From: Tomas Babej <tomas@tbabej.com>
Date: Sat, 30 Jan 2021 17:50:58 -0500
Subject: Backport parser issues fixes

This backports upstream PR #2405 and commit a5eee5f, which contain extra
fixes and tests for issues with numeric project names (amongst others)
which were being wrongly interpreted as expressions.

Addresses upstream issues TW-{2388,2386,2257,1908,1896}
---

diff --git a/src/CLI2.cpp b/src/CLI2.cpp
index ec2bd6c7..c49eb4d7 100644
--- a/src/CLI2.cpp
+++ b/src/CLI2.cpp
@@ -1277,7 +1277,9 @@ void CLI2::desugarFilterAttributes ()
         A2 op ("", Lexer::Type::op);
         op.tag ("FILTER");
 
-        A2 rhs ("", values[0]._lextype);
+        // Attribute types that do not support evaluation should be interpreted
+        // as strings (currently this means that string attributes are not evaluated)
+        A2 rhs ("", evalSupported ? values[0]._lextype: Lexer::Type::string);
         rhs.tag ("FILTER");
 
         // Special case for '<name>:<value>'.
@@ -1371,7 +1373,7 @@ void CLI2::desugarFilterAttributes ()
 
         // Do not modify this construct without full understanding.
         // Getting this wrong breaks a whole lot of filtering tests.
-        if (values.size () > 1 || evalSupported)
+        if (evalSupported)
         {
           for (auto& v : values)
             reconstructed.push_back (v);
@@ -1946,6 +1948,41 @@ void CLI2::desugarFilterPlainArgs ()
 }
 
 ////////////////////////////////////////////////////////////////////////////////
+// Detects if the bracket at iterator it is a start or end of an empty paren expression
+// Examples:
+// ( status = pending ) ( )
+//                      ^
+//              it -----|         => true
+//
+// ( status = pending ) ( project = Home )
+//                      ^
+//              it -----|         => false
+bool CLI2::isEmptyParenExpression (std::vector<A2>::iterator it, bool forward /* = true */) const
+{
+  int open = 0;
+  int closed = 0;
+
+  for (auto a = it; a != (forward ? _args.end (): _args.begin()); (forward ? ++a: --a))
+  {
+    if (a->attribute("raw") == "(")
+      open++;
+    else if (a->attribute("raw") == ")")
+      closed++;
+    else
+      // Encountering a non-paren token means there is something between parenthees
+      return false;
+
+    // Getting balanced parentheses means we have an empty paren expression
+    if (open == closed && open != 0)
+      return true;
+  }
+
+  // Should not end here.
+  return false;
+}
+
+
+////////////////////////////////////////////////////////////////////////////////
 // Two consecutive FILTER, non-OP arguments that are not "(" or ")" need an
 // "and" operator inserted between them.
 //
@@ -1971,10 +2008,18 @@ void CLI2::insertJunctions ()
       // Insert AND between terms.
       else if (a != prev)
       {
-        if ((prev->_lextype != Lexer::Type::op && a->attribute ("raw") == "(")    ||
-            (prev->_lextype != Lexer::Type::op && a->_lextype != Lexer::Type::op) ||
-            (prev->attribute ("raw") == ")"    && a->_lextype != Lexer::Type::op) ||
-            (prev->attribute ("raw") == ")"    && a->attribute ("raw") == "("))
+        if ((prev->_lextype != Lexer::Type::op &&
+             a->attribute ("raw") == "("       &&
+             ! isEmptyParenExpression(a, true)    ) ||
+            (prev->attribute ("raw") == ")"    &&
+             a->_lextype != Lexer::Type::op    &&
+             ! isEmptyParenExpression(prev, false)) ||
+            (prev->attribute ("raw") == ")"    &&
+             a->attribute ("raw") == "("       &&
+             ! isEmptyParenExpression(a, true) &&
+             ! isEmptyParenExpression(prev, false)) ||
+            (prev->_lextype != Lexer::Type::op &&
+             a->_lextype != Lexer::Type::op))
         {
           A2 opOr ("and", Lexer::Type::op);
           opOr.tag ("FILTER");
diff --git a/src/CLI2.h b/src/CLI2.h
index f6b0ce94..025be4c8 100644
--- a/src/CLI2.h
+++ b/src/CLI2.h
@@ -99,6 +99,7 @@ private:
   void findUUIDs ();
   void insertIDExpr ();
   void lexFilterArgs ();
+  bool isEmptyParenExpression (std::vector<A2>::iterator it, bool forward = true) const;
   void desugarFilterPlainArgs ();
   void insertJunctions ();
   void defaultCommand ();
diff --git a/src/columns/ColTypeString.cpp b/src/columns/ColTypeString.cpp
index 37c1433d..4ef97578 100644
--- a/src/columns/ColTypeString.cpp
+++ b/src/columns/ColTypeString.cpp
@@ -58,7 +58,12 @@ void ColumnTypeString::modify (Task& task, const std::string& value)
   std::string domRef;
   Lexer::Type type;
   if (lexer.token (domRef, type) &&
-      type == Lexer::Type::dom)
+      type == Lexer::Type::dom &&
+      // Ensure 'value' contains only the DOM reference and no other tokens
+      // The lexer.token returns false for end-of-string.
+      // This works as long as all the DOM references we should support consist
+      // only of a single token.
+      lexer.token (domRef, type) == false)
   {
     Eval e;
     e.addSource (domSource);