bug symfony#18496 [Console] use ANSI escape sequences in ProgressBar overwrite method (alekitto)

This PR was squashed before being merged into the 2.7 branch (closes symfony#18496).

Discussion
----------

[Console] use ANSI escape sequences in ProgressBar overwrite method

| Q             | A
| ------------- | ---
| Branch?       | 2.7
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | maybe
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | symfony#16957
| License       | MIT
| Doc PR        |

Rewritten `overwrite` method in ProgressBar class to use ANSI escape sequences to erase lines.
This removes the need to store the last message length as it is not needed to fill the buffer with spaces anymore. As a plus it correctly resets the cursor position while clearing the output

If the output is not decorated the behavior has not been changed.
Could possibly cause a BC break if testing against the decorated emitted output as binary string

Commits
-------

b6cca4c [Console] use ANSI escape sequences in ProgressBar overwrite method

Author: fabpot

src/Symfony/Component/Console/Helper/ProgressBar.php

@@ -40,7 +40,6 @@ class ProgressBar
     private $startTime;
     private $stepWidth;
     private $percent = 0.0;
-    private $lastMessagesLength = 0;
     private $formatLineCount;
     private $messages;
     private $overwrite = true;
@@ -472,7 +471,7 @@ public function clear()
             $this->setRealFormat($this->internalFormat ?: $this->determineBestFormat());
         }
 
-        $this->overwrite(str_repeat("\n", $this->formatLineCount));
+        $this->overwrite('');
     }
 
     /**
@@ -512,37 +511,22 @@ private function setMaxSteps($max)
      */
     private function overwrite($message)
     {
-        $lines = explode("\n", $message);
-
-        // append whitespace to match the line's length
-        if (null !== $this->lastMessagesLength) {
-            foreach ($lines as $i => $line) {
-                if ($this->lastMessagesLength > Helper::strlenWithoutDecoration($this->output->getFormatter(), $line)) {
-                    $lines[$i] = str_pad($line, $this->lastMessagesLength, "\x20", STR_PAD_RIGHT);
-                }
-            }
-        }
-
         if ($this->overwrite) {
-            // move back to the beginning of the progress bar before redrawing it
+            // Move the cursor to the beginning of the line
             $this->output->write("\x0D");
-        } elseif ($this->step > 0) {
-            // move to new line
-            $this->output->writeln('');
-        }
 
-        if ($this->formatLineCount) {
-            $this->output->write(sprintf("\033[%dA", $this->formatLineCount));
-        }
-        $this->output->write(implode("\n", $lines));
+            // Erase the line
+            $this->output->write("\x1B[2K");
 
-        $this->lastMessagesLength = 0;
-        foreach ($lines as $line) {
-            $len = Helper::strlenWithoutDecoration($this->output->getFormatter(), $line);
-            if ($len > $this->lastMessagesLength) {
-                $this->lastMessagesLength = $len;
+            // Erase previous lines
+            if ($this->formatLineCount > 0) {
+                $this->output->write(str_repeat("\x1B[1A\x1B[2K", $this->formatLineCount));
             }
+        } elseif ($this->step > 0) {
+            $this->output->writeln('');
         }
+
+        $this->output->write($message);
     }
 
     private function determineBestFormat()

src/Symfony/Component/Console/Tests/Helper/ProgressBarTest.php

@@ -233,7 +233,7 @@ public function testOverwriteWithShorterLine()
             $this->generateOutput('  0/50 [>---------------------------]   0%').
             $this->generateOutput('  0/50 [>---------------------------]   0%').
             $this->generateOutput('  1/50 [>---------------------------]   2%').
-            $this->generateOutput('  2/50 [=>--------------------------]     '),
+            $this->generateOutput('  2/50 [=>--------------------------]'),
             stream_get_contents($output->getStream())
         );
     }
@@ -356,7 +356,7 @@ public function testClear()
         $this->assertEquals(
             $this->generateOutput('  0/50 [>---------------------------]   0%').
             $this->generateOutput(' 25/50 [==============>-------------]  50%').
-            $this->generateOutput('                                          '),
+            $this->generateOutput(''),
             stream_get_contents($output->getStream())
         );
     }
@@ -554,9 +554,9 @@ public function testMultilineFormat()
         rewind($output->getStream());
         $this->assertEquals(
             $this->generateOutput(">---------------------------\nfoobar").
-            $this->generateOutput("=========>------------------\nfoobar                      ").
-            $this->generateOutput("                            \n                            ").
-            $this->generateOutput("============================\nfoobar                      "),
+            $this->generateOutput("=========>------------------\nfoobar").
+            "\x0D\x1B[2K\x1B[1A\x1B[2K".
+            $this->generateOutput("============================\nfoobar"),
             stream_get_contents($output->getStream())
         );
     }
@@ -665,6 +665,6 @@ protected function generateOutput($expected)
     {
         $count = substr_count($expected, "\n");
 
-        return "\x0D".($count ? sprintf("\033[%dA", $count) : '').$expected;
+        return "\x0D\x1B[2K".($count ? str_repeat("\x1B[1A\x1B[2K", $count) : '').$expected;
     }
 }