fix range building for tabs or mixed tabs/spaces files

build.sbt

@@ -230,16 +230,19 @@ lazy val minimized = project
   .in(file("tests/minimized/.j11"))
   .settings(minimizedSettings)
   .dependsOn(agent, plugin)
+  .disablePlugins(JavaFormatterPlugin)
 
 lazy val minimized8 = project
   .in(file("tests/minimized/.j8"))
   .settings(minimizedSettings, javaToolchainVersion := "8")
   .dependsOn(agent, plugin)
+  .disablePlugins(JavaFormatterPlugin)
 
 lazy val minimized15 = project
   .in(file("tests/minimized/.j15"))
   .settings(minimizedSettings, javaToolchainVersion := "15")
   .dependsOn(agent, plugin)
+  .disablePlugins(JavaFormatterPlugin)
 
 lazy val minimizedScala = project
   .in(file("tests/minimized-scala"))

semanticdb-javac/src/main/java/com/sourcegraph/semanticdb_javac/SemanticdbVisitor.java

@@ -255,6 +255,7 @@ private String semanticdbSymbol(Symbol sym) {
 
   private Optional<Semanticdb.Range> semanticdbRange(
       JCDiagnostic.DiagnosticPosition pos, CompilerRange kind, Symbol sym) {
+    LineMap lineMap = event.getCompilationUnit().getLineMap();
     if (sym == null) return Optional.empty();
     int start, end;
     if (kind.isFromPoint() && sym.name != null) {
@@ -269,21 +270,53 @@ private Optional<Semanticdb.Range> semanticdbRange(
     }
 
     if (kind.isFromTextSearch() && sym.name.length() > 0) {
-      return RangeFinder.findRange(
-          getCurrentPath(), trees, getCurrentPath().getCompilationUnit(), sym, start, this.source);
+      Optional<Semanticdb.Range> range =
+          RangeFinder.findRange(
+              getCurrentPath(),
+              trees,
+              getCurrentPath().getCompilationUnit(),
+              sym,
+              start,
+              this.source);
+      if (range.isPresent()) return Optional.of(correctForTabs(range.get(), lineMap, start));
+      else return range;
     } else if (start != Position.NOPOS && end != Position.NOPOS && end > start) {
-      LineMap lineMap = event.getCompilationUnit().getLineMap();
       Semanticdb.Range range =
           Semanticdb.Range.newBuilder()
               .setStartLine((int) lineMap.getLineNumber(start) - 1)
               .setStartCharacter((int) lineMap.getColumnNumber(start) - 1)
               .setEndLine((int) lineMap.getLineNumber(end) - 1)
               .setEndCharacter((int) lineMap.getColumnNumber(end) - 1)
               .build();
+
+      range = correctForTabs(range, lineMap, start);
+
       return Optional.of(range);
-    } else {
-      return Optional.empty();
     }
+
+    return Optional.empty();
+  }
+
+  private Semanticdb.Range correctForTabs(Semanticdb.Range range, LineMap lineMap, int start) {
+    int startLinePos = (int) lineMap.getPosition(lineMap.getLineNumber(start), 0);
+
+    // javac replaces every tab with 8 spaces in the linemap. As this is potentially inconsistent
+    // with the source file itself, we adjust for that here if the line is actually indented with
+    // tabs.
+    // As for every tab there are 8 spaces, we remove 7 spaces for every tab to get the correct
+    // char offset (note: different to _column_ offset your editor shows)
+    if (this.source.charAt(startLinePos) == '\t') {
+      int count = 1;
+      while (this.source.charAt(++startLinePos) == '\t') count++;
+      range =
+          range
+              .toBuilder()
+              .setStartCharacter(range.getStartCharacter() - (count * 7))
+              .setEndCharacter(range.getEndCharacter() - (count * 7))
+              .build();
+    }
+
+    return range;
   }
 
   private Optional<Semanticdb.SymbolOccurrence> semanticdbOccurrence(

tests/minimized/src/main/java/minimized/TabIndented.java

@@ -0,0 +1,17 @@
+package minimized;
+
+public class TabIndented {
+	public void app() {
+		Object o = new Object() {
+			@Override
+			public boolean equals(Object other) {
+				return false;
+			}
+
+			@Override
+			public String toString() {
+				return "";
+			}
+		};
+	}
+}

tests/snapshots/src/main/generated/minimized/TabIndented.java

@@ -0,0 +1,30 @@
+package minimized;
+
+public class TabIndented {
+//           ^^^^^^^^^^^ definition minimized/TabIndented# public class TabIndented
+//           ^^^^^^^^^^^ definition minimized/TabIndented#`<init>`(). public TabIndented()
+→public void app() {
+//           ^^^ definition minimized/TabIndented#app(). public void app()
+→→Object o = new Object() {
+//^^^^^^ reference java/lang/Object#
+//       ^ definition local0 Object o
+//               ^^^^^^ reference java/lang/Object#
+→→→@Override
+//  ^^^^^^^^ reference java/lang/Override#
+→→→public boolean equals(Object other) {
+//                ^^^^^^ definition local3 @Override public boolean equals(Object other)
+//                       ^^^^^^ reference java/lang/Object#
+//                              ^^^^^ definition local5 Object other
+→→→→return false;
+→→→}
+
+→→→@Override
+//  ^^^^^^^^ reference java/lang/Override#
+→→→public String toString() {
+//        ^^^^^^ reference java/lang/String#
+//               ^^^^^^^^ definition local4 @Override public String toString()
+→→→→return "";
+→→→}
+→→};
+→}
+}