Figure out the issue with indentation of the “first line” in blockstrings

subtle: swift .split omits blank lines by default.
But other issues combined with that.

Author: haikusw

Sources/GraphQL/Language/Lexer.swift

@@ -586,14 +586,7 @@ func readRawString(source: Source, start: Int, line: Int, col: Int, prev: Token)
            body.charCode(at: body.utf8.index(after: positionIndex)) == 34 {
             blockString = true
             positionIndex = body.utf8.index(positionIndex, offsetBy: 2)
-            
-            // if the first character after the """ is a newline, then it is not included in the value
-            if let code = body.charCode(at: positionIndex),
-               (code == 0x000A || code == 0x000D) {
-                positionIndex = body.utf8.index(after: positionIndex)
-            }
-            
-            chunkStartIndex = positionIndex
+			chunkStartIndex = positionIndex
         }
     }
 
@@ -619,7 +612,7 @@ func readRawString(source: Source, start: Int, line: Int, col: Int, prev: Token)
            codeNext == 34,
            let codeNextNext = body.charCode(at: body.utf8.index(after: body.utf8.index(after: positionIndex))),
            codeNextNext == 34 {
-            positionIndex = body.utf8.index(after: body.utf8.index(after: positionIndex))   // so we clean up quotes on exit
+            positionIndex = body.utf8.index(after: body.utf8.index(after: positionIndex))  // position after quotes
             break
         }
 
@@ -749,11 +742,12 @@ func readRawString(source: Source, start: Int, line: Int, col: Int, prev: Token)
  */
 
 func blockStringValue(rawValue: String) -> String {
-    var commonIndent: Int = 0
-    var lines = rawValue.utf8.split { (code) -> Bool in
+    var lines = rawValue.utf8.split(omittingEmptySubsequences: false) { (code) -> Bool in
         return code == 0x000A || code == 0x000D
     }
-    
+
+    var commonIndent: Int = 0
+
     for idx in lines.indices {
         let line = lines[idx]
         if idx == lines.startIndex { continue }
@@ -809,7 +803,7 @@ func blockStringValue(rawValue: String) -> String {
             result.append(contentsOf: Substring(lines[idx]))
         }
     }
-    
+
     return String(result)
 }
 

Tests/GraphQLTests/LanguageTests/LexerTests.swift

@@ -763,7 +763,7 @@ class LexerTests : XCTestCase {
                              end: 66,
                              line: 1,
                              column: 1,
-                             value: "    TopLevel {\n        indented\n        alsoIndented\n    }\n",
+                             value: "\n    TopLevel {\n        indented\n        alsoIndented\n    }\n",
                              prev: nil, next: nil)
 
         let source = Source(body: sourceStr, name: "TestSource")
@@ -777,25 +777,43 @@ class LexerTests : XCTestCase {
     }
 
     func testBlockStringIndentationAndBlankLine() throws {
-        let rawString = "\n\n\n    TopLevel {\n        indented\n        alsoIndented\n    }\n\n\n\t\t\n"   // from testReadRawString() above
+        let rawString = "\n\n\n    TopLevel {\n        indented\n        alsoIndented\n    }\n\n\n\t\t\n"
         let cleanedString = blockStringValue(rawValue: rawString)
 
-        XCTAssertEqual(cleanedString, "    TopLevel {\n    indented\n    alsoIndented\n}")
+        XCTAssertEqual(cleanedString, "TopLevel {\n    indented\n    alsoIndented\n}")
     }
 
     func testBlockStringDoubleIndentationAndBlankLine() throws {
-        let rawString = "\n\n\n    TopLevel {\n        indented: {\n            foo: String\n        }\n        alsoIndented\n    }\n\n\n\t\t\n"   // from testReadRawString() above
+        let rawString = "\n\n\n    TopLevel {\n        indented: {\n            foo: String\n        }\n        alsoIndented\n    }\n\n\n\t\t\n"
         let cleanedString = blockStringValue(rawValue: rawString)
 
-        XCTAssertEqual(cleanedString, "    TopLevel {\n    indented: {\n        foo: String\n    }\n    alsoIndented\n}")
+        XCTAssertEqual(cleanedString, "TopLevel {\n    indented: {\n        foo: String\n    }\n    alsoIndented\n}")
     }
 
     func testBlockStringIndentationAndBlankLineFirstLineNotIndentedWeird() throws {
-        let rawString = "\n\n\nTopLevel {\n        indented\n        alsoIndented\n    }\n\n\n\t\t\n"   // from testReadRawString() above
+        let rawString = "\n\n\nTopLevel {\n        indented\n        alsoIndented\n}\n\n\n\t\t\n"
+        let cleanedString = blockStringValue(rawValue: rawString)
+        
+        XCTAssertEqual(cleanedString, "TopLevel {\n        indented\n        alsoIndented\n}")
+    }
+
+    func testBlockStringIndentationMultilineAndBlankLineFirstLineNotIndentedWeird() throws {
+        let rawString = """
+            
+            
+            TopLevel {
+                indented
+                alsoIndented
+            }
+            
+            
+            \t
+            """
         let cleanedString = blockStringValue(rawValue: rawString)
 
         XCTAssertEqual(cleanedString, "TopLevel {\n    indented\n    alsoIndented\n}")
     }
+
 
     // Lexer tests for multi-line string token parsing
 
@@ -869,6 +887,34 @@ class LexerTests : XCTestCase {
 
         XCTAssertEqual(token, expected, "expected: \n \(dump(expected))\ngot: \n\(dump(token))\n")
     }
+    
+    func testMultilineStrings_stringIndentedInStream() throws {
+        let sourceStr =
+            #"""
+                """
+                Multi-line string {
+                    with Inner "foo"
+                    should be valid indented
+                }
+                """
+            """#
+        
+        let token = try lexOne(sourceStr)
+        
+        let expected = Token(
+            kind: .string,
+            start: 4,
+            end: 103,
+            line: 1,
+            column: 5,
+            value: "Multi-line string {\n    with Inner \"foo\"\n    should be valid indented\n}"
+        )
+        
+        print(sourceStr)
+        
+        XCTAssertEqual(token, expected, "expected: \n \(dump(expected))\ngot: \n\(dump(token))\n")
+    }
+
 
     // Test empty strings & multi-line string lexer token parsing