# Extension dependency not found

**URL:** <https://discourse.slicer.org/t/extension-dependency-not-found/5872>\
**Category:** Development\
**Created:** [February 21, 2019, 5:41pm UTC](https://discourse.slicer.org/t/extension-dependency-not-found/5872 "2019-02-21T17:41:32Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![adamrankin](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/adamrankin/32/155_2.png) [@adamrankin](https://discourse.slicer.org/u/adamrankin)\
**Post date:** [February 21, 2019, 5:41pm UTC](https://discourse.slicer.org/t/extension-dependency-not-found/5872/1 "2019-02-21T17:41:32Z")

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Hello all,

Looking into why our extension didn’t build:  
[http://slicer.cdash.org/viewConfigure.php?buildid=1518975](http://slicer.cdash.org/viewConfigure.php?buildid=1518975)

Is there something obvious I’m missing? I added the dependency to SlicerVirtualReality in EXTENSION\_DEPENDS

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**Author:** ![Sunderlandkyl](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/sunderlandkyl/32/79987_2.png) [@Sunderlandkyl](https://discourse.slicer.org/u/Sunderlandkyl)\
**Post date:** [February 21, 2019, 6:15pm UTC](https://discourse.slicer.org/t/extension-dependency-not-found/5872/2 "2019-02-21T18:15:07Z")

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Possibly because SlicerVirtualReality is not listed as a dependency in the ExtensionsIndex?

> <https://github.com/Slicer/ExtensionsIndex/blob/master/SlicerVASST.s4ext>

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**Author:** ![jcfr](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/jcfr/32/17825_2.png) [@jcfr](https://discourse.slicer.org/u/jcfr)\
**Post date:** [February 21, 2019, 6:17pm UTC](https://discourse.slicer.org/t/extension-dependency-not-found/5872/3 "2019-02-21T18:17:41Z")

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> [@Sunderlandkyl](#):
>
> Possibly because SlicerVirtualReality is not listed as a dependency in the ExtensionsIndex?

Indeed, without this .. the extension build system doesn’t know which folder to pass along.

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**Author:** ![adamrankin](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/adamrankin/32/155_2.png) [@adamrankin](https://discourse.slicer.org/u/adamrankin)\
**Post date:** [February 21, 2019, 7:02pm UTC](https://discourse.slicer.org/t/extension-dependency-not-found/5872/4 "2019-02-21T19:02:11Z")

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Ah, I thought the dependencies were detected from EXTENSION\_DEPENDS. Ok, I’ll fix that.

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<div class="post-metadata">

**Author:** ![jcfr](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/jcfr/32/17825_2.png) [@jcfr](https://discourse.slicer.org/u/jcfr)\
**Post date:** [February 21, 2019, 7:18pm UTC](https://discourse.slicer.org/t/extension-dependency-not-found/5872/5 "2019-02-21T19:18:00Z")

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Indirectly yes.

(1) Metadata are listed in CMakeLists.txt -\> (2) generate description file in build directory -\> (3) description file added to the extension index.

In a nutshell, it is important to keep information consistent between description file and CMakeLists.txt.

Also, since the build system need to know an extension dependency before configuring it … it can not only be in the extension CMakeLists.txt, it needs to be available by some other way.