-There is an issue where an initial "inline" directive would be
-translated correctly but subsequent inlines of the same page would
-result in the raw contents of the ".po" file (ie. starting with the raw
-copyright headers!) being inserted into the page instead.
-
-For example, given a "index.mdwn" containing:
-
- \[[!inline pages="inline" raw="yes"]]
- \[[!inline pages="inline" raw="yes"]]
-
-… and an "index.de.po" of:
-
- msgid "\[[!inline pages=\"inline\" raw=\"yes\"]]\n"
- msgstr "\[[!inline pages=\"inline.de\" raw=\"yes\"]]\n"
-
-… together with an "inline.mdwn" of:
-
- This is inlined content.
-
-… and an "inline.de.po" of:
-
- msgid "This is inlined content."
- msgstr "This is German inlined content."
-
-§
-
-This would result in the following translation:
-
- This is the inlined content.
- # SOME DESCRIPTIVE TITLE
- # Copyright (C) YEAR Free Software Foundation, Inc.
- # This file is distributed under the same license as the PACKAGE package.
- # FIRST AUTHOR <EMAIL@ADDRESS>, YEAR.
-
-… instead of (of course)
-
- This is the inlined content.
- This is the inlined content.
-
-[[Initially proposed patch from Chris Lamb|20180628-patch.txt]]
-
-[[!tag patch]]
-
-> Thank you Chris! I've reviewed the patch (with my "original author of the po plugin" hat on) and it looks good to me. I'm not 100% sure about `alreadyfiltered` being the best name for something that's not a predicated anymore but it's good enough. Then I wore my end-user hat and confirmed that with Chris' patch applied, the reproducer we had for this bug at Tails works fine. So IMO we're good to go and I recommend to apply this patch. Thanks in advance! -- [[intrigeri]]
-
-> Any update on getting this merged? — [[lamby]], Fri, 24 Aug 2018 12:36:37 +0200
-
-> Indeed, would love to see this merged! What might be the next steps here? — [[lamby]], Thu, 18 Oct 2018 17:57:37 -0400
-
-> I've filed this in Debian GNU/Linux at <https://bugs.debian.org/911356> — [[lamby]], Thu, 18 Oct 2018 20:18:58 -0400
-
->> As I said on the Debian bug, I think we badly need test coverage for
->> this sort of thing, otherwise it *will* regress. The po plugin is
->> relatively complicated and hooks into lots of places in ikiwiki,
->> and I don't think any of the active ikiwiki maintainers use it
->> themselves, which means it can easily break (or have pre-existing
->> bugs) without anyone realising.
->>
->> For now I've added a failing test-case for this particular bug.
->> --[[smcv]]
-
----
-
-Review from [[smcv]]:
-
-The patch attached to the Debian bug and the patch pasted here (which
-I've moved to an attachment) appear to be different, but I'm not going to
-do a line-by-line review of the patches and their differences for now
-because I'm not sure their approach is fully correct.
-
-As we know, the two hardest things in computer science are naming, cache
-invalidation and off-by-one errors. Unfortunately this patch has issues
-with naming and cache invalidation. It's effectively turning the
-`alreadyfiltered` mechanism into a cache of memoized results of calling
-`po_to_markup()` on pages' content, keyed by the page name and the
-`destpage`, which is either the page name again or the name of a page
-into which the `page` is to be inlined (even though the result of
-`po_to_markup()` doesn't actually vary with the `destpage`).
-
-This naturally raises the usual concerns about having a cache:
-
-* How large does it grow?
-* Do we invalidate it every time we need to?
-* Do we even need it?
-
-The cache size is mainly a concern for large wikis being rebuilt. If you
-have a wiki with 1000 translated pages in 3 languages each, each of which
-is inlined into an average of one other page, then by the time you finish
-a rebuild you'll be holding 6000 translated pages in memory. If we change
-the `alreadyfiltered` mechanism to be keyed by the page name and not the
-(page, destpage) pair, that drops to 3000, but that's still
-O(pages \* languages) which seems like a lot. As a general design
-principle, ikiwiki tries not to hold full content in RAM for more than
-the currently-processed page.
-
-We invalidate the `alreadyfiltered` for a (page, page) pair in an
-editcontent hook, and we never invalidate (page, destpage) pairs for
-page != destpage at all. Are we sure there is no other circumstance in
-which the content of a page can change?
-
-One of the things I tried doing for a simple solution was to remove the
-cache altogether, because I wasn't sure why we had this `alreadyfiltered`
-mechanism in the first place. This passes tests, which suggests that
-either the `alreadyfiltered` mechanism is unnecessary, or our regression
-test coverage for `po` is insufficient.
-
-Looking back at the history of the `po` plugin, it seems that the
-`alreadyfiltered` mechanism was introduced (under a different name,
-with less abstraction) by [[intrigeri]] in commit 1e874b3f:
-
-```
-po plugin[filter]: avoid converting more than once per destfile
-
-Only the first filter function call on a given {page,destpage} must convert it
-from the PO file, subsequent calls must leave the passed $content unmodified.
-
-Else, preprocessing loops are the rule.
-```
-
-I don't understand this. Under what circumstances would we pass content
-through the filter hooks, and then pass it back through the same filter
-hooks? Can we not do that, instead? If at all possible we should at
-least have test coverage for the situation where this happened (but I
-can't add this without knowing what it was).
-
-I feel as though it should be an invariant that the output of a filter
-hook is never passed back through filter hooks: otherwise every filter
-hook would have to be able to be able to detect and skip processing
-its own output, which is not necessarily even possible. For instance,
-suppose you had a plugin with a filter that turned tab-separated text
-files into `<table>` markup: every HTML file that doesn't contain tabs
-is trivially a TSV file with one column, so you can't know whether a
-blob of text is TSV or HTML.
-
-I wondered whether the loops referenced in 1e874b3f might have been
-fixed in 192ce7a2:
-
- remove unnecessary and troublesome filter calls
-
- This better defines what the filter hook is passed, to only be the raw,
- complete text of a page. Not some snippet, or data read in from an
- unrelated template.
-
- Several plugins that filtered text that originates from an (already
- filtered) page were modified not to do that. Note that this was not
- done very consistently before; other plugins that receive text from a
- page called preprocess on it w/o first calling filter.
-
- The template plugin gets text from elsewhere, and was also changed not to
- filter it. That leads to one known regression -- the embed plugin cannot
- be used to embed stuff in templates now. But that plugin is deprecated
- anyway.
-
- Later we may want to increase the coverage of what is filtered. Perhaps
- a good goal would be to allow writing a filter plugin that filters
- out unwanted words, from any input. We're not there yet; not only
- does the template plugin load unfiltered text from its templates now,
- but so can the table plugin, and other plugins that use templates (like
- inline!). I think we can cross that bridge when we come to it. If I wanted
- such a censoring plugin, I'd probably make it use a sanitize hook instead,
- for the better coverage.
-
- For now I am concentrating on the needs of the two non-deprecated users
- of filter. This should fix bugs/po_vs_templates, and it probably fixes
- an obscure bug around txt's use of filter for robots.txt.
-
-but I'm not sure that any of the redundant filtering removed in that
-commit was actually relevant to `po` users?
-
-[[intrigeri]], can you shed any light on this?
-
-Naming is the easy part of this review: the `alreadyfiltered` family of
-functions are not named like cache getter/setter functions. This could
-be resolved by renaming.
+[[!meta redir="bugs/po:_second_or_subsequent_inline_of_translated_page_inlines_.po_file__44___not_translated_content"]]