ddns-scripts: fix netcup.com for multiple runs

[flubshi]

📦 Package Details

Maintainer: @feckert
_{(You can find this by checking the history of the package Makefile.)}

Description:

This PR fixes an issue where the netcup DDNS update script fails on subsequent runs due to reassigning a readonly variable. The variable has been changed to a regular assignment to ensure the script can be sourced multiple times without errors.

Additionally, error handling has been improved:

• Several hard failures (write_log 14) have been replaced with soft failures (return 1) to allow the ddns framework to retry updates according to the configured retry policy.
• Hard failures are now reserved for critical issues such as missing dependencies or invalid configuration.
• JSON parsing has been made more robust by replacing cat-based loading with json_load_file, which is the intended method for handling JSON input in this context.

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🧪 Run Testing Details

• OpenWrt Version: OpenWrt 25.12.2 r32802-f505120278
• OpenWrt Target/Subtarget:
• OpenWrt Device: TP-Link Archer C7 v4

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✅ Formalities

• I have reviewed the CONTRIBUTING.md file for detailed contributing guidelines.

If your PR contains a patch:

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  make package/<your-package>/refresh V=s

• It is structured in a way that it is potentially upstreamable
  _{(e.g., subject line, commit description, etc.)
  We must try to upstream patches to reduce maintenance burden.}

[Copilot]

Pull request overview

Note

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Fixes repeatability and retry behavior of the netcup.com DDNS updater by removing a readonly reassignment error, improving JSON loading, and converting several hard-fail exits into retryable failures.

Changes:

• Make __NETCUP_ENDPOINT re-source-safe by removing readonly assignment.
• Use json_load_file for parsing the provider response stored in $DATFILE.
• Convert several hard failures into return 1 paths to allow ddns framework retries.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
net/ddns-scripts/files/usr/lib/ddns/update_netcup_com.sh	Makes the netcup updater safe to source multiple times; improves JSON loading and makes several failures retryable.
net/ddns-scripts/Makefile	Bumps package release to publish the behavior fixes.

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[feckert]

Can you please split this into 3 changes:

• Remove readonly
• Improve json_init with json_init_file
• Update error path

You're wondering why this should be split into separate commits. Here's my explanation:
To split them up makes the patch handling much clearer. Because with the change in the error path, I’m not sure if that might cause problems, as it behaves differently. If that’s causing the problems, I’d like to revert just that change. The other two are definitely fixes or improvements and can be backported to the stable branches as well.

[flubshi]

@feckert Thanks for your reply! I fully understand this. Do you prefer a single PR or should I create a separate PR for the readonly bug?

[feckert]

I am fine with one PR. Only split them up in 3 commits. I have seen that the provider is only available in the master Branch.

[flubshi]

@feckert PR is adjusted. I hope it is now fine as it is.

[feckert]

Thanks merged!