Why doesn't my asmdef Version Define set the symbol?

The Resource string must match a package name exactly (com.unity.netcode.gameobjects). The Expression must match the installed version (e.g. [1.0,99]). Test in Project Settings → Player → Scripting Define Symbols list to verify.

How do I check installed package version?

Window → Package Manager → click the package → Version. Or open Packages/manifest.json. Match the asmdef Expression to that version range.

Can I version-gate code based on Unity version?

Yes. Use UNITY_2022_3_OR_NEWER style defines (built-in). For finer control, write a custom #if UNITY_VERSION_GE(2022,3) macro. asmdef Version Defines target packages, not the engine.

Fix: Unity asmdef Version Defines Not Applied

Quick answer: Resource = exact package name (com.unity.netcode.gameobjects). Expression = SemVer range matching the installed version (e.g. [1.0,99]). Define = the symbol you want. Reimport and check Scripting Define Symbols.

Code wraps a feature in #if NETCODE_INSTALLED. The asmdef Version Define is set up but the symbol never appears in the compile. Likely the Resource or Expression mismatched.

The Symptom

Code under #if SYMBOL never compiles. Other defines work. Editor shows the asmdef Version Define configured.

The Fix

asmdef inspector → Version Defines:
  +
    Resource:      com.unity.netcode.gameobjects   // exact package id
    Expression:    [1.0,99]                            // SemVer range
    Define:        NETCODE_INSTALLED

Click Apply. Reimport the asmdef. The Define is now set when the package version matches the Expression.

SemVer Expressions

1.0.0 exact.
[1.0,2.0) 1.0 inclusive to 2.0 exclusive.
1.0.0-pre.4 with pre-release tags.
[1.0,99] “1.0 or any future” for forward compatibility.

Verifying

Edit a file in the asmdef. #if NETCODE_INSTALLED — should highlight as active in IDE. Or Debug.Log("defined"); inside; appears in console at startup.

“Exact package. SemVer range. Define applies.”

Related Issues

For asmdef circular ref, see circular ref. For Burst permutation, see Burst permutation.

Resource exact. Expression matches. Define lives.