In T241265#5770837, @dcausse wrote:

One problem is that the french stemmer does not conflate venir with its conjugated form venu or venue.
The page Je suis venu te dire que je m'en vais does not have venir meaning that it cannot match the query Je suis venir te dire que je m'en vais.

That make sense, but how does it achieve to find “Sheila (section Je suis venue te dire que je m'en vais (1989))“ as first result?

In T241265#5772399, @Pols12 wrote:

In T241265#5770837, @dcausse wrote:

One problem is that the french stemmer does not conflate venir with its conjugated form venu or venue.
The page Je suis venu te dire que je m'en vais does not have venir meaning that it cannot match the query Je suis venir te dire que je m'en vais.

That make sense, but how does it achieve to find “Sheila (section Je suis venue te dire que je m'en vais (1989))“ as first result?

I think the reason is that venir in its infinitive form is present in the page for Sheila elsewhere. Note that in the section snippet venue is not highlighted. Also the fact that the section snippet is found does not mean that all the words in your query are in this section. The smallest unit is the whole page in search, the section snippet in the search result is just a hint that some words have matched the section name nothing more.
Here venir is found for example in

dans le but de venir en aide aux femmes du Sahel

in the 1983-1989 : Virage artistique section.
On the other hand venir is never found on the page about Gainsbourg's song nor the Jane Birkin album.

Indeed! =)

In fact, I didn’t expect the stemmer achieved to look for “venu” instead of “venir”, but I would think CirrusSearch would try to remove the “venir” keyword to find articles where all other words are in the title.
(Before your explanation, I believed it already did it for finding Sheila article; so I found that bahavior inconsistent.)

In T241265#5773883, @Pols12 wrote:

Indeed! =)

In fact, I didn’t expect the stemmer achieved to look for “venu” instead of “venir”, but I would think CirrusSearch would try to remove the “venir” keyword to find articles where all other words are in the title.
(Before your explanation, I believed it already did it for finding Sheila article; so I found that bahavior inconsistent.)

Oh I see, I should have started with this, yes Cirrus is applying a AND between all words of your query even if the query contains many words like this one.
We have been looking into relaxing this and allowing some words to not appear in the documents found (see T112178) but this work was never finished due to other priorities. We still believe it might be helpful.

So I think the help should be fixed, it currently indicates: “There may be results that do not contain one or more of your search terms.”

Many thanks for your answers, please feel free to close this as T112583 duplicate, or keep it for French stemming tracking.

Is there an open task to track relaxing AND operator between all words?

@Pols12 sadly there are no planned work to add this to CirrusSearch in the foreseeable future, if you believe that CirrusSearch should provide such functionality please feel free to open a task or re-purpose this particular task if you prefer. Thanks!

Note that Wdsearch gadget results already well include “Je suis venu te dire que je m'en vais” pages, but it’s probably T219108.

It was not T219108, but this does not happen anymore: Wikidata search results are now consistent with Wikipedia ones (i.e. it does not achieve to find any result either).