svn status does not detect a modification if the same file was touched

[Sasikala Kottegoda]

Hi all,

I'm using svn version 1.9.3 and I have come across the following:

- A file named a.txt exists inside a folder in the working copy, which
has been copied from somewhere else
- cCopy and replace a.txt with the same file/or modify it by issuing the
'touch' command
- Do an svn status, it shows nothing
- Do an svn info on the file and 'Last Changed Date' shows the same as
the previous file. It does not get modified even though the file was newly
copied.
- But the from java files API, the file is shown with a different
modified date

Why do we not modify the 'Last Changed Date' when the file was newly
copied/touched?

Thank you,
Sasikala

[Andreas Stieger]

Greetings,

Post by Sasikala Kottegoda
A file named a.txt exists inside a folder in the working copy, which
has been copied from somewhere else
* cCopy and replace a.txt with the same file/or modify it by issuing
the 'touch' command
* Do an svn status, it shows nothing
* Do an svn info on the file and 'Last Changed Date' shows the same
as the previous file. It does not get modified even though the
file was newly copied.
* But the from java files API, the file is shown with a different
modified date
Why do we not modify the 'Last Changed Date' when the file was newly
copied/touched?

Last Changed Date refers to the last change of the version item in the
repository that the working copy knows about. It does not relate or
account for local file system changes, neither in identity (inode),
timestamps (touch) nor content - because this is a local change that
does not change the versioned item until commit.

Andreas

[Sasikala Kottegoda]

Hi Andreas,

Thanks for the prompt reply.

In this scenario, svn status does not show anything. Also, the file does
not get commited when I issue an 'svn commit'. Is there a reason for that?

Thank you,
Sasikala

Post by Andreas Stieger
Greetings,

Post by Sasikala Kottegoda
A file named a.txt exists inside a folder in the working copy, which
has been copied from somewhere else
* cCopy and replace a.txt with the same file/or modify it by issuing
the 'touch' command
* Do an svn status, it shows nothing
* Do an svn info on the file and 'Last Changed Date' shows the same
as the previous file. It does not get modified even though the
file was newly copied.
* But the from java files API, the file is shown with a different
modified date
Why do we not modify the 'Last Changed Date' when the file was newly
copied/touched?

Last Changed Date refers to the last change of the version item in the
repository that the working copy knows about. It does not relate or
account for local file system changes, neither in identity (inode),
timestamps (touch) nor content - because this is a local change that
does not change the versioned item until commit.
Andreas

[Ralph Seichter]

Post by Sasikala Kottegoda
In this scenario, svn status does not show anything. Also, the file
does not get commited when I issue an 'svn commit'. Is there a reason
for that?

Subversion uses a hash of the file content to determine if it has been
modified. Changing the modification date in the working copy, as you did
with 'touch', does not alter the content, hence the file is considered
unchanged. This is deliberate.

-Ralph

[Daniel Shahaf]

Post by Ralph Seichter

Post by Sasikala Kottegoda
In this scenario, svn status does not show anything. Also, the file
does not get commited when I issue an 'svn commit'. Is there a reason
for that?

Subversion uses a hash of the file content to determine if it has been
modified. Changing the modification date in the working copy, as you did
with 'touch', does not alter the content, hence the file is considered
unchanged.

Subversion doesn't use checksums to detect modifications. 'svn status'
is based on filesize + mtime only. If mtime differs but filesize doesn't, then
a full content diff is done.

Post by Ralph Seichter
This is deliberate.

Yes, it is, for efficiency reasons. (stat() is cheaper than read())

[Ralph Seichter]

Subversion doesn't use checksums to detect modifications. 'svn status'
is based on filesize + mtime only.

I seemed to remember subversion behaved like git in this regard, using a
checksum (as shown in 'svn info') as an indicator, rather than raw file
size. Oh well, I'm pretty sure you know first-hand how it works. ;-)

-Ralph

[Daniel Shahaf]

Post by Ralph Seichter

Subversion doesn't use checksums to detect modifications. 'svn status'
is based on filesize + mtime only.

I seemed to remember subversion behaved like git in this regard, using a
checksum (as shown in 'svn info') as an indicator, rather than raw file
size. Oh well, I'm pretty sure you know first-hand how it works. ;-)

https://svn.apache.org/viewvc/subversion/trunk/subversion/libsvn_wc/questions.c?revision=1801448&view=markup#l258

:-)