prefix, Type type, HashSet<ParameterExpression> inScope)
+ public static ParameterExpression NewParameter(string prefix, Type type, HashSet<ParameterExpression> inScope, bool includeSuffix = true)
  {
  int suffix = 0;
  while (true)
  {
- string name = prefix + suffix.ToString(CultureInfo.InvariantCulture);
+ string name = prefix + (includeSuffix ? suffix.ToString(CultureInfo.InvariantCulture) : string.Empty);
  ParameterExpression param = Expression.Parameter(type, name);
- if (!inScope.Any(p => p.Name.Equals(name)))
+ if (!inScope.Any(p => p.Name.Equals(name)) || !includeSuffix)
  {
  inScope.Add(param);
  return param;

Microsoft.Azure.Cosmos/src/SqlObjects/Visitors/SqlObjectTextSerializer.cs

@@ -495,6 +495,7 @@ public override void Visit(SqlQuery sqlQuery)
 
  if (sqlQuery.GroupByClause != null)
  {
+ this.WriteDelimiter(string.Empty);
  sqlQuery.GroupByClause.Accept(this);
  this.writer.Write(" ");
  }