Csv reader avoid notice when the file is empty

Fixes #337

Author: Laurent

CHANGELOG.md

@@ -11,6 +11,7 @@ and this project adheres to [Semantic Versioning](https://semver.org).
 
 - Support numeric condition in SUMIF, SUMIFS, AVERAGEIF, COUNTIF, MAXIF and MINIF - [#683](https://github.com/PHPOffice/PhpSpreadsheet/issues/683)
 - SUMIFS containing multiple conditions - [#704](https://github.com/PHPOffice/PhpSpreadsheet/issues/704)
+- Csv reader avoid notice when the file is empty - [#743](https://github.com/PHPOffice/PhpSpreadsheet/pull/743)
 
 ## [1.5.0] - 2018-10-21
 

src/PhpSpreadsheet/Reader/Csv.php

@@ -181,6 +181,13 @@ protected function inferSeparator()
             }
         }
 
+        // If number of lines is 0, nothing to infer : fall back to the default
+        if ($numberLines === 0) {
+            $this->delimiter = reset($potentialDelimiters);
+
+            return $this->skipBOM();
+        }
+
         // Calculate the mean square deviations for each delimiter (ignoring delimiters that haven't been found consistently)
         $meanSquareDeviations = [];
         $middleIdx = floor(($numberLines - 1) / 2);

tests/PhpSpreadsheetTests/Reader/CsvTest.php

@@ -67,6 +67,18 @@ public function providerDelimiterDetection()
                 'D8',
                 -58.373161,
             ],
+            [
+                'data/Reader/CSV/empty.csv',
+                ',',
+                'A1',
+                null,
+            ],
+            [
+                'data/Reader/CSV/no_delimiter.csv',
+                ',',
+                'A1',
+                'SingleLine',
+            ],
         ];
     }
 

tests/data/Reader/CSV/no_delimiter.csv

@@ -0,0 +1 @@
+SingleLine