Bug in 'hg diff'

[Will Maier]

On Tue, Jul 24, 2007 at 06:58:22PM +0200, Guido Ostkamp wrote:
> >You're misreading -b:
> >
> >   $ hg help diff
> >   [...]
> >    -b --ignore-space-change  ignore changes in the amount of white space
> >                                                    ^^^^^^
> 
> Obviously this help text is very confusing. I would interpret the 
> introduction of new whitespace as a change in the "amount" from 0 to n 
> whitespace chars.

Taken with the explanation for -w, I think it's clear enough, though
I'm not authoritative.

> >-w (which is what I think you want) also works for me:
> >
> >   $ sed -e 's/^This/    This/' testfile > testfile.new && mv testfile.new 
> >   testfile
> >   $ hg diff -b
> >   diff --git a/testfile b/testfile
> >   --- a/testfile
> >   +++ b/testfile
> >   @@ -1,3 +1,3 @@ This is a test.
> >   -This is a test.
> >   -This is another test.
> >   -This is a third test.
> >   +    This is    a test.
> >   +    This is    another test.
> >   +    This is    a third test.
> >   $ hg diff -w
> 
> Maybe you overlooked that the output you listed above is again
> from 'hg diff -b', not '-w' (or it was a mistake copying the stuff
> to the mail).

No -- look at the bottom, where hg diff -w produces no output.
That's the point: you sound like you want to use -w, but you're
using -b. Why don't you use -w instead?

> When I call it with '-w' option, I get
> 
> $ hg diff -w testfile
> diff -r 06a8711119f9 testfile
> --- a/testfile  Mon Jul 23 23:45:23 2007 +0200
> +++ b/testfile  Tue Jul 24 18:42:00 2007 +0200
> @@ -1,3 +1,4 @@ This is a test.
>   This is a test.
> -This is another test.
> -This is a third test.
> +    This is another test.
> +    This is a third test.
> +Blablabla
> 
> This is exactly the same result as with '-b' and it is wrong as
> whitespace is apparently not ignored (I am using hg version
> 4106dde15aed+20070723).

I assume you made other, non-whitespace changes in that cset. In
combination white non-whitespace changes, -w/-b do seem to produce
oddness. My tests were with whitespace-only changes, in which case
the output is as expected.

> It should behave as if called with regular 'diff -w' (without
> 'hg') as listed in my earlier mail.

You can just use regular diff if you'd like; see the extdiff
extension.

-- 

[Will Maier]-----------------[willmaier at ml1.net|http://www.lfod.us/]