Copying text into first paragraph causes blank Paragraph Block to appear above text

[maddisondesigns]

Describe the bug
I created a new page and pasted some (unformatted) text content into the first Paragraph block after the title. Instead of actually pasting the text into the Paragraph Block though, it created a whole new Paragraph Block and pasted the text into that instead, leaving me with a blank Paragraph Block.

To Reproduce
Steps to reproduce the behavior:

1. Copy some unformatted text from somewhere
2. Create new Page
3. Type Page title in Title Block
4. Put cursor in first Paragraph Block
5. Hit Ctrl-V/Cmd+V to Paste text
6. A new Paragrph Block is created and the text appears in this block instead of the Block where you tried to paste it

Expected behavior
When I paste plain text into a Paragraph Block, it should paste into the Block where my cursor is, not create a brand new Block, leaving me with an empty Block.

macOS Sierra 10.12.6 (16G1510)
Firefox Quantum 61.0.1 (64-bit)
Gutenberg 3.2.0

[ZebulanStanphill]

I have confirmed this is happening in master right now.

[designsimply]

Tested and confirmed that an empty paragraph block remains after I copy text from elsewhere that contains leading line breaks. I found that I was able to copy some text over without that happening if I only select a portion of text that does not include the beginning of a line.

Video: 1m21s
^{Seen at http://alittletestblog.com/wp-admin/post.php?post=13996&action=edit running WordPress 4.9.7 and Gutenberg 3.2.0 using Firefox 61.0.1 on macOS 10.13.5.}

[ghost]

I copied text from pdf but when I switched to the classic editor, there were double spacing (&npsb;) after each paragraph. This is awful for a document of 1500 words.

[designsimply]

@matto15 in your case it sounds like whatever was used to create the pdf had some special formatting to hide double spacing ( ), and if the underlying code had empty paragraphs included as double spacing, it makes sense for an editor to honor that. I would be interested to learn more about what was used to create that pdf (if you know) or to look at it directly (if it can be shared), and if you're interested in talking about it more too, please add a new post at https://wordpress.org/support/plugin/gutenberg/

[designsimply]

Closing this so we can consolidate in #7616 which addresses the underlying problem here which is that when you paste content with leading white space, such as a line break, it results in an empty block that shouldn't be there.