View source for Fixing ARM Compute Library Fetch Error 24 02 Yocto

== ⚠️ Fixing Yocto Fetch Error: arm-compute-library 24.02 (Wrong Git Branch) ==
This page documents a specific fetch error encountered during a Yocto build when retrieving the source code for the '''ARM Compute Library''' recipe version 24.02, and provides the fix using a '''.bbappend''' file.

=== The Error Message ===
The Yocto build fails during the '''do_fetch''' task for the ''arm-compute-library-24.02'' recipe, indicating that the required commit cannot be found in the default branch:
<pre>
WARNING: arm-compute-library-24.02-r0 do_fetch: Failed to fetch URL git://github.com/ARM-software/ComputeLibrary.git;protocol=https;branch=main;name=arm-compute-library, attempting MIRRORS if available
ERROR: arm-compute-library-24.02-r0 do_fetch: Fetcher failure: Unable to find revision bc89a0b690200750040770bda0981f4a37b389c4 in branch main even from upstream
ERROR: arm-compute-library-24.02-r0 do_fetch: Bitbake Fetcher Error: FetchError('Unable to fetch URL from any source.', 'git://github.com/ARM-software/ComputeLibrary.git;protocol=https;branch=main;name=arm-compute-library')
</pre>

=== Root Cause Analysis ===
The specific Git commit hash (`bc89a0b690200750040770bda0981f4a37b389c4`) required by the recipe has been moved on the upstream repository. It no longer resides in the expected '''main''' branch, but has been relocated to the '''archived-releases''' branch. Consequently, the BitBake fetcher, looking only in ''main'', fails to locate the source code.

=== 💡 The Solution: Overriding the Branch with a `.bbappend` ===
The issue is resolved by creating an '''arm-compute-library_24.02.bbappend''' file in your custom meta-layer to explicitly override the default source Uniform Resource Identifier (URI) and point it to the correct Git branch.

==== Step 1: Create the `.bbappend` File ====
Place the override file within the following path structure in your custom meta-layer (e.g., in a directory named `meta-pn-mtk`):
<pre>
<YOUR_CUSTOM_META_LAYER>/recipes-armnn/arm-compute-library/arm-compute-library_24.02.bbappend
</pre>

==== Step 2: Add the Override Content ====
Populate the '''arm-compute-library_24.02.bbappend''' file with the following content. This configuration changes the source branch to '''archived-releases''' while ensuring the correct '''SRCREV''' (commit hash) is used.

<pre>
SRC_URI = "git://github.com/ARM-software/ComputeLibrary.git;protocol=https;branch=archived-releases;name=arm-compute-library \
           file://0001-enable-yocto-build.patch \
           file://0001-Remove-unknown-variables-treated-as-error.patch \
           file://0001-Prefer-to-use-libmali-as-the-provider-of-OpenCL.patch \
           file://0001-remove-clUpdateMutableCommandsKHR-reference.patch \
           "

SRCREV = "bc89a0b690200750040770bda0981f4a37b389c4"
</pre>
* '''<code>SRC_URI</code>''': The URL parameter is modified to specify '''<code>branch=archived-releases</code>'''.
* '''<code>SRCREV</code>''': The exact commit hash is retained to fetch the desired version of the library.

After adding this file, BitBake will use the new branch setting, allowing the source code fetch to succeed on the next build attempt.