epubcheck, any software can pass its validiation check?

[pdurrant]

Originally Posted by kovidgoyal

I just want people to realize that having your book passed by epubcheck is a guarantee of precisely nothing.

It's a guarantee that it passes that particular version of epubcheck!

On the other hand, failing to pass epubcheck means that 99 times out of 100 there's something wrong with your ePub. Even though it might still render OK in some readers, it would be better to fix the problems.

[loveangel]

Just so you know: epubcheck is totally meaningless. A file that *passes* epubcheck may or may not work with any given epub renderer. A file that *does not pass* epubcheck may or may not work with any given epub renderer.

The best that could possibly be said about epubcheck (and I wouldn't be comfortable saying this without actual data) is that a file that passes epubcheck may be more likely than a file that does not pass to render correctly with most epub viewers. Even if this were true it would most likely be so because files that tend to pass epubcheck tend, on average, to have extremely simple markup, as they are typically the product of machine translation from some extremely simple format.

What I'm trying to say is that the things that epubcheck checks are those things that it is easiest to write software to check, not those things that are most likely to cause problems, or those things that are most likely to occur in the wild.

What epubcheck is good for, is those situations where you have absolutely no idea why your epub file is not rendering with a particular renderer. In that case, you can try running epubcheck on it and fix the errors it points out. Of course, that may or may not fix your actual problem. And even for this use case, epubcheck is extremely sub-optimal since its error messages are incredibly unhelpful.

That's my epubcheck jeremiad for this week.

Got your point !

[charleski]

Originally Posted by charleski

While it's not perfect (and desperately needs another release)

I'm happy to say I've just found I'm completely wrong there!

epubcheck 1.0.5 was released for download on Feb 18, and should contain a host of fixes. No need to use the old Dec '08 version any more. The earlier Threepress blog post on it left me thinking the actual release was still some time away.

[Jellby]

Originally Posted by kovidgoyal

I just want people to realize that having your book passed by epubcheck is a guarantee of precisely nothing.

But, as pdurrant says, if the book doesn't pass epubcheck, that's a guarantee of even less. It serves, at least, to catch the errors it catches. For me it has been useful to check I have not forgotten to add any file, that the internal links are consistent, that I didn't leave HTML entities in the NCX file, etc. Failure to pass epubcheck means that, if your book does not display fine, you cannot blame the reader

Of course, I'm saying ¬p -> ¬q, that does not imply p -> q

[kovidgoyal]

Originally Posted by Jellby

Failure to pass epubcheck means that, if your book does not display fine, you cannot blame the reader

Yes you can, your file is most likely not displaying in the reader for reasons that have nothing to do with the errors epubcheck is pointing out.

But maybe my perspective on this issue is somewhat different, since I don't hand create EPUB files. Instead I hand create an e-book in TXT or HTML and auto generate the EPUB from that. So things like checking the NCX and OPF files for validity are not important to me, all that's automatically taken care of

[Valloric]

Originally Posted by droople

What I did with Sigil epub file is type in "test" in the text field, without import any external files.

Here is the validation message
ERROR: test.epub/OEBPS/content.opf(6): unfinished element

Originally Posted by awp

This is because some mandatory metadata items are missing.

Originally Posted by pdurrant

It's a design decision not to add random values to the metadata for the required metadata fields.

If you use the metadata editing interface in Sigil, and enter values for the required items, Sigil ePubs pass epubcheck if you also have valid XHTML in the content.

What pdurrant said. Emphasis mine.

[Valloric]

Originally Posted by kovidgoyal

What I'm trying to say is that the things that epubcheck checks are those things that it is easiest to write software to check, not those things that are most likely to cause problems, or those things that are most likely to occur in the wild.

I don't think anyone would disagree with this. Epubcheck will not find the serious errors, but it will find the simple ones. So why not fix the simple ones?

As others have noted, it's a sanity check. Passing epubcheck doesn't mean your file doesn't have problems, but not passing it means it does in 99% of cases.

Again, epubcheck will scream on even trivial things you can safely ignore, but if you're trying to build an error-free epub, why not fix those?

[kovidgoyal]

Originally Posted by Valloric

Again, epubcheck will scream on even trivial things you can safely ignore, but if you're trying to build an error-free epub, why not fix those?

No reason except that you and I and pdurrant and Jellby recognize that these are trivial errors. Most people don't.

[Valloric]

Originally Posted by kovidgoyal

No reason except that you and I and pdurrant and Jellby recognize that these are trivial errors. Most people don't.

But you also said that epubcheck is doing "more harm than good". I strongly disagree with that.

Epubcheck is like a spell checker. It will catch things like "teh" instead of "the", but not "they're" instead of "their", or the more serious grammatical errors. But even within its limited capabilities, a spell checker is extremely useful. Sure, there are those (misguided) people who think that just because their document passes a spell checker it is error-free, but that's not the spell checker's fault.

It's the fault of the bozos who don't know better.

And bashing a spell checker because someone else is a bozo is IMO silly.

[Jellby]

Originally Posted by kovidgoyal

Yes you can, your file is most likely not displaying in the reader for reasons that have nothing to do with the errors epubcheck is pointing out.

In a sense, you are right, the reader's problems are not necessarily related to the problems detected by epubcheck, but if the book is not a valid ePUB file, you should't expect the reader to display it correctly. Make it first a valid ePUB, and you can blame the reader as much as you want

[kovidgoyal]

Originally Posted by Valloric

But you also said that epubcheck is doing "more harm than good". I strongly disagree with that.

And bashing a spell checker because someone else is a bozo is IMO silly.

But epubcheck is a spell checker that does not claim to be a spell checker. It claims to be a grammar checker. I also said that epubcheck should have been named epub-schema-check or something equivalent.

[kovidgoyal]

Originally Posted by Jellby

In a sense, you are right, the reader's problems are not necessarily related to the problems detected by epubcheck, but if the book is not a valid ePUB file, you should't expect the reader to display it correctly. Make it first a valid ePUB, and you can blame the reader as much as you want

In my (rather extensive) experience, they're almost never related to problems detected by epubcheck.

[droople]

Originally Posted by kovidgoyal

But epubcheck is a spell checker that does not claim to be a spell checker. It claims to be a grammar checker. I also said that epubcheck should have been named epub-schema-check or something equivalent.

Do you mean "spell mistake" is not important and you never correct them?

Cheers

[droople]

Originally Posted by Valloric

I don't think anyone would disagree with this. Epubcheck will not find the serious errors, but it will find the simple ones. So why not fix the simple ones?

As others have noted, it's a sanity check. Passing epubcheck doesn't mean your file doesn't have problems, but not passing it means it does in 99% of cases.

Again, epubcheck will scream on even trivial things you can safely ignore, but if you're trying to build an error-free epub, why not fix those?

I strong agree.

[kovidgoyal]

Originally Posted by droople

Do you mean "spell mistake" is not important and you never correct them?

Cheers

No I mean that assuming something is error free because it has no spelling errors is wrong.