Fix #6538: Make interfaces.SourcePosition resilient to missing sources

compiler/src/dotty/tools/dotc/util/SourcePosition.scala

@@ -22,8 +22,7 @@ extends interfaces.SourcePosition with Showable {
 
   def point: Int = span.point
 
-  /** The line of the position, starting at 0 */
-  def line: Int = source.offsetToLine(point)
+  def line: Int = if (source.exists) source.offsetToLine(point) else -1
 
   /** Extracts the lines from the underlying source file as `Array[Char]`*/
   def linesSlice: Array[Char] =
@@ -43,17 +42,16 @@ extends interfaces.SourcePosition with Showable {
   def beforeAndAfterPoint: (List[Int], List[Int]) =
     lineOffsets.partition(_ <= point)
 
-  /** The column of the position, starting at 0 */
-  def column: Int = source.column(point)
+  def column: Int = if (source.exists) source.column(point) else -1
 
   def start: Int = span.start
-  def startLine: Int = source.offsetToLine(start)
-  def startColumn: Int = source.column(start)
+  def startLine: Int = if (source.exists) source.offsetToLine(start) else -1
+  def startColumn: Int = if (source.exists) source.column(start) else -1
   def startColumnPadding: String = source.startColumnPadding(start)
 
   def end: Int = span.end
-  def endLine: Int = source.offsetToLine(end)
-  def endColumn: Int = source.column(end)
+  def endLine: Int = if (source.exists) source.offsetToLine(end) else -1
+  def endColumn: Int = if (source.exists) source.column(end) else -1
 
   def withOuter(outer: SourcePosition): SourcePosition = SourcePosition(source, span, outer)
   def withSpan(range: Span) = SourcePosition(source, range, outer)

interfaces/src/dotty/tools/dotc/interfaces/SourcePosition.java

@@ -17,23 +17,23 @@ public interface SourcePosition {
 
   /** @return Offset to the point */
   int point();
-  /** @return Line number of the point, starting at 0 */
+  /** @return Line number of the point, starting at 0. -1 if the line cannot be computed */
   int line();
-  /** @return Column number of the point, starting at 0 */
+  /** @return Column number of the point, starting at 0. -1 if the column cannot be computed */
   int column();
 
   /** @return Offset to the range start */
   int start();
-  /** @return Line number of the range start, starting at 0 */
+  /** @return Line number of the range start, starting at 0. -1 if the line cannot be computed */
   int startLine();
-  /** @return Column number of the range start, starting at 0 */
+  /** @return Column number of the range start, starting at 0. -1 if the column cannot be computed */
   int startColumn();
 
   /** @return Offset to the range end */
   int end();
-  /** @return Line number of the range end, starting at 0 */
+  /** @return Line number of the range end, starting at 0. -1 if the line cannot be computed */
   int endLine();
-  /** @return Column number of the range end, starting at 0 */
+  /** @return Column number of the range end, starting at 0. -1 if the column cannot be computed */
   int endColumn();
 
   /** The source file corresponding to this position.

sbt-bridge/src/xsbt/DelegatingReporter.java

@@ -80,13 +80,17 @@ public void doReport(MessageContainer cont, Context ctx) {
       SourceFile src = pos.source();
       position = new Position() {
         public Optional<java.io.File> sourceFile() {
-          return Optional.ofNullable(src.file().file());
+          if (src.exists()) return Optional.empty();
+          else return Optional.ofNullable(src.file().file());
         }
         public Optional<String> sourcePath() {
-          return Optional.ofNullable(src.file().path());
+          if (src.exists()) return Optional.empty();
+          else return Optional.ofNullable(src.file().path());
         }
         public Optional<Integer> line() {
-          return Optional.of(pos.line());
+          int line = pos.line();
+          if (line == -1) return Optional.empty();
+          else return Optional.of(line);
         }
         public String lineContent() {
           String line = pos.lineContent();
@@ -101,15 +105,19 @@ public Optional<Integer> offset() {
           return Optional.of(pos.point());
         }
         public Optional<Integer> pointer() {
-          return Optional.of(pos.point() - src.startOfLine(pos.point()));
+          if (!src.exists()) return Optional.empty();
+          else return Optional.of(pos.point() - src.startOfLine(pos.point()));
         }
         public Optional<String> pointerSpace() {
-          String lineContent = this.lineContent();
-          int pointer = this.pointer().get();
-          StringBuilder result = new StringBuilder();
-          for (int i = 0; i < pointer; i++)
-            result.append(lineContent.charAt(i) == '\t' ? '\t' : ' ');
-          return Optional.of(result.toString());
+          if (!src.exists()) return Optional.empty();
+          else {
+            String lineContent = this.lineContent();
+            int pointer = this.pointer().get();
+            StringBuilder result = new StringBuilder();
+            for (int i = 0; i < pointer; i++)
+              result.append(lineContent.charAt(i) == '\t' ? '\t' : ' ');
+            return Optional.of(result.toString());
+          }
         }
       };
     } else {