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fix(r8): Synthesize file name for foreign members and classes without sourceFile annotation #70

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Merged
romtsn merged 4 commits into from
Dec 18, 2025
Merged

fix(r8): Synthesize file name for foreign members and classes without sourceFile annotation #70

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d561f7b
fix(r8): Synthesize file name for foreign members and classes wihtou …
romtsn Dec 17, 2025
deaa064
Correctly synthesize Kotlin filenames
romtsn Dec 17, 2025
c69474a
Add typealias for members lookup
romtsn Dec 18, 2025
7805511
Fix inlined methods from Kt
romtsn Dec 18, 2025
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129 changes: 89 additions & 40 deletions src/cache/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -72,6 +72,7 @@
mod debug;
mod raw;

use std::borrow::Cow;
use std::cmp::Ordering;
use std::fmt::Write;

Expand All @@ -83,6 +84,16 @@ use crate::{java, stacktrace, DeobfuscatedSignature, StackFrame, StackTrace, Thr

pub use raw::{ProguardCache, PRGCACHE_VERSION};

/// Result of looking up member mappings for a frame.
/// Contains: (members, prepared_frame, rewrite_rules, had_mappings, outer_source_file)
type MemberLookupResult<'data> = (
&'data [raw::Member],
StackFrame<'data>,
Vec<RewriteRule<'data>>,
bool,
Option<&'data str>,
);

/// Errors returned while loading/parsing a serialized [`ProguardCache`].
///
/// After a `ProguardCache` was successfully parsed via [`ProguardCache::parse`], an Error that occurs during
Expand Down Expand Up @@ -311,21 +322,18 @@ impl<'data> ProguardCache<'data> {
}

/// Finds member entries for a frame and collects rewrite rules without building frames.
/// Returns (member_slice, prepared_frame, rewrite_rules, had_mappings).
fn find_members_and_rules(
&'data self,
frame: &StackFrame<'data>,
) -> Option<(
&'data [raw::Member],
StackFrame<'data>,
Vec<RewriteRule<'data>>,
bool,
)> {
) -> Option<MemberLookupResult<'data>> {
let class = self.get_class(frame.class)?;
let original_class = self
.read_string(class.original_name_offset)
.unwrap_or(frame.class);

// Get the outer source file for synthesis
let outer_source_file = self.read_string(class.file_name_offset).ok();

let mut prepared_frame = frame.clone();
prepared_frame.class = original_class;

Expand Down Expand Up @@ -376,7 +384,13 @@ impl<'data> ProguardCache<'data> {
}
}

Some((mapping_entries, prepared_frame, rewrite_rules, had_mappings))
Some((
mapping_entries,
prepared_frame,
rewrite_rules,
had_mappings,
outer_source_file,
))
}

/// Remaps a single stack frame through the complete processing pipeline.
Expand Down Expand Up @@ -413,7 +427,7 @@ impl<'data> ProguardCache<'data> {

let effective = self.prepare_frame_for_mapping(frame, carried_outline_pos);

let Some((members, prepared_frame, rewrite_rules, had_mappings)) =
let Some((members, prepared_frame, rewrite_rules, had_mappings, outer_source_file)) =
self.find_members_and_rules(&effective)
else {
return Some(RemappedFrameIter::empty());
Expand All @@ -432,6 +446,7 @@ impl<'data> ProguardCache<'data> {
members.iter(),
skip_count,
had_mappings,
outer_source_file,
))
}

Expand Down Expand Up @@ -746,6 +761,8 @@ pub struct RemappedFrameIter<'r, 'data> {
skip_count: usize,
/// Whether there were mapping entries (for should_skip determination).
had_mappings: bool,
/// The source file of the outer class for synthesis.
outer_source_file: Option<&'data str>,
}

impl<'r, 'data> RemappedFrameIter<'r, 'data> {
Expand All @@ -754,6 +771,7 @@ impl<'r, 'data> RemappedFrameIter<'r, 'data> {
inner: None,
skip_count: 0,
had_mappings: false,
outer_source_file: None,
}
}

Expand All @@ -763,11 +781,13 @@ impl<'r, 'data> RemappedFrameIter<'r, 'data> {
members: std::slice::Iter<'data, raw::Member>,
skip_count: usize,
had_mappings: bool,
outer_source_file: Option<&'data str>,
) -> Self {
Self {
inner: Some((cache, frame, members)),
skip_count,
had_mappings,
outer_source_file,
}
}

Expand All @@ -782,9 +802,9 @@ impl<'r, 'data> RemappedFrameIter<'r, 'data> {
fn next_inner(&mut self) -> Option<StackFrame<'data>> {
let (cache, frame, members) = self.inner.as_mut()?;
if frame.parameters.is_none() {
iterate_with_lines(cache, frame, members)
iterate_with_lines(cache, frame, members, self.outer_source_file)
} else {
iterate_without_lines(cache, frame, members)
iterate_without_lines(cache, frame, members, self.outer_source_file)
}
}
}
Expand All @@ -806,6 +826,7 @@ fn iterate_with_lines<'a>(
cache: &ProguardCache<'a>,
frame: &mut StackFrame<'a>,
members: &mut std::slice::Iter<'_, raw::Member>,
outer_source_file: Option<&str>,
) -> Option<StackFrame<'a>> {
for member in members {
// skip any members which do not match our frames line
Expand All @@ -814,7 +835,7 @@ fn iterate_with_lines<'a>(
{
continue;
}
// parents of inlined frames don’t have an `endline`, and
// parents of inlined frames don't have an `endline`, and
// the top inlined frame need to be correctly offset.
let line = if member.original_endline == u32::MAX
|| member.original_endline == member.original_startline
Expand All @@ -828,22 +849,19 @@ fn iterate_with_lines<'a>(
.read_string(member.original_class_offset)
.unwrap_or(frame.class);

let file = if member.original_file_offset != u32::MAX {
let file: Option<Cow<'_, str>> = if member.original_file_offset != u32::MAX {
let Ok(file_name) = cache.read_string(member.original_file_offset) else {
continue;
};

if file_name == "R8$$SyntheticClass" {
extract_class_name(class)
extract_class_name(class).map(Cow::Borrowed)
} else {
Some(file_name)
Some(Cow::Borrowed(file_name))
}
} else if member.original_class_offset != u32::MAX {
// when an inlined function is from a foreign class, we
// don’t know the file it is defined in.
None
} else {
frame.file
// Synthesize from class name (input filename is not reliable)
synthesize_source_file(class, outer_source_file).map(Cow::Owned)
};

let Ok(method) = cache.read_string(member.original_name_offset) else {
Expand All @@ -866,6 +884,7 @@ fn iterate_without_lines<'a>(
cache: &ProguardCache<'a>,
frame: &mut StackFrame<'a>,
members: &mut std::slice::Iter<'_, raw::Member>,
outer_source_file: Option<&str>,
) -> Option<StackFrame<'a>> {
let member = members.next()?;

Expand All @@ -875,10 +894,13 @@ fn iterate_without_lines<'a>(

let method = cache.read_string(member.original_name_offset).ok()?;

// Synthesize from class name (input filename is not reliable)
let file = synthesize_source_file(class, outer_source_file).map(Cow::Owned);

Some(StackFrame {
class,
method,
file: None,
file,
line: 0,
parameters: frame.parameters,
method_synthesized: member.is_synthesized(),
Expand All @@ -891,6 +913,31 @@ fn extract_class_name(full_path: &str) -> Option<&str> {
after_last_period.split('$').next()
}

/// Synthesizes a source file name from a class name.
/// For Kotlin top-level classes ending in "Kt", the suffix is stripped and ".kt" is used.
/// Otherwise, the extension is derived from the reference file, defaulting to ".java".
/// For example: ("com.example.MainKt", Some("Other.java")) -> "Main.kt" (Kt suffix takes precedence)
/// For example: ("com.example.Main", Some("Other.kt")) -> "Main.kt"
/// For example: ("com.example.MainKt", None) -> "Main.kt"
/// For inner classes: ("com.example.Main$Inner", None) -> "Main.java"
fn synthesize_source_file(class_name: &str, reference_file: Option<&str>) -> Option<String> {
let base = extract_class_name(class_name)?;

// For Kotlin top-level classes (ending in "Kt"), always use .kt extension and strip suffix
// This takes precedence over reference_file since Kt suffix is a strong Kotlin indicator
if base.ends_with("Kt") && base.len() > 2 {
let kotlin_base = &base[..base.len() - 2];
return Some(format!("{}.kt", kotlin_base));
}

// If we have a reference file, derive extension from it
if let Some(ext) = reference_file.and_then(|f| f.rfind('.').map(|pos| &f[pos..])) {
return Some(format!("{}{}", base, ext));
}

Some(format!("{}.java", base))
}

/// Converts a Java class name to its JVM descriptor format.
///
/// For example, `java.lang.NullPointerException` becomes `Ljava/lang/NullPointerException;`.
Expand Down Expand Up @@ -929,6 +976,8 @@ fn compute_skip_count(rewrite_rules: &[RewriteRule<'_>], thrown_descriptor: Opti

#[cfg(test)]
mod tests {
use std::borrow::Cow;

use crate::{ProguardMapping, StackFrame, StackTrace, Throwable};

use super::raw::ProguardCache;
Expand All @@ -955,15 +1004,15 @@ com.example.MainFragment$onActivityCreated$4 -> com.example.MainFragment$g:
class: "com.example.MainFragment$g",
method: "onClick",
line: 2,
file: Some("SourceFile"),
file: Some(Cow::Borrowed("SourceFile")),
parameters: None,
method_synthesized: false,
},
StackFrame {
class: "android.view.View",
method: "performClick",
line: 7393,
file: Some("View.java"),
file: Some(Cow::Borrowed("View.java")),
parameters: None,
method_synthesized: false,
},
Expand All @@ -977,7 +1026,7 @@ com.example.MainFragment$onActivityCreated$4 -> com.example.MainFragment$g:
class: "com.example.MainFragment$g",
method: "onClick",
line: 1,
file: Some("SourceFile"),
file: Some(Cow::Borrowed("SourceFile")),
parameters: None,
method_synthesized: false,
}],
Expand All @@ -986,13 +1035,13 @@ com.example.MainFragment$onActivityCreated$4 -> com.example.MainFragment$g:
};
let expect = "\
com.example.MainFragment$RocketException: Crash!
at com.example.MainFragment$Rocket.fly(<unknown>:85)
at com.example.MainFragment$onActivityCreated$4.onClick(SourceFile:65)
at com.example.MainFragment$Rocket.fly(MainFragment.java:85)
at com.example.MainFragment$onActivityCreated$4.onClick(MainFragment.java:65)
at android.view.View.performClick(View.java:7393)
Caused by: com.example.MainFragment$EngineFailureException: Engines overheating
at com.example.MainFragment$Rocket.startEngines(<unknown>:90)
at com.example.MainFragment$Rocket.fly(<unknown>:83)
at com.example.MainFragment$onActivityCreated$4.onClick(SourceFile:65)\n";
at com.example.MainFragment$Rocket.startEngines(MainFragment.java:90)
at com.example.MainFragment$Rocket.fly(MainFragment.java:83)
at com.example.MainFragment$onActivityCreated$4.onClick(MainFragment.java:65)\n";

let mapping = ProguardMapping::new(mapping.as_bytes());
let mut cache = Vec::new();
Expand Down Expand Up @@ -1031,13 +1080,13 @@ Caused by: com.example.MainFragment$d: Engines overheating

let expect = "\
com.example.MainFragment$RocketException: Crash!
at com.example.MainFragment$Rocket.fly(<unknown>:85)
at com.example.MainFragment$onActivityCreated$4.onClick(SourceFile:65)
at com.example.MainFragment$Rocket.fly(MainFragment.java:85)
at com.example.MainFragment$onActivityCreated$4.onClick(MainFragment.java:65)
at android.view.View.performClick(View.java:7393)
Caused by: com.example.MainFragment$EngineFailureException: Engines overheating
at com.example.MainFragment$Rocket.startEngines(<unknown>:90)
at com.example.MainFragment$Rocket.fly(<unknown>:83)
at com.example.MainFragment$onActivityCreated$4.onClick(SourceFile:65)
at com.example.MainFragment$Rocket.startEngines(MainFragment.java:90)
at com.example.MainFragment$Rocket.fly(MainFragment.java:83)
at com.example.MainFragment$onActivityCreated$4.onClick(MainFragment.java:65)
... 13 more\n";

let mapping = ProguardMapping::new(mapping.as_bytes());
Expand Down Expand Up @@ -1069,7 +1118,7 @@ java.lang.NullPointerException: Boom
at a.a(SourceFile:4)";
let expect = "\
java.lang.NullPointerException: Boom
at some.Class.caller(SourceFile:7)
at some.Class.caller(Class.java:7)
";

assert_eq!(cache.remap_stacktrace(input).unwrap(), expect);
Expand All @@ -1094,7 +1143,7 @@ java.lang.NullPointerException: Boom
at a.call(SourceFile:4)";
let expected_npe = "\
java.lang.NullPointerException: Boom
at some.Class.outer(SourceFile:7)
at some.Class.outer(Class.java:7)
";
assert_eq!(cache.remap_stacktrace(input_npe).unwrap(), expected_npe);

Expand All @@ -1103,7 +1152,7 @@ java.lang.IllegalStateException: Boom
at a.call(SourceFile:4)";
let expected_ise = "\
java.lang.IllegalStateException: Boom
at some.Class.outer(SourceFile:7)
at some.Class.outer(Class.java:7)
";
assert_eq!(cache.remap_stacktrace(input_ise).unwrap(), expected_ise);
}
Expand Down Expand Up @@ -1135,7 +1184,7 @@ java.lang.NullPointerException: Boom
// not replaced with the original "at a.call(SourceFile:4)"
let expected = "\
java.lang.NullPointerException: Boom
at some.Other.method(SourceFile:30)
at some.Other.method(Other.java:30)
";

let actual = cache.remap_stacktrace(input).unwrap();
Expand Down Expand Up @@ -1169,15 +1218,15 @@ some.Other -> b:
class: "a",
method: "call",
line: 4,
file: Some("SourceFile"),
file: Some(Cow::Borrowed("SourceFile")),
parameters: None,
method_synthesized: false,
},
StackFrame {
class: "b",
method: "run",
line: 5,
file: Some("SourceFile"),
file: Some(Cow::Borrowed("SourceFile")),
parameters: None,
method_synthesized: false,
},
Expand Down
11 changes: 6 additions & 5 deletions src/cache/raw.rs
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Expand Up @@ -313,15 +313,16 @@ impl<'data> ProguardCache<'data> {
.map(|(obfuscated, original)| {
let obfuscated_name_offset = string_table.insert(obfuscated.as_str()) as u32;
let original_name_offset = string_table.insert(original.as_str()) as u32;
let is_synthesized = parsed
.class_infos
.get(original)
.map(|ci| ci.is_synthesized)
.unwrap_or_default();
let class_info = parsed.class_infos.get(original);
let is_synthesized = class_info.map(|ci| ci.is_synthesized).unwrap_or_default();
let file_name_offset = class_info
.and_then(|ci| ci.source_file)
.map_or(u32::MAX, |s| string_table.insert(s) as u32);
let class = ClassInProgress {
class: Class {
original_name_offset,
obfuscated_name_offset,
file_name_offset,
is_synthesized: is_synthesized as u8,
..Default::default()
},
Comment on lines +318 to 328

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@romtsn romtsn Dec 17, 2025

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I don't think anything changed we just started using/supplying file_name_offset

Expand Down
5 changes: 3 additions & 2 deletions src/lib.rs
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Expand Up @@ -25,10 +25,11 @@
//! mapper
//! .remap_frame(&proguard::StackFrame::new("a.a.a.b.c", "a", 13))
//! .collect::<Vec<_>>(),
//! vec![proguard::StackFrame::new(
//! vec![proguard::StackFrame::with_file(
//! "android.arch.core.internal.SafeIterableMap",
//! "eldest",
//! 168
//! 168,
//! "SafeIterableMap.java"
//! )],
//! );
//! ```
Expand Down
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