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Programs like gedit don't merge. Period. Yet I can still use it to resolve a merge conflict. In Photoshop you would do this by opening both images, and visua

by LukeShu 11y ago

Programs like gedit don't merge. Period. Yet I can still use it to resolve a merge conflict. In Photoshop you would do this by opening both images, and visually comparing them to see what's different, then copying the appropriate parts from one to another. Instead of just visually comparing them, you might combine them into one file as separate layers, and use a transform to see the difference. If the tool doesn't support that, use ImageMagick to generate a graphical diff (either the `compare` or `compose` commands), and then copy the relevant parts from one to another. We have fancy tools to help us, but fundamentally, merging is a /human/ operation, that requires human judgment to see how multiple sets of changes can be made to coexist. And that doesn't require a tool (though it can certainly help).

Xorlev 11y ago
> In Photoshop you would do this by opening both images, and visually comparing them to see what's different, then copying the appropriate parts from one to another. Good luck. The point the parent was trying to make is that the lock operation of SVN was quite convenient for preventing a dual-edit scenario of assets that aren't easy to merge like 3D meshes, scenes, PSDs, etc.. It's easy to sit in the ivory tower of text merge resolution given how easy it is in comparison. The atom of change in other tools are quite a bit less obvious. Sure you can diff a mesh, but merging usually just means redoing it or picking one or the other.
vvanders 11y ago
Cool, how do you merge After Effects, Autocad, Cinema 4D, Unreal 3 Packages, Illustrator, Sketch, Blender, XSi Lightwave or any other of the production packages that I've seen used in shipping actual products? What happens if no one used layers in your Photoshop file and collapsed history to save performance? There's a reason Pixar and most mid-large game dev studios use Perforce or a similar tech, it's because fundamentally you need locking if you're working with binary assets.
- brazzledazzle 11y ago
  I can't imagine this is intended to compete head-to-head with something like Perforce. As you've pointed out it simply can't. But for a repo that's mostly code with binary assets that get updated occasionally it's probably a god-send.
- drewm1980 11y ago
  Your intelligent merge tool has access to the file history. If one user modifies a layer, and the other one squashes them down, in the merge you probably want to apply the changes in that order, even if it's out-of-order chronologically. If the file format has a full edit history baked in, great; even more info for the intelligent merge. Maybe the in-file history can even be kept in sync with the repository level history. In the current ecosystem you probably need locking for your sanity, but some day software will suck less.
TeMPOraL 11y ago
> In Photoshop you would do this by opening both images, and visually comparing them to see what's different, (...) Yeah, good luck with that. With software like Photoshop, not every change is obvious or easily visible. Maybe the other guy tweaked blending parameters of a layer, or reconfigured some effects layers. Or modified the document metadata. Or did thousands other things that are not immediately visible, or for which it is hard to determine the sequence changes should be reapplied. Maybe you can manually merge the two files to some reasonably good approximation of the intended result, but you can't never be sure you didn't miss something important. Merging tools for text files show enough information for you to know when you've seen every change made. You can't have that with complex binary formats used by graphics programs, mostly because those formats were never explicitly designed to support merging.
- LukeShu 11y ago
  > Yeah, good luck with that. With software like Photoshop, not every change is obvious or easily visible. Well, there's the time-honored technique of "rapidly switch between windows that are zoomed to the same place." But, more rigorously, I mentioned a way to do this; there are tools that can do a diff of raster images--which is what you are making at the end of the day with Photoshop. Sure it can't tell you what blurring parameters someone changed, but you can see that the blur changed, then you can go look at the parameters. > Or did thousands other things that are not immediately visible The trickiness of that situation isn't unique to binary formats. It comes up with code too. > Maybe you can manually merge the two files to some reasonably good approximation of the intended result, but you can't never be sure you didn't miss something important. That's just as true with code as it is with other formats! > because those formats were never explicitly designed to support merging. Neither was text. We just ended up making some tools that were reasonably decent at it. I've been there, I've done that. I've done the 3-way merge with Photoshop files, and resolved the conflicts with 2 different people working on an InDesign file, and broken down to running `diff` on hexdumps of PDF files. Resolving merges with things that don't have nice tools for it isn't fun. But it's a /lie/ to claim that a conflict for binary formats is "game over, you're just going to steamroll someone's work, there is no path to merge resolution". It's not a fun path, but it's not game over. Which is all I was really trying to refute. (aside: It's interesting to me that this chain of comments went from being upvoted last night to downvoted this morning.)
theseoafs 11y ago
So your suggestion for merging two 3D models that were made in Blender is to use ImageMagick compare to see what's different and then copy the differences from one Blender file to the other?

by LukeShu 11y ago

Xorlev 11y ago

> In Photoshop you would do this by opening both images, and visually comparing them to see what's different, then copying the appropriate parts from one to another. Good luck. The point the parent was trying to make is that the lock operation of SVN was quite convenient for preventing a dual-edit scenario of assets that aren't easy to merge like 3D meshes, scenes, PSDs, etc.. It's easy to sit in the ivory tower of text merge resolution given how easy it is in comparison. The atom of change in other tools are quite a bit less obvious. Sure you can diff a mesh, but merging usually just means redoing it or picking one or the other.

vvanders 11y ago

Cool, how do you merge After Effects, Autocad, Cinema 4D, Unreal 3 Packages, Illustrator, Sketch, Blender, XSi Lightwave or any other of the production packages that I've seen used in shipping actual products? What happens if no one used layers in your Photoshop file and collapsed history to save performance? There's a reason Pixar and most mid-large game dev studios use Perforce or a similar tech, it's because fundamentally you need locking if you're working with binary assets.

brazzledazzle 11y ago
I can't imagine this is intended to compete head-to-head with something like Perforce. As you've pointed out it simply can't. But for a repo that's mostly code with binary assets that get updated occasionally it's probably a god-send.
drewm1980 11y ago
Your intelligent merge tool has access to the file history. If one user modifies a layer, and the other one squashes them down, in the merge you probably want to apply the changes in that order, even if it's out-of-order chronologically. If the file format has a full edit history baked in, great; even more info for the intelligent merge. Maybe the in-file history can even be kept in sync with the repository level history. In the current ecosystem you probably need locking for your sanity, but some day software will suck less.

TeMPOraL 11y ago

> In Photoshop you would do this by opening both images, and visually comparing them to see what's different, (...) Yeah, good luck with that. With software like Photoshop, not every change is obvious or easily visible. Maybe the other guy tweaked blending parameters of a layer, or reconfigured some effects layers. Or modified the document metadata. Or did thousands other things that are not immediately visible, or for which it is hard to determine the sequence changes should be reapplied. Maybe you can manually merge the two files to some reasonably good approximation of the intended result, but you can't never be sure you didn't miss something important. Merging tools for text files show enough information for you to know when you've seen every change made. You can't have that with complex binary formats used by graphics programs, mostly because those formats were never explicitly designed to support merging.

LukeShu 11y ago
> Yeah, good luck with that. With software like Photoshop, not every change is obvious or easily visible. Well, there's the time-honored technique of "rapidly switch between windows that are zoomed to the same place." But, more rigorously, I mentioned a way to do this; there are tools that can do a diff of raster images--which is what you are making at the end of the day with Photoshop. Sure it can't tell you what blurring parameters someone changed, but you can see that the blur changed, then you can go look at the parameters. > Or did thousands other things that are not immediately visible The trickiness of that situation isn't unique to binary formats. It comes up with code too. > Maybe you can manually merge the two files to some reasonably good approximation of the intended result, but you can't never be sure you didn't miss something important. That's just as true with code as it is with other formats! > because those formats were never explicitly designed to support merging. Neither was text. We just ended up making some tools that were reasonably decent at it. I've been there, I've done that. I've done the 3-way merge with Photoshop files, and resolved the conflicts with 2 different people working on an InDesign file, and broken down to running `diff` on hexdumps of PDF files. Resolving merges with things that don't have nice tools for it isn't fun. But it's a /lie/ to claim that a conflict for binary formats is "game over, you're just going to steamroll someone's work, there is no path to merge resolution". It's not a fun path, but it's not game over. Which is all I was really trying to refute. (aside: It's interesting to me that this chain of comments went from being upvoted last night to downvoted this morning.)

theseoafs 11y ago

So your suggestion for merging two 3D models that were made in Blender is to use ImageMagick compare to see what's different and then copy the differences from one Blender file to the other?