4.10. Viewing Differences
One of the commonest requirements in project development is to
see what has changed. You might want to look at the differences
between two revisions of the same file, or the differences between
two separate files.
TortoiseSVN provides a built-in tool named
TortoiseMerge for viewing differences of
text files. For viewing differences of image files, TortoiseSVN
also has a tool named TortoiseIDiff.
Of course, you can use your own favourite diff program if you
like.
- Local changes
If you want to see what changes you
have made in your working copy, just use the explorer
context menu and select
→ .
- Difference to another branch/tag
If you want to see what has changed on trunk (if you are
working on a branch) or on a specific branch (if you are
working on trunk), you can use the explorer context menu.
Just hold down the Shift key while you
right click on the file. Then select
→ . In the following dialog, specify the URL in
the repository with which you want to compare your local
file to.
You can also use the repository browser and select two
trees to diff, perhaps two tags, or a branch/tag and trunk.
The context menu there allows you to compare them
using .
Read more in Section 4.10.3, “Comparing Folders”.
- Difference from a previous revision
If you want to see the difference between a particular
revision and your working copy, use the Revision Log
dialog, select the revision of interest, then select
from the context menu.
If you want to see the difference between the last committed
revision and your working copy, assuming that the working copy
hasn't been modified, just right click on the file. Then select
→ .
This will perform a diff between the revision before
the last-commit-date (as recorded in your working copy) and the
working BASE. This shows you the last change made to that file
to bring it to the state you now see in your working copy.
It will not show changes newer than your working copy.
- Difference between two previous revisions
If you want to see the difference between two revisions
which are already committed, use the Revision Log
dialog and select the two revisions you want to compare
(using the usual Ctrl-modifier).
Then select
from the context menu.
If you did this from the revision log for a folder,
a Compare Revisions dialog appears, showing a list
of changed files in that folder. Read more in
Section 4.10.3, “Comparing Folders”.
- All changes made in a commit
If you want to see the changes made to all files
in a particular revision in one view, you can
use Unified-Diff output (GNU patch format). This shows
only the differences with a few lines of context. It
is harder to read than a visual file compare, but will
show all the changes together. From the Revision Log
dialog select the revision of interest, then select
from the context menu.
- Difference between files
If you want to see the differences between two different
files, you can do that directly in explorer by selecting
both files (using the usual Ctrl-modifier).
Then from the explorer context menu select
→ .
- Difference between WC file/folder and a URL
If you want to see the differences between a file in your
working copy, and a file in any Subversion repository,
you can do that directly in explorer by selecting the
file then holding down the Shift key whilst
right clicking to obtain the context menu. Select
→ .
You can do the same thing for a working copy folder.
TortoiseMerge shows these differences in the same way
as it shows a patch file - a list of changed files which
you can view one at a time.
- Difference with blame information
If you want to see not only the differences but also the author,
revision and date that changes were made, you can combine the
diff and blame reports from within the revision log dialog.
Read Section 4.23.2, “Blame Differences” for more detail.
- Difference between folders
The built-in tools supplied with TortoiseSVN do not support
viewing differences between directory hierarchies. But if you
have an external tool which does support that feature, you can
use that instead. In Section 4.10.6, “External Diff/Merge Tools”
we tell you about some tools which we have used.
If you have configured a third party diff tool, you can use
Shift when selecting the Diff command to
use the alternate tool.
Read Section 4.30.5, “External Program Settings” to
find out about configuring other diff tools.
4.10.2. Line-end and Whitespace Options
Sometimes in the life of a project you might change the line endings
from CRLF to LF, or you may
change the indentation of a section. Unfortunately this will mark
a large number of lines as changed, even though there is no change
to the meaning of the code. The options here will help to manage
these changes when it comes to comparing and applying differences.
You will see these settings in the Merge and
Blame dialogs, as well as in the settings for
TortoiseMerge.
Ignore line endings
excludes changes which are due solely to difference in line-end style.
Compare whitespaces
includes all changes in indentation and inline whitespace as
added/removed lines.
Ignore whitespace changes
excludes changes which are due solely to a change in the
amount or type of whitespace, e.g. changing the indentation
or changing tabs to spaces. Adding whitespace where there
was none before, or removing a whitespace completely is still
shown as a change.
Ignore all whitespaces
excludes all whitespace-only changes.
Naturally, any line with changed content is always included in
the diff.
4.10.3. Comparing Folders
When you select two trees within the repository browser, or when
you select two revisions of a folder in the log dialog, you can
→ .
This dialog shows a list of all files which have changed and allows
you to compare or blame them individually using context menu.
You can export a change tree, which is useful
if you need to send someone else your project tree structure, but
containing only the files which have changed.
This operation works on the selected files only, so you need
to select the files of interest - usually that means all of them -
and then
→ .
You will be prompted for a location to save the change tree.
You can also export the list of changed files
to a text file using
→ .
If you want to export the list of files and
the actions (modified, added, deleted) as well, you can do that using
→ .
The button at the top allows you to change the direction of
comparison. You can show the changes need to get from A to B,
or if you prefer, from B to A.
The buttons with the revision numbers on can be used to change to a
different revision range. When you change the range, the list of items
which differ between the two revisions will be updated automatically.
If the list of filenames is very long, you can use the search box
to reduce the list to filenames containing specific text. Note that
a simple text search is used, so if you want to restrict the list
to C source files you should enter .c rather than
*.c.
4.10.4. Diffing Images Using TortoiseIDiff
There are many tools available for diffing text files, including our
own TortoiseMerge, but we often find ourselves wanting to see how
an image file has changed too. That's why we created TortoiseIDiff.
→
for any of the common image file formats will start TortoiseIDiff
to show image differences. By default the images are displayed side-by-side
but you can use the View menu or toolbar to switch to a top-bottom
view instead, or if you prefer, you can overlay the images and pretend
you are using a lightbox.
Naturally you can also zoom in and out and pan around the image.
You can also pan the image simply by left-dragging it.
If you select the Link images together option,
then the pan controls (scrollbars, mousewheel) on both images are linked.
An image info box shows details about the image file, such as the
size in pixels, resolution and colour depth. If this box gets in the
way, use
→
to hide it.
You can get the same information in a tooltip if you hover the mouse
over the image title bar.
When the images are overlaid, the relative intensity of the images
(alpha blend) is controlled by a slider control at the left side.
You can click anywhere in the slider to set the blend directly, or you
can drag the slider to change the blend interactively.
Ctrl+Shift-Wheel to change the blend.
The button above the slider toggles between 0% and 100% blends, and
if you double click the button, the blend toggles automatically every
second until you click the button again. This can be useful when looking
for multiple small changes.
Sometimes you want to see a difference rather than a blend. You might
have the image files for two revisions of a printed circuit board and
want to see which tracks have changed. If you disable alpha blend mode,
the difference will be shown as an XOR of the pixel
colour values. Unchanged areas will be plain white and changes will be
coloured.
4.10.5. Diffing Office Documents
When you want to diff non-text documents you normally have to use the
software used to create the document as it understands the file format.
For the commonly used Microsoft Office and Open Office suites there
is indeed some support for viewing differences and TortoiseSVN
includes scripts to invoke these with the right settings when you
diff files with the well-known file extensions. You can check which
file extensions are supported and add your own by going to
→
and clicking Advanced in the
External Programs section.
![[Tip]](/images/svn/tip.png) | Problems with Office 2010 |
|---|
If you installed the Click-to-Run version of
Office 2010 and you try to diff documents you may get an error message
from Windows Script Host something like this:
“ActiveX component can't create object: word.Application”.
It seems you have to use the MSI-based version of Office to get
the diff functionality.
|
4.10.6. External Diff/Merge Tools
If the tools we provide don't do what you need, try one of the many
open-source or commercial programs available. Everyone has their own
favourites, and this list is by no means complete, but here are a few
that you might consider:
- WinMerge
WinMerge
is a great open-source diff tool which can also
handle directories.
- Perforce Merge
Perforce is a commercial RCS, but you can download the
diff/merge tool for free. Get more information from
Perforce
.
- KDiff3
KDiff3 is a free diff tool which can also handle
directories. You can download it from
here
.
- SourceGear DiffMerge
SourceGear Vault is a commercial RCS, but you can download the
diff/merge tool for free. Get more information from
SourceGear
.
- ExamDiff
ExamDiff Standard is freeware. It can handle
files but not directories.
ExamDiff Pro is shareware and adds a number
of goodies including directory diff and editing
capability.
In both flavours, version 3.2 and above can handle
unicode. You can download them from
PrestoSoft
.
- Beyond Compare
Similar to ExamDiff Pro, this is an excellent shareware
diff tool which can handle directory diffs and unicode.
Download it from
Scooter Software
.
- Araxis Merge
Araxis Merge is a useful commercial tool for diff and merging
both files and folders. It does three-way comparison in merges
and has synchronization links to use if you've changed the order
of functions. Download it from
Araxis
.
Read Section 4.30.5, “External Program Settings” for information
on how to set up TortoiseSVN to use these tools.
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