X-Git-Url: http://git.vanrenterghem.biz/git.ikiwiki.info.git/blobdiff_plain/47cff6eda61701a6142b40b93991fd9a84f065c4..1f95e9b4d953ffdcb496bd9e995aefedc4a33f0e:/doc/todo/tracking_bugs_with_dependencies.mdwn diff --git a/doc/todo/tracking_bugs_with_dependencies.mdwn b/doc/todo/tracking_bugs_with_dependencies.mdwn index 04d5f2ba0..5f3ece290 100644 --- a/doc/todo/tracking_bugs_with_dependencies.mdwn +++ b/doc/todo/tracking_bugs_with_dependencies.mdwn @@ -1,3 +1,5 @@ +[[!tag patch patch/core]] + I like the idea of [[tips/integrated_issue_tracking_with_ikiwiki]], and I do so on several wikis. However, as far as I can tell, ikiwiki has no functionality which can represent dependencies between bugs and allow pagespecs to select based on dependencies. For instance, I can't write a pagespec which selects all bugs with no dependencies on bugs not marked as done. --[[JoshTriplett]] > I started having a think about this. I'm going to start with the idea that expanding @@ -257,6 +259,9 @@ account all comments above (which doesn't mean it is above reproach :) ). --[[W >>>> To fix that I'll need to pass a reference to that array into pagespec_makeperl. >>>> I think I can then do the same thing to $params{specFuncs}. -- [[Will]] +>>>>> You're right -- I did not think the recursive case through. +>>>>> --[[Joey]] + > * Seems that the only reason `match_glob` has to check for `~` is > because when a named spec appears in a pagespec, it is translated > to `match_glob("~foo")`. If, instead, `pagespec_makeperl` checked @@ -283,13 +288,18 @@ account all comments above (which doesn't mean it is above reproach :) ). --[[W >>>> and - define(aStar, a*) and link(aStar) + define(aStar, a*) and link(~aStar) >>>> In the first case, we want the pagespec to match any page that links to a page matching the glob. >>>> In the second case, we want the pagespec to match any page that links to a page matching the named spec. >>>> match_link() was already doing existential part. The patches to this code were simply to remove the `lc()` >>>> call from the named pagespec name. Can that `lc` be removed entirely? -- [[Will]] +>>>>> I think we could get rid of it. `bestlink` will lc it itself +>>>>> if the uppercase version does not exist; `match_glob` matches +>>>>> insensitively. +>>>>> --[[Joey]] + > * Generally, the need to modify `match_*` functions so that they > check for and handle named pagespecs seems suboptimal, if > only because there might be others people may want to use named @@ -307,6 +317,36 @@ account all comments above (which doesn't mean it is above reproach :) ). --[[W >>> But if a plugin adds its own match function, it has >>> to explicitly call that code to support named pagespecs. +>>>> Yes, and it can do that in just three lines of code. But if we automatically check for named pagespecs all the time we +>>>> potentially break any matching function that doesn't accept pages, or wants to use multiple arguments. + +>>>>> 3 lines of code, plus the functions called become part of the API, +>>>>> don't forget about that.. +>>>>> +>>>>> Yes, I think that is the tradeoff, the question is whether to export +>>>>> the additional complexity needed for that flexability. +>>>>> +>>>>> I'd be suprised if multiple argument pagespecs become necessary.. +>>>>> with the exception of this patch there has been no need for them yet. +>>>>> +>>>>> There are lots of pagespecs that take data other than pages, +>>>>> indeed, that's really the common case. So far, none of them +>>>>> seem likely to take data that starts with a `~`. Perhaps +>>>>> the thing to do would be to check if `~foo` is a known, +>>>>> named pagespec, and if not, just pass it through unchanged. +>>>>> Then there's little room for ambiguity, and this also allows +>>>>> pagespecs like `glob(~foo*)` to match the literal page `~foo`. +>>>>> (It will make pagespec_merge even harder tho.. see below.) +>>>>> --[[Joey]] + +>>>>>> I've already used multi-argument pagespec match functions in +>>>>>> my data plugin. It is used for having different types of links. If +>>>>>> you want to have multiple types of links, then the match function +>>>>>> for them needs to take both the link name and the link type. +>>>>>> I'm trying to think of a way we could have both - automatically +>>>>>> handle the existential case unless the function indicates somehow +>>>>>> that it'll do it itself. Any ideas? -- [[Will]] + > * I need to check if your trick to avoid infinite recursion > works if there are two named specs that recursively > call one-another. I suspect it does, but will test this @@ -320,7 +360,10 @@ account all comments above (which doesn't mean it is above reproach :) ). --[[W > --[[Joey]] >> There is one issue that I've been thinking about that I haven't raised anywhere (or checked myself), and that is how this all interacts with page dependencies. ->> Firstly, I'm not sure anymore that the `pagespec_merge` function will continue to work in all cases. +>> +>>> I've moved the discussion of that to [[dependency_types]]. --[[Joey]] +>> +>> I'm not sure anymore that the `pagespec_merge` function will continue to work in all cases. >>> The problem I can see there is that if two pagespecs >>> get merged and both use `~foo` but define it differently, @@ -328,84 +371,68 @@ account all comments above (which doesn't mean it is above reproach :) ). --[[W >>> it shouldn't (but I haven't verified that really happens). >>> That could certianly be a show-stopper. --[[Joey]] +>>>> I think this can happen in the new closure based code. I don't think this could happen in the old code. -- [[Will]] + >>>> Even if that works, this is a good argument for having a syntactic difference between named pagespecs and normal pages. >>>> If you're joining two pagespecs with 'or', you don't want a named pagespec in the first part overriding a page name in the >>>> second part. Oh, and I assume 'or' has the right operator precedence that "a and b or c" is "(a and b) or c", and not "a and (b or c)" -- [[Will]] >>>>> Looks like its bracketed in the code anyway... -- [[Will]] ->> Secondly, it seems that there are two types of dependency, and ikiwiki ->> currently only handles one of them. The first type is "Rebuild this ->> page when any of these other pages changes" - ikiwiki handles this. ->> The second type is "rebuild this page when set of pages referred to by ->> this pagespec changes" - ikiwiki doesn't seem to handle this. I ->> suspect that named pagespecs would make that second type of dependency ->> more important. I'll try to come up with a good example. -- [[Will]] - ->>> Hrm, I was going to build an example of this with backlinks, but it ->>> looks like that is handled as a special case at the moment (line 458 of ->>> render.pm). I'll see if I can breapk ->>> things another way. Fixing this properly would allow removal of that special case. -- [[Will]] - ->>>> I can't quite understand the distinction you're trying to draw ->>>> between the two types of dependencies. Backlinks are a very special ->>>> case though and I'll be suprised if they fit well into pagespecs. ->>>> --[[Joey]] - ->>>>> The issue is that the existential pagespec matching allows you to build things that have similar ->>>>> problems to backlinks. ->>>>> e.g. the following inline: - - \[[!inline pages="define(~done, link(done)) and link(~done)" archive=yes]] - ->>>>> includes any page that links to a page that links to done. Now imagine I add a new link to 'done' on ->>>>> some random page somewhere - a page which some other page links to which didn't previously get included - the set of pages accepted by the pagespec, and hence the set of ->>>>> pages inlined, will change. But, there is no dependency anywhere on the page that I altered, so ->>>>> ikiwiki will not rebuild the page with the inline in it. What is happening is that the page that I altered affects ->>>>> the set of pages matched by the pagespec without itself being matched by the pagespec, and hence included in the dependency list. - ->>>>> To make this work well, I think you need to recognise two types of dependencies for each page (and no ->>>>> special cases for particular types of links, eg backlinks). The first type of dependency says, "The content of ->>>>> this page depends upon the content of these other pages". The `add_depends()` in the shortcuts ->>>>> plugin is of this form: any time the shortcuts page is edited, any page with a shortcut on it ->>>>> is rebuilt. The inline plugin also needs to add dependencies of this form to detect when the inlined ->>>>> content changes. By contrast, the map plugin does not need a dependency of this form, because it ->>>>> doesn't actually care about the content of any pages, just which pages it needs to include (which we'll handle next). - ->>>>> The second type of dependency says, "The content of this page depends upon the exact set of pages matched ->>>>> by this pagespec". The first type of dependency was about the content of some pages, the second type is about ->>>>> which pages get matched by a pagespec. This is the type of dependency tracking that the map plugin needs. ->>>>> If the set of pages matched by map pagespec changes, then the page with the map on it needs to be rebuilt to show a different list of pages. ->>>>> Inline needs this type of dependency as well as the previous type - This type handles a change in which pages ->>>>> are inlined, the previous type handles a change in the content of any of those pages. Shortcut does not need this type of ->>>>> dependency. Most of the places that use `add_depends()` seem to need this type of dependency rather than the first type. - ->>>>> Implementation Details: The first type of dependency can be handled very similarly to the current ->>>>> dependency system. You just need to keep a list of pages that the content depends upon. You could ->>>>> keep that list as a pagespec, but if you do this you might want to check that the pagespec doesn't change, ->>>>> possibly by adding a dependency of the second type along with the dependency of the first type. - ->>>>> The second type of dependency is a little more tricky. For each page, we'd need a list of pagespecs that ->>>>> the page depended on, and for each pagespec you'd want to store the list of pages that currently match it. ->>>>> On refresh, you'd need to check each pagespec to see if the set of pages that match it has changed, and if ->>>>> that set has changed, then rebuild the dependent page(s). Oh, and for this second type of dependency, I ->>>>> don't think you can merge pagespecs. If I wanted to know if either "\*" or "link(done)" changes, then just checking ->>>>> to see if the set of pages matched by "\* or link(done)" changes doesn't work. - ->>>>> The current system works because even though you usually want dependencies of the second type, the set of pages ->>>>> referred to by a pagespec can only change if one of those pages itself changes. i.e. A dependency check of the ->>>>> first type will catch a dependency change of the second type with current pagespecs. ->>>>> This doesn't work with backlinks, and it doesn't work with existential matching. Backlinks are currently special-cased. I don't know ->>>>> how to special-case existential matching - I suspect you're better off just getting the dependency tracking right. - ->>>>> I also tried to come up with other possible solutions: e.g. can we find the dependencies for a pagespec? That ->>>>> would be the set of pages where a change on one of those pages could lead to a change in the set of pages matched by the pagespec. ->>>>> For old-style pagespecs without backlinks, the dependency set for a pagespec is the same as the set of pages the pagespec matches. ->>>>> Unfortunately, with existential matching, the set of pages that each ->>>>> pagespec depends upon can quickly become "*", which is not very useful. -- [[Will]] +>>>> Perhaps the thing to do is to have a `clear_defines()` +>>>> function, then merging `A` and `B` yields `(A) or (clear_defines() and (B))` +>>>> That would deal with both the cases where `A` and `B` differently +>>>> define `~foo` as well as with the case where `A` defines `~foo` while +>>>> `B` uses it to refer to a literal page. +>>>> --[[Joey]] + +>>>>> I don't think this will work with the new patch, and I don't think it was needed with the old one. +>>>>> Under the old patch, pagespec_makeperl() generated a string of unevaluated, self-contained, perl +>>>>> code. When a new named pagespec was defined, a recursive call was made to get the perl code +>>>>> for the pagespec, and then that code was used to add something like `$params{specFuncs}->{name} = sub {recursive code} and ` +>>>>> to the result of the calling function. This means that at pagespec testing time, when this code is executed, the +>>>>> specFuncs hash is built up as the pagespec is checked. In the case of the 'or' used above, later redefinitions of +>>>>> a named pagespec would have redefined the specFunc at the right time. It should have just worked. However... + +>>>>> Since my original patch, you started using closures for security reasons (and I can see the case for that). Unfortunately this +>>>>> means that the generated perl code is no longer self-contained - it needs to be evaluated in the same closure it was generated +>>>>> so that it has access to the data array. To make this work with the recursive call I had two options: a) make the data array a +>>>>> reference that I pass around through the pagespec_makeperl() functions and have available when the code is finally evaluated +>>>>> in pagespec_translate(), or b) make sure that each pagespec is evaluated in its correct closure and a perl function is returned, not a +>>>>> string containing unevaluated perl code. + +>>>>> I went with option b). I did it in such a way that the hash of specfuncs is built up at translation time, not at execution time. This +>>>>> means that with the new code you can call specfuncs that get defined out of order: + + ~test and define(~test, blah) + +>>>>> but it also means that using a simple 'or' to join two pagespecs wont work. If you do something like this: + + ~test and define(~test, foo) and define(~test, baz) + +>>>>> then the last definition (baz) takes precedence. +>>>>> In the process of writing this I think I've come up with a way to change this back the way it was, still using closures. -- [[Will]] + +>>> My [[remove-pagespec-merge|should_optimise_pagespecs]] branch has now +>>> solved all this by deleting the offending function :-) --[[smcv]] + + Patch updated to use closures rather than inline generated code for named pagespecs. Also includes some new use of ErrorReason where appropriate. -- [[Will]] +> * Perl really doesn't need forward declarations, honest! + +>> It complained (warning, not error) when I didn't use the forward declaration. :( + +> * I have doubts about memoizing the anonymous sub created by +> `pagespec_translate`. + +>> This is there explicitly to make sure that runtime is polynomial and not exponential. + +> * Think where you wrote `+{}` you can just write `{}` + +>> Possibly :) -- [[Will]] + ---- diff --git a/IkiWiki.pm b/IkiWiki.pm @@ -433,7 +460,7 @@ Patch updated to use closures rather than inline generated code for named pagesp - \w+\([^\)]*\) # command(params) + define\(\s*~\w+\s*,((\([^()]*\)) | ([^()]+))+\) # define(~specName, spec) - spec can contain parens 1 deep + | - + \w+\([^())]*\) # command(params) - params cannot contain parens + + \w+\([^()]*\) # command(params) - params cannot contain parens | [^\s()]+ # any other text )