[Unsolvable] Constructor call: Variable reuse in ternary operator (Type A - 10 cases)

[devload]

Problem

Same variable is used in both condition and value of ternary operator before constructor call. This prevents safe inlining because the expression would be evaluated twice.

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Affected Files (10 cases)

A-1: RecyclerView.java

File: androidx/recyclerview/widget/RecyclerView.java

public RecyclerView(Context context, AttributeSet attributeSet, int i) {
    Context context2 = context;  // MOVE: copy context to context2
    super(context2, attributeSet, i);
    // context2 may be used in subsequent code
}

A-2: DefaultBHttpServerConnection.java

File: cz/msebera/android/httpclient/impl/DefaultBHttpServerConnection.java

public DefaultBHttpServerConnection(..., ContentLengthStrategy contentLengthStrategy, ...) {
    ContentLengthStrategy contentLengthStrategy3 = contentLengthStrategy;

    super(..., contentLengthStrategy3 == null
        ? DisallowIdentityContentLengthStrategy.INSTANCE
        : contentLengthStrategy3, ...);
    //  ^^^^^^^^^^^^^^^^^^^^^^^ condition  ^^^^^^^^^^^^^^^^^^^^^^^ value

    // contentLengthStrategy3 used after super()
    this.requestParser = (httpMessageParserFactory2 == null ? ... : httpMessageParserFactory2).create(...);
}

A-3, A-4, A-5: DefaultDrmSessionManager.java (3 cases)

File: com/google/android/exoplayer2/drm/DefaultDrmSessionManager.java

public DefaultDrmSessionManager(UUID uuid, ExoMediaDrm<T> exoMediaDrm,
        MediaDrmCallback mediaDrmCallback, HashMap<String, String> map) {
    HashMap<String, String> map2 = map;
    this(uuid, exoMediaDrm, mediaDrmCallback,
        map2 == null ? new HashMap<>() : map2, false, 3);
    //  ^^^^ condition                   ^^^^ value
}

A-6: zzbsq.java

File: com/google/android/gms/internal/ads/zzbsq.java

public zzbsq(Context context, Looper looper, ...) {
    Context applicationContext = context.getApplicationContext();
    super(applicationContext == null ? context : applicationContext, looper, 8, ...);
    //    ^^^^^^^^^^^^^^^^^^ condition   ^^^^^^^^^^^^^^^^^^ value
}

A-7, A-8, A-9, A-10: String.valueOf Pattern (4 cases)

Files: zzga.java, zzwq.java, zzbn.java (2 cases)

zza(String str, Throwable th) {
    String strValueOf = String.valueOf(str);
    super(strValueOf.length() != 0
        ? "CodedOutputStream was writing...".concat(strValueOf)
        : new String("CodedOutputStream was writing..."), th);
    //    ^^^^^^^^^ condition (.length())      ^^^^^^^^^ value (.concat())
}

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DEX Bytecode Analysis

# Example: getApplicationContext pattern
invoke-virtual {p1}, Landroid/content/Context;->getApplicationContext()Landroid/content/Context;
move-result-object v0                    # v0 = result

# v0 used in BOTH condition and value
if-eqz v0, :use_default
move-object v1, v0                       # Use v0 as value
goto :continue

:use_default
move-object v1, p1                       # Use original context

:continue
invoke-direct {p0, v1, ...}, <init>      # super(v1, ...)

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Why Inlining Fails

// Original (with temp variable - VALID bytecode, INVALID Java)
Context appContext = context.getApplicationContext();
super(appContext == null ? context : appContext, ...);

// If we inline (INVALID - method called TWICE!)
super(context.getApplicationContext() == null 
    ? context 
    : context.getApplicationContext(),  // ❌ Second call!
    ...);

Problems with double evaluation:

1. Side effects: Method may modify state
2. Performance: Expensive operations run twice
3. Inconsistency: Results may differ between calls

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Theoretical Solution

Implement side-effect analysis to identify pure expressions:

Expression	Side-effect	Safe to Inline
String.valueOf(str)	None	✅ Yes
map (parameter)	None	✅ Yes
context.getApplicationContext()	Uncertain	⚠️ Risky
contentLengthStrategy (parameter)	None	✅ Yes

Implementation approach:

1. Parameter references → Always safe
2. Known pure functions (String.valueOf, Integer.valueOf, etc.) → Safe
3. General method calls → Require analysis or whitelist

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Status

Partially solvable - Requires side-effect analysis implementation.

Would need to:

1. Build a whitelist of known pure methods
2. Detect direct parameter references
3. Analyze method purity (complex)

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Related

• Main issue: [Fix] Inline optimization for constructor call pattern (Kotlin decompilation) #2760
• PR with partial fix: fix: Inline optimization for constructor call pattern (Kotlin decompilation) #2767