feature #26449 Make ProgressBar::setMaxSteps public (ostrolucky)

This PR was merged into the 4.1-dev branch.

Discussion
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Make ProgressBar::setMaxSteps public

| Q             | A
| ------------- | ---
| Branch?       | master
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #24100
| License       | MIT
| Doc PR        | -

This is useful in cases when target of tracking changes its size during progress advancement. My exact use case is showing progress of file upload for file which is still being downloading.

Commits
-------

2b3c37a Make ProgressBar::setMaxSteps public

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

@@ -295,6 +295,13 @@ public function setProgress(int $step)
         }
     }
 
+    public function setMaxSteps(int $max)
+    {
+        $this->format = null;
+        $this->max = max(0, $max);
+        $this->stepWidth = $this->max ? Helper::strlen((string) $this->max) : 4;
+    }
+
     /**
      * Finishes the progress output.
      */
@@ -362,12 +369,6 @@ private function setRealFormat(string $format)
         $this->formatLineCount = substr_count($this->format, "\n");
     }
 
-    private function setMaxSteps(int $max)
-    {
-        $this->max = max(0, $max);
-        $this->stepWidth = $this->max ? Helper::strlen((string) $this->max) : 4;
-    }
-
     /**
      * Overwrites a previous message to the output.
      */

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

@@ -592,6 +592,29 @@ public function testWithoutMax()
         );
     }
 
+    public function testSettingMaxStepsDuringProgressing()
+    {
+        $output = $this->getOutputStream();
+        $bar = new ProgressBar($output);
+        $bar->start();
+        $bar->setProgress(2);
+        $bar->setMaxSteps(10);
+        $bar->setProgress(5);
+        $bar->setMaxSteps(100);
+        $bar->setProgress(10);
+        $bar->finish();
+
+        rewind($output->getStream());
+        $this->assertEquals(
+            rtrim('    0 [>---------------------------]').
+            rtrim($this->generateOutput('    2 [-->-------------------------]')).
+            rtrim($this->generateOutput('  5/10 [==============>-------------]  50%')).
+            rtrim($this->generateOutput('  10/100 [==>-------------------------]  10%')).
+            rtrim($this->generateOutput(' 100/100 [============================] 100%')),
+            stream_get_contents($output->getStream())
+        );
+    }
+
     public function testWithSmallScreen()
     {
         $output = $this->getOutputStream();