X-Git-Url: http://git.vanrenterghem.biz/git.ikiwiki.info.git/blobdiff_plain/48584247f814ea6d2383efd86383477b84663d22..6daf1f6f3ce9adee3bf3ba327064ad0d6df39038:/doc/bugs/template_creation_error.mdwn?ds=inline

diff --git a/doc/bugs/template_creation_error.mdwn b/doc/bugs/template_creation_error.mdwn
index 8bdda3729..aae75a304 100644
--- a/doc/bugs/template_creation_error.mdwn
+++ b/doc/bugs/template_creation_error.mdwn
@@ -194,63 +194,64 @@ Please, let me know what to do to avoid this kind of error.
 >>>>>
 >>>>> --[[chrysn]]
 
->>>>>> [[!template id=gitbranch author="[[smcv]]" branch=smcv/ready/templatebody
-         browse=http://git.pseudorandom.co.uk/smcv/ikiwiki.git/shortlog/refs/heads/ready/templatebody]]
->>>>>> [[!tag patch]]
->>>>>> Branch and directive renamed to `ready/templatebody` as chrysn suggested.
->>>>>> It's on-by-default now (or will be if that branch is merged).
->>>>>> Joey, any chance you could review this?
->>>>>>
->>>>>> There is one known buglet: `template_syntax.t` asserts that the entire
->>>>>> file is a valid HTML::Template, whereas it would ideally be doing the
->>>>>> same logic as IkiWiki itself. I don't think that's serious. --[[smcv]]
+----
 
->>>>>>> Looking over this, I notice it adds a hash containing all scanned
->>>>>>> files. This seems to me to be potentially a scalability problem on
->>>>>>> rebuild of a site with many pages. Ikiwiki already keeps a lot
->>>>>>> of info in memory, and this adds to it, for what is a fairly
->>>>>>> minor reason. It seems to me there should be a way to avoid this. --[[Joey]] 
+[[!template id=gitbranch author="[[smcv]]" branch=smcv/ready/templatebody
+  browse=http://git.pseudorandom.co.uk/smcv/ikiwiki.git/shortlog/refs/heads/ready/templatebody]]
+[[!tag patch]]
+Branch and directive renamed to `ready/templatebody` as chrysn suggested.
+It's on-by-default now (or will be if that branch is merged).
+Joey, any chance you could review this?
 
->>>>>>>> Maybe. Are plugins expected to cope with scanning the same
->>>>>>>> page more than once? If so, it's just a tradeoff between
->>>>>>>> "spend more time scanning the template repeatedly" and
->>>>>>>> "spend more memory on avoiding it", and it would be OK to
->>>>>>>> omit that, or reduce it to a set of scanned *templates*
->>>>>>>> (in practice that would mean scanning each template twice
->>>>>>>> in a rebuild). --s
+There is one known buglet: `template_syntax.t` asserts that the entire
+file is a valid HTML::Template, whereas it would ideally be doing the
+same logic as IkiWiki itself. I don't think that's serious. --[[smcv]]
 
->>>>>>>>> [Commit f7303db5](http://source.ikiwiki.branchable.com/?p=source.git;a=commitdiff;h=f7303db5)
->>>>>>>>> suggests that scanning the same page more than once is problematic,
->>>>>>>>> so that solution is probably not going to work.
->>>>>>>>>
->>>>>>>>> The best idea I've come up with so far is to track whether
->>>>>>>>> we're in the scan or render phase. If we're in the scan
->>>>>>>>> phase, I think we do need to keep track of which pages
->>>>>>>>> we've scanned, so we don't do them again? (Or perhaps that's
->>>>>>>>> unnecessary - commit f7303db5 removed a scan call that's in
->>>>>>>>> the render phase.) If we're in the render phase, we can assume
->>>>>>>>> that all changed pages have been scanned already, so we can
->>>>>>>>> drop the contents of `%scanned` and rely on a single boolean
->>>>>>>>> flag instead.
->>>>>>>>>
->>>>>>>>> `%scanned` is likely to be no larger than `%rendered`, which
->>>>>>>>> we already track, and whose useful lifetime does not overlap
->>>>>>>>> with `%scanned` now. I was tempted to merge them both and call
->>>>>>>>> the result `%done_in_this_phase`, but that would lead to really
->>>>>>>>> confusing situations if a bug led to `render` being called sooner
->>>>>>>>> than it ought to be.
->>>>>>>>>
->>>>>>>>> My ulterior motive here is that I would like to formalize
->>>>>>>>> the existence of different phases of wiki processing - at the
->>>>>>>>> moment there are at least two phases, namely "it's too soon to
->>>>>>>>> match pagespecs reliably" and "everything has been scanned,
->>>>>>>>> you may use pagespecs now", but those phases don't have names,
->>>>>>>>> so [[plugins/write]] doesn't describe them.
->>>>>>>>>
->>>>>>>>> I'm also considering adding warnings
->>>>>>>>> if people try to match a pagespec before scanning has finished,
->>>>>>>>> which can't possibly guarantee the right result, as discussed in
->>>>>>>>> [[conditional_preprocess_during_scan]]. My `wip-too-soon` branch
->>>>>>>>> is a start towards that; the docwiki builds successfully, but
->>>>>>>>> the tests that use IkiWiki internals also need updating to
->>>>>>>>> set `$phase = PHASE_RENDER` before they start preprocessing. --s
+> Looking over this, I notice it adds a hash containing all scanned
+> files. This seems to me to be potentially a scalability problem on
+> rebuild of a site with many pages. Ikiwiki already keeps a lot
+> of info in memory, and this adds to it, for what is a fairly
+> minor reason. It seems to me there should be a way to avoid this. --[[Joey]] 
+
+>> Maybe. Are plugins expected to cope with scanning the same
+>> page more than once? If so, it's just a tradeoff between
+>> "spend more time scanning the template repeatedly" and
+>> "spend more memory on avoiding it", and it would be OK to
+>> omit that, or reduce it to a set of scanned *templates*
+>> (in practice that would mean scanning each template twice
+>> in a rebuild). --s
+>>> [Commit f7303db5](http://source.ikiwiki.branchable.com/?p=source.git;a=commitdiff;h=f7303db5)
+>>> suggests that scanning the same page more than once is problematic,
+>>> so that solution is probably not going to work.
+>>>
+>>> The best idea I've come up with so far is to track whether
+>>> we're in the scan or render phase. If we're in the scan
+>>> phase, I think we do need to keep track of which pages
+>>> we've scanned, so we don't do them again? (Or perhaps that's
+>>> unnecessary - commit f7303db5 removed a scan call that's in
+>>> the render phase.) If we're in the render phase, we can assume
+>>> that all changed pages have been scanned already, so we can
+>>> drop the contents of `%scanned` and rely on a single boolean
+>>> flag instead.
+>>>
+>>> `%scanned` is likely to be no larger than `%rendered`, which
+>>> we already track, and whose useful lifetime does not overlap
+>>> with `%scanned` now. I was tempted to merge them both and call
+>>> the result `%done_in_this_phase`, but that would lead to really
+>>> confusing situations if a bug led to `render` being called sooner
+>>> than it ought to be.
+>>>
+>>> My ulterior motive here is that I would like to formalize
+>>> the existence of different phases of wiki processing - at the
+>>> moment there are at least two phases, namely "it's too soon to
+>>> match pagespecs reliably" and "everything has been scanned,
+>>> you may use pagespecs now", but those phases don't have names,
+>>> so [[plugins/write]] doesn't describe them.
+>>>
+>>> I'm also considering adding warnings
+>>> if people try to match a pagespec before scanning has finished,
+>>> which can't possibly guarantee the right result, as discussed in
+>>> [[conditional_preprocess_during_scan]]. My `wip-too-soon` branch
+>>> is a start towards that; the docwiki builds successfully, but
+>>> the tests that use IkiWiki internals also need updating to
+>>> set `$phase = PHASE_RENDER` before they start preprocessing. --s