How to make `hg diff` show whitespace changes?

[Noemi Millman]

`hg update -C` does not clear the changes.  Only nuking the resource forks seems to.


> On Jan 14, 2016, at 11:04 AM, Matt Harbison <mharbison72 at gmail.com> wrote:
> 
> (cc: list)
> 
> On Thu, 14 Jan 2016 10:26:05 -0500, Noemi Millman <noemi.millman at backstage.com> wrote:
> 
>> 
>> Thanks, Matt!
>> 
>> Great call about the resource forks (and a facepalm moment for me!)  I can confirm that that's the problem, since changing the default app to open a file without editing the file itself adds it to the list of mysteriously changed-yet-unchanged files.
>> 
>> I wonder why Mercurial recognizes resource fork changes but git doesn't?
> 
> It's been a few months since I looked into it, but IIRC, the python call used to determine the file size sees both the data and resource forks.  Thats going to be different from the data-fork-only size in Mercurial.  So nothing you can do without submitting patches, but you should probably wait until after Feb 1 to do that.  It may be too close to a code freeze now to mess around with that.
> 
> I noticed it because of beyondcompare like I said, but it was "intermittent" because extdiff sometimes copies the files to a temp directory, and sometimes opens them in place.  When Mercurial copies the file back to your working directory from /tmp, it ignores the resource fork that was made in /tmp/foo, so the problem doesn't happen.
> 
> If you can't restore to a clean copy with 'update -C', that seems like a bug to me.
> 
>> I'll have to do a bit of research to figure out how to get Mercurial to ignore them, and will post back if I can for the reference of anyone who encounters this in the future.
>> 
>> cheers,
>> -Noemi
>> 
>>> On Jan 13, 2016, at 10:58 PM, Matt Harbison <mharbison72 at gmail.com> wrote:
>>> 
>>> On Wed, 13 Jan 2016 11:03:37 -0500, Noemi Millman <noemi.millman at backstage.com> wrote:
>>> 
>>>> Thanks, Matt!
>>>> 
>>>> Why would a merge show a file as changed if contents, permissions, line endings, etc. haven't changed?
>>> 
>>> In addition to what Matt said (which is likely the reason for your merge issue), be aware of resource forks on OS X.  Mercurial doesn't track or handle them, but if a tool adds one, status will say 'M' and diff will show nothing because the file size changes.  You can see if you have them with `ls -l@`.
>>> 
>>> They seem to get created with BeyondCompare on 10.6.8, but not on 10.10.  I forget if `hg update -C` removes them, but I'm thinking not since I've gotten into the habit of manually removing them.
>>> 
>>>>> On Jan 13, 2016, at 10:53 AM, Matt Mackall <mpm at selenic.com> wrote:
>>>>> 
>>>>> On Wed, 2016-01-13 at 07:13 -0800, Noemi wrote:
>>>>>> When I run `hg status`, it shows a few files as changed, but `hg diff`
>>>>>> outputs absolutely nothing.  Why might this happen other than whitespace
>>>>>> changes?
>>>>> 
>>>>> Line ending, empty vs deleted, copies, renames, exec bits, merges, etc.
>>>>> 
>>>>>> If it is whitespace changes, how can I make `hg diff` display
>>>>>> them?  The docs explain how to ignore whitespace changes, but not how to
>>>>>> make sure they're displayed.
>>>>> 
>>>>> They're displayed by default.
>>>>> 
>>>>> The standard diff tool was created in 1974. Mercurial was created in 2005. So
>>>>> asking why the diff format doesn't capture all the details is a bit like asking
>>>>> why a VHS (1976) copy of a BluRay (2006) doesn't look as good.
>>>>> 
>>>>> We also support the Git format with -g which will show some but not all of the
>>>>> aforementioned differences and also breaks some of the tools that work with
>>>>> standard diffs.
>>>>> 
>>>>> --
>>>>> Mathematics is the supreme nostalgia of our time.
>>>>> 
>>>> 
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