Update idf_tools.py (IDFGH-17849)

[max-allan]

Description

See issue #14901

The idf_tools.py was using http.client in a way that would fail silently with a short read from the network

Related

Fixes #14901

Testing

Ran the install.sh script where it was previously failing and it didn't fail.

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Checklist

Before submitting a Pull Request, please ensure the following:

• 🚨 This PR does not introduce breaking changes.
• All CI checks (GH Actions) pass.
• [na] Documentation is updated as needed.
• [na] Tests are updated or added as necessary.
• Code is well-commented, especially in complex areas.
• Git history is clean — commits are squashed to the minimum necessary.

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Note

Medium Risk
Changes the core download path used by install.sh and tool installs; HTTP Range resume depends on server support, though failures surface as explicit errors rather than silent truncation.

Overview
Fixes incomplete ESP-IDF tool downloads when the connection drops before the full Content-Length is read—CPython can return an empty read instead of raising, which previously left corrupt partial files.

urlretrieve_ctx now loops up to 8 attempts: after a short read it warns, backs off (capped exponential sleep), and reopens the URL with an HTTP Range: bytes={read}- request, appending to the same output file. Resume requires a 206 response; otherwise it raises ContentTooShortError. File handle lifecycle is wrapped in try/finally so the destination file is always closed.

Adds urllib.request.Request for Range requests and expands the docstring to describe the behavior.

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[dobairoland]

@max-allan Thanks for the contribution. The linked issue hasn't been addressed because in the meantime idf_tools.py have been deprecated and the default installation method since v6.0 is EIM (https://docs.espressif.com/projects/esp-idf/en/release-v6.0/esp32/get-started/macos-setup.html). EIM can also be used for older v5.x releases if the issue occurs with idf_tools.py.

Honestly, I don't think it would be worth the effort (yours or ours) to make this merge-ready and backport (handle minimum required Python for each release branch - as you can see the pre-commit checks are not passing).