1461885 - File input content null if file size changed after selection

Status: RESOLVED DUPLICATE of bug 660148

(Core :: DOM: File, defect, P3)

Description

[Mike Hodgson]

Attachment: Testcase for File input content null if file size changed after selection

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:60.0) Gecko/20100101 Firefox/60.0
Build ID: 20180503143129

Steps to reproduce:

1. Create a test text file with a known file size, such as a text file containing "qwerty".

2. In the attached test case, select the text file for the file input, and then click Read File to read the contents.

3. Modify the text file contents, save the text file, and then click Read File again.


Actual results:

If the modified text file contents are the same length, the file is successfully re-read.
For example: "asdfgh"

Size: 6 bytes
Content: asdfgh

If the text file content is a different length, the content cannot be read.
For example:  "qwert" or "qwertyu"

Size: 6 bytes
Content: null

I noted that after the failed read, returning the file to the same content length, regardless of what the content is, the file may be read again.


Expected results:

When performing this test in Chrome, the file is re-read successfully when the content length has changed. For example the output will display for "qwert" and "qwertyu" as follows:

Size: 5 bytes
Content: qwert

Size: 7 bytes
Content: qwertyu

Comment 1

[Gingerbread Man]

Also see bug 660148 and bug 1264371.

Comment 2

[Jens Stutte [:jstutte]]

The testcase still reproduces. We need to check in bug 660148 how the spec evolved here.