dist-apk follows the engine's strip decision: --no-strip and --debug-symbols reach the packed libraries (#649 E5)

Author: Sunrisepeak

dist/apk.cppm

@@ -221,6 +221,16 @@ struct options {
     // drops the symbol table and the debug information -- what the Android
     // Gradle plugin does to every library it packages, and what `mcpp pack`
     // reports it did.
+    //
+    // FROM 0.12.0 THE ENGINE'S DECISION GOVERNS AS WELL. An engine that strips
+    // what the graph built (mcpp 2026.9.16.1, #649 E5) tells a build program
+    // whether this packaging pass strips (`MCPP_PACK_STRIP`, "1" or "0") and
+    // where `--debug-symbols` sends the separated debug information
+    // (`MCPP_PACK_DEBUG_SYMBOLS_DIR`), so `mcpp pack --no-strip` and
+    // `--debug-symbols <dir>` reach the libraries this member packs as they
+    // reach the ones the engine stages. A library is stripped unless either
+    // this option or the engine says to keep it. An older engine publishes
+    // neither variable, and the member strips as before.
     bool keep_debug_symbols = false;
 
     // LEVEL 1, KOTLIN (0.11.0). One or more directories of `.kt` sources,
@@ -1998,10 +2008,24 @@ inline plan plan_for(options opt = {}) {
     }
     const bool inPlaceLibraries = loads_native_libraries_in_place(manifestBytes);
 
+    // THE ENGINE'S STRIP DECISION (0.12.0), read through the environment
+    // rather than an `mcpp::` accessor so the member still builds, and still
+    // strips, under an engine that predates the accessor. See
+    // `options::keep_debug_symbols`.
+    const char* engineStrip = std::getenv("MCPP_PACK_STRIP");
+    const bool engineKeeps = engineStrip && std::string_view(engineStrip) == "0";
+    const char* engineDebugDir = std::getenv("MCPP_PACK_DEBUG_SYMBOLS_DIR");
+    const std::string debugDir = engineDebugDir ? engineDebugDir : "";
+
     // THE BUILD'S OWN llvm-strip (0.11.1): the one beside the compiler mcpp
-    // resolved for this row, the NDK's.
+    // resolved for this row, the NDK's. With a debug-symbols directory,
+    // `llvm-objcopy` beside it separates the debug information first, in the
+    // order the engine's own strip uses (`src/pack/strip.cppm`): a copy of the
+    // debug sections while the library still has them, then the stripped
+    // library with a `.gnu_debuglink` naming that copy.
     std::string llvmStrip;
-    if (!opt.keep_debug_symbols) {
+    std::string llvmObjcopy;
+    if (!opt.keep_debug_symbols && !engineKeeps) {
         const std::string toolchain = mcpp::toolchain_dir();
         const fs::path candidate = fs::path(toolchain) / "bin" / "llvm-strip";
         if (!toolchain.empty() && is_file(candidate.string())) {
@@ -2011,6 +2035,17 @@ inline plan plan_for(options opt = {}) {
                 "mcpp.dist.apk: no llvm-strip beside the toolchain ({}); the native libraries are packed "
                 "with their debug information.", toolchain.empty() ? "none reported" : toolchain).c_str());
         }
+        if (!llvmStrip.empty() && !debugDir.empty()) {
+            const fs::path objcopy = fs::path(toolchain) / "bin" / "llvm-objcopy";
+            if (is_file(objcopy.string())) {
+                llvmObjcopy = objcopy.string();
+            } else {
+                mcpp::warning(std::format(
+                    "mcpp.dist.apk: --debug-symbols names {}, and there is no llvm-objcopy beside the "
+                    "toolchain ({}) to separate the libraries' debug information; they are stripped "
+                    "without it.", debugDir, toolchain).c_str());
+            }
+        }
     }
 
     // ── the temporary staging tree: lib/<abi>/, assets/ ─────────────────
@@ -2047,10 +2082,38 @@ inline plan plan_for(options opt = {}) {
         }
         std::error_code ec;
         fs::create_directories(dst.parent_path(), ec);
+        const std::string leaf = fs::path(so).filename().string();
+        if (!llvmObjcopy.empty()) {
+            // One subdirectory per ABI: a package carries the same library name
+            // once for every ABI, and a flat directory would let the last one
+            // overwrite the others' debug information.
+            const fs::path debugFile = fs::path(debugDir) / abi / (leaf + ".debug");
+            fs::create_directories(debugFile.parent_path(), ec);
+            step keep;
+            keep.id          = std::format("{}:debug:{}:{}", bundle ? "aab" : "apk", abi, leaf);
+            keep.role        = "artifact";
+            keep.description = "LLVM-OBJCOPY --only-keep-debug " + abi + "/" + leaf;
+            keep.output      = debugFile.string();
+            keep.argv        = { llvmObjcopy, "--only-keep-debug", so, keep.output };
+            keep.inputs      = { so };
+            p.steps.push_back(keep);
+
+            step strip;
+            strip.id          = std::format("{}:strip:{}:{}", bundle ? "aab" : "apk", abi, leaf);
+            strip.role        = "artifact";
+            strip.description = "LLVM-OBJCOPY --strip-unneeded " + abi + "/" + leaf;
+            strip.output      = dst.string();
+            strip.argv        = { llvmObjcopy, "--strip-unneeded",
+                                  "--add-gnu-debuglink=" + debugFile.string(), so, strip.output };
+            strip.inputs      = { so, keep.output };
+            p.steps.push_back(strip);
+            libInputs.push_back(strip.output);
+            return;
+        }
         step strip;
-        strip.id          = std::format("{}:strip:{}:{}", bundle ? "aab" : "apk", abi, fs::path(so).filename().string());
+        strip.id          = std::format("{}:strip:{}:{}", bundle ? "aab" : "apk", abi, leaf);
         strip.role        = "artifact";
-        strip.description = "LLVM-STRIP " + abi + "/" + fs::path(so).filename().string();
+        strip.description = "LLVM-STRIP " + abi + "/" + leaf;
         strip.output      = dst.string();
         strip.argv        = { llvmStrip, "--strip-unneeded", "-o", strip.output, so };
         strip.inputs      = { so };

tests/apk-consumer/check-apk-features.sh

@@ -308,3 +308,45 @@ grep -q '\.symtab' sections-l.log || fail "keep_debug_symbols packed a stripped
 unset APK_CONSUMER_KEEP_DEBUG_SYMBOLS
 rm -rf k
 echo "ok: keep_debug_symbols packs the library with its symbol table"
+
+# ── (m),(n) 0.12.0: the engine's strip decision reaches the packed libraries ─
+#
+# An engine that strips what the graph built (mcpp 2026.9.16.1) publishes its
+# decision to the build program, so (m) `mcpp pack --no-strip` packs the library
+# with its symbol table, and (n) `--debug-symbols <dir>` separates its debug
+# information into `<dir>/<abi>/<library>.debug` and leaves a `.gnu_debuglink`
+# in the packed copy. An older engine publishes nothing, so these legs are
+# skipped there; (k) is the behaviour that engine keeps.
+engine_version=$("$MCPP" --version | awk '{print $2}')
+if [ "$(printf '%s\n%s\n' 2026.9.16.1 "$engine_version" | sort -V | head -1)" = 2026.9.16.1 ]; then
+    echo "== (m) mcpp pack --no-strip =="
+    rm -rf target k
+    "$MCPP" pack --format apk --target "$TARGET" --no-strip > pack-m.log 2>&1 || fail "pack --no-strip failed" pack-m.log
+    APK=$(find target -name 'apk-consumer.apk' | head -1)
+    [ -n "$APK" ] || fail "no apk-consumer.apk" pack-m.log
+    mkdir -p k && unzip -q -o "$APK" "$LIB" -d k
+    readelf -S "k/$LIB" > sections-m.log
+    grep -q '\.symtab' sections-m.log || fail "--no-strip packed a stripped library" sections-m.log
+    rm -rf k
+    echo "ok: --no-strip packs the library with its symbol table"
+
+    echo "== (n) mcpp pack --debug-symbols <dir> =="
+    rm -rf target k debug-n
+    DEBUG_DIR="$PWD/debug-n"
+    "$MCPP" pack --format apk --target "$TARGET" --debug-symbols "$DEBUG_DIR" > pack-n.log 2>&1 \
+        || fail "pack --debug-symbols failed" pack-n.log
+    APK=$(find target -name 'apk-consumer.apk' | head -1)
+    [ -n "$APK" ] || fail "no apk-consumer.apk" pack-n.log
+    mkdir -p k && unzip -q -o "$APK" "$LIB" -d k
+    readelf -S "k/$LIB" > sections-n.log
+    if grep -qE '\.symtab|\.debug_' sections-n.log; then fail "the packed library keeps its symbol table or debug information" sections-n.log; fi
+    grep -q '\.gnu_debuglink' sections-n.log || fail "the packed library does not name its debug file" sections-n.log
+    DEBUG_FILE="$DEBUG_DIR/x86_64/libapk-consumer.so.debug"
+    [ -f "$DEBUG_FILE" ] || fail "no $DEBUG_FILE" pack-n.log
+    readelf -S "$DEBUG_FILE" > sections-n-debug.log
+    grep -q '\.debug_' sections-n-debug.log || fail "the separated file carries no debug sections" sections-n-debug.log
+    rm -rf k debug-n
+    echo "ok: --debug-symbols separates the library's debug information and links the packed copy to it"
+else
+    echo "skip: (m),(n) need an engine that publishes MCPP_PACK_STRIP (2026.9.16.1+); this is $engine_version"
+fi