fix: Typeguard cannot check the protocol#4986
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Versions 3.0 and higher of `typeguard` can't check the jsii protocol interfaces and produce a noisy warning. Because `constructs` hadn't been updated for a while, and it had been generated with an old version of `jsii-pacmak` that was forcing `typeguard` to `2.13`, no-one had noticed all the changes to `pacmak` that try to support a newer version of `typeguard`, because in practice it never ended up being installed (all CDK projects will install `constructs` which was keeping `typeguard` at an old version). Revert to that old version, and stick at it until we can fix up our generated Python bindings to be more modern.
mrgrain
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Nov 19, 2025
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This reverts commits 937e204 and cba7046. After investigation, the user was correct to question these changes. PR aws#4986 (commit e9b53ec) pinned typeguard to 2.13.3 specifically because "Versions 3.0 and higher of typeguard can't check the jsii protocol interfaces and produce a noisy warning" (aws/constructs#2825). The root cause: jsii generates Python Protocol interfaces (IRole, IVpc, etc.) that are NOT marked with @runtime_checkable. Typeguard 3.x/4.x strictly enforces this, producing warnings like "Typeguard cannot check the IRole protocol because it is a non-runtime protocol." In typeguard 4.3.0+, some cases produce errors that break deployments (aws#4669). While PR aws#4611 (August 2024) added runtime version detection and the __protocol_attrs__ workaround, this does NOT eliminate the warnings. Simply reverting PR aws#4986 without addressing the underlying Protocol checking issue was incorrect. To properly support modern typeguard, we would need to either: 1. Mark all generated Protocol interfaces as @runtime_checkable, or 2. Skip type checking for Protocol interfaces entirely, or 3. Wait for a typeguard upstream fix Until one of these approaches is implemented, the pin to typeguard==2.13.3 should remain. Co-authored-by: qodfathr <16322190+qodfathr@users.noreply.github.com>
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Versions 3.0 and higher of
typeguardcan't check the jsii protocol interfaces and produce a noisy warning.Because
constructshadn't been updated for a while, and it had been generated with an old version ofjsii-pacmakthat was forcingtypeguardto2.13, no-one had noticed all the changes topacmakthat try to support a newer version oftypeguard, because in practice it never ended up being installed (all CDK projects will installconstructswhich was keepingtypeguardat an old version).Revert to that old version, and stick at it until we can fix up our generated Python bindings to be more modern.
Closes aws/constructs#2825
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