Handle files disappearing during analysis (#3390)

packages/flutter_tools/lib/src/commands/analyze.dart

@@ -363,53 +363,52 @@ class AnalyzeCommand extends FlutterCommand {
           String errorMessage = groups[2];
           int lineNumber = int.parse(groups[4]);
           int colNumber = int.parse(groups[5]);
-          File source = new File(filename);
-          List<String> sourceLines = source.readAsLinesSync();
-          String sourceLine;
           try {
+            File source = new File(filename);
+            List<String> sourceLines = source.readAsLinesSync();
             if (lineNumber > sourceLines.length)
               throw new FileChanged();
-            sourceLine = sourceLines[lineNumber-1];
+            String sourceLine = sourceLines[lineNumber-1];
             if (colNumber > sourceLine.length)
               throw new FileChanged();
-          } on FileChanged {
-            if (changedFiles.add(filename))
-              printError('[warning] File shrank during analysis ($filename)');
-            sourceLine = '';
-            lineNumber = 1;
-            colNumber = 1;
-          }
-          bool shouldIgnore = false;
-          if (documentAllMembersPattern.firstMatch(errorMessage) != null) {
-            // https://github.com/dart-lang/linter/issues/207
-            // https://github.com/dart-lang/linter/issues/208
-            if (isFlutterLibrary(filename)) {
-              if (!argResults['dartdocs']) {
-                membersMissingDocumentation += 1;
+            bool shouldIgnore = false;
+            if (documentAllMembersPattern.firstMatch(errorMessage) != null) {
+              // https://github.com/dart-lang/linter/issues/207
+              // https://github.com/dart-lang/linter/issues/208
+              if (isFlutterLibrary(filename)) {
+                if (!argResults['dartdocs']) {
+                  membersMissingDocumentation += 1;
+                  shouldIgnore = true;
+                }
+              } else {
                 shouldIgnore = true;
               }
-            } else {
+            } else if (filename == mainFile.path) {
+              Match libs = conflictingNamesPattern.firstMatch(errorMessage);
+              Match missing = missingFilePattern.firstMatch(errorMessage);
+              if (libs != null) {
+                errorLine = '[$level] $errorMessage (${dartFiles[lineNumber-1]})'; // strip the reference to the generated main.dart
+              } else if (missing != null) {
+                errorLine = '[$level] File does not exist (${missing[1]})';
+              } else {
+                errorLine += ' (Please file a bug on the "flutter analyze" command saying that you saw this message.)';
+              }
+            } else if (filename.endsWith('.mojom.dart')) {
+              // autogenerated code - TODO(ianh): Fix the Dart mojom compiler
+              shouldIgnore = true;
+            } else if (sourceLines.first.startsWith('// DO NOT EDIT. This is code generated')) {
+              // autogenerated code - TODO(ianh): Fix the intl package resource generator
               shouldIgnore = true;
             }
-          } else if (filename == mainFile.path) {
-            Match libs = conflictingNamesPattern.firstMatch(errorMessage);
-            Match missing = missingFilePattern.firstMatch(errorMessage);
-            if (libs != null) {
-              errorLine = '[$level] $errorMessage (${dartFiles[lineNumber-1]})'; // strip the reference to the generated main.dart
-            } else if (missing != null) {
-              errorLine = '[$level] File does not exist (${missing[1]})';
-            } else {
-              errorLine += ' (Please file a bug on the "flutter analyze" command saying that you saw this message.)';
-            }
-          } else if (filename.endsWith('.mojom.dart')) {
-            // autogenerated code - TODO(ianh): Fix the Dart mojom compiler
-            shouldIgnore = true;
-          } else if (sourceLines.first.startsWith('// DO NOT EDIT. This is code generated')) {
-            // autogenerated code - TODO(ianh): Fix the intl package resource generator
-            shouldIgnore = true;
+            if (shouldIgnore)
+              continue;
+          } on FileSystemException catch (exception) {
+            if (changedFiles.add(filename))
+              printError('[warning] Could not read file (${exception.message}${ exception.osError != null ? "; ${exception.osError}" : ""}) ($filename)');
+          } on FileChanged {
+            if (changedFiles.add(filename))
+              printError('[warning] File shrank during analysis ($filename)');
           }
-          if (shouldIgnore)
-            continue;
         }
         printError(errorLine);
         errorCount += 1;