Try out CAP-0071 xdr with xdr ifdefs

.gitmodules

@@ -23,14 +23,11 @@
 	path = lib/spdlog
 	url = https://github.com/gabime/spdlog
 	ignore = dirty
-[submodule "src/protocol-next/xdr"]
-	path = src/protocol-next/xdr
-	url = https://github.com/stellar/stellar-xdr
-	branch = next
+#TODO: change name
 [submodule "src/protocol-curr/xdr"]
 	path = src/protocol-curr/xdr
 	url = https://github.com/stellar/stellar-xdr
-	branch = curr
+	branch = main
 [submodule "src/rust/soroban/p21"]
 	path = src/rust/soroban/p21
 	url = https://github.com/stellar/rs-soroban-env
@@ -50,6 +47,9 @@
 [submodule "src/rust/soroban/p26"]
 	path = src/rust/soroban/p26
 	url = https://github.com/stellar/rs-soroban-env.git
+[submodule "src/rust/soroban/p27"]
+	path = src/rust/soroban/p27
+	url = https://github.com/stellar/rs-soroban-env.git
 [submodule "lib/gperftools"]
 	path = lib/gperftools
 	url = https://github.com/gperftools/gperftools.git

common.mk

@@ -17,11 +17,7 @@ if USE_POSTGRES
 AM_CPPFLAGS += -DUSE_POSTGRES=1 $(libpq_CFLAGS)
 endif # USE_POSTGRES
 
-if ENABLE_NEXT_PROTOCOL_VERSION_UNSAFE_FOR_PRODUCTION
-AM_CPPFLAGS += -I"$(top_builddir)/src/protocol-next"
-else
 AM_CPPFLAGS += -I"$(top_builddir)/src/protocol-curr"
-endif
 
 # Unconditionally add CEREAL_THREAD_SAFE, we always want it.
 AM_CPPFLAGS += -DCEREAL_THREAD_SAFE
@@ -46,3 +42,15 @@ endif # USE_SPDLOG
 if ENABLE_NEXT_PROTOCOL_VERSION_UNSAFE_FOR_PRODUCTION
 AM_CPPFLAGS += -DENABLE_NEXT_PROTOCOL_VERSION_UNSAFE_FOR_PRODUCTION
 endif # ENABLE_NEXT_PROTOCOL_VERSION_UNSAFE_FOR_PRODUCTION
+
+if BUILDING_NEXT_PROTOCOL
+AM_CPPFLAGS += -DBUILDING_NEXT_PROTOCOL
+endif
+
+if ENABLE_CAP_0071
+AM_CPPFLAGS += -DCAP_0071
+endif
+
+if ENABLE_TEST_FEATURE
+AM_CPPFLAGS += -DTEST_FEATURE
+endif

configure.ac

@@ -549,6 +549,24 @@ AC_ARG_ENABLE(next-protocol-version-unsafe-for-production,
 AM_CONDITIONAL(ENABLE_NEXT_PROTOCOL_VERSION_UNSAFE_FOR_PRODUCTION,
     [test x$enable_next_protocol_version_unsafe_for_production = xyes])
 
+AC_ARG_ENABLE(cap-0071,
+    AS_HELP_STRING([--enable-cap-0071],
+        [Enable CAP-0071 XDR types and implementation]))
+AM_CONDITIONAL(ENABLE_CAP_0071,
+    [test x$enable_cap_0071 = xyes -o x$enable_next_protocol_version_unsafe_for_production = xyes])
+
+AC_ARG_ENABLE(test-feature,
+    AS_HELP_STRING([--enable-test-feature],
+        [Enable TEST_FEATURE XDR types (testing only)]))
+AM_CONDITIONAL(ENABLE_TEST_FEATURE,
+    [test x$enable_test_feature = xyes -o x$enable_next_protocol_version_unsafe_for_production = xyes])
+
+# Derived conditional: true if any next-protocol feature is enabled.
+# Add new next-protocol feature flags to this condition.
+# Note: TEST_FEATURE is excluded as it is a test fixture, not a protocol feature.
+AM_CONDITIONAL(BUILDING_NEXT_PROTOCOL,
+    [test x$enable_next_protocol_version_unsafe_for_production = xyes -o x$enable_cap_0071 = xyes])
+
 AC_PATH_PROG(CARGO, cargo)
 if test x"$CARGO" = x; then
   AC_MSG_ERROR([cannot find cargo, needed for rust code])

hash-xdrs.sh

@@ -7,6 +7,9 @@
 #
 # The goal is to detect the (unfortunately easy) condition of C++ and Rust code
 # communicating with each other using different XDR definitions.
+#
+# Hashes are computed after stripping #ifdef/#endif blocks and removing all
+# whitespace, so they are stable regardless of feature ifdefs or formatting.
 
 set -o errexit
 set -o pipefail
@@ -28,7 +31,30 @@ EOF
 # Hashes to ignore
 IGNORE="Stellar-internal\|Stellar-overlay\|Stellar-contract-spec\|Stellar-contract-meta\|Stellar-contract-env-meta"
 
-sha256sum -b $1/xdr/*.x | grep -v "${IGNORE}" | perl -pe 's/([a-f0-9]+)[ \*]+(.*)/{"$2", "$1"},/'
+# Strip #ifdef/#endif blocks (inclusive) and remove all whitespace before
+# hashing. This produces a canonical hash of the base XDR content.
+# Content between #ifdef and #else (the feature-on branch) is stripped,
+# while content between #else and #endif (the feature-off branch) is kept,
+# since it represents the base types when no features are enabled.
+# Note: this does not hash the feature-gated XDR content. The feature flag
+# validation in checkXDRFileIdentity() separately verifies that C++ and Rust
+# have the same XDR features enabled.
+xdr_hash() {
+    awk 'BEGIN{skip=0} /#ifdef/{skip=1; next} /#else/{skip=0; next} /#endif/{skip=0; next} skip==0{print}' "$1" \
+        | tr -d '[:space:]' \
+        | sha256sum -b \
+        | cut -d' ' -f1
+}
+
+for f in $1/xdr/*.x; do
+    fname=$(basename "$f")
+    # Skip ignored files
+    if echo "$fname" | grep -q "${IGNORE}"; then
+        continue
+    fi
+    hash=$(xdr_hash "$f")
+    echo "{\"$f\", \"$hash\"},"
+done
 
 # Add empty entries for the 5 skipped files
 echo '{"", ""}, {"", ""}, {"", ""}, {"", ""}, {"", ""}};'

src/Makefile.am

@@ -62,15 +62,14 @@ CARGO_FEATURE_TESTUTILS =
 endif # !BUILD_TESTS
 
 
-if ENABLE_NEXT_PROTOCOL_VERSION_UNSAFE_FOR_PRODUCTION
+if BUILDING_NEXT_PROTOCOL
 CARGO_FEATURE_NEXT = --features next
-main/XDRFilesSha256.cpp: $(SRC_X_FILES) Makefile $(top_srcdir)/hash-xdrs.sh
-	$(top_srcdir)/hash-xdrs.sh $(top_srcdir)/src/protocol-next >$@
 else
 CARGO_FEATURE_NEXT =
+endif
+
 main/XDRFilesSha256.cpp: $(SRC_X_FILES) Makefile $(top_srcdir)/hash-xdrs.sh
 	$(top_srcdir)/hash-xdrs.sh $(top_srcdir)/src/protocol-curr >$@
-endif
 
 # tcmalloc must be linked early to properly override malloc/free
 stellar_core_LDADD = $(libtcmalloc_LIBS) $(soci_LIBS) $(libmedida_LIBS)		\
@@ -88,10 +87,18 @@ TEST_FILES = $(TESTDATA_DIR)/stellar-core_example.cfg $(TESTDATA_DIR)/stellar-co
 BUILT_SOURCES = $(SRC_X_FILES:.x=.h) main/StellarCoreVersion.cpp main/XDRFilesSha256.cpp $(TEST_FILES)
 
 $(SRC_X_FILES:.x=.h): $(XDRC)
+XDR_FEATURE_FLAGS =
+if ENABLE_CAP_0071
+XDR_FEATURE_FLAGS += -DCAP_0071
+endif
+if ENABLE_TEST_FEATURE
+XDR_FEATURE_FLAGS += -DTEST_FEATURE
+endif
+
 SUFFIXES = .x .h .rs
 .x.h:
 	mkdir -p $(@D)
-	$(XDRC) -hh -pedantic -o $@ $<
+	$(XDRC) -hh -pedantic $(XDR_FEATURE_FLAGS) -o $@ $<
 
 BISON=bison
 FLEX=flex
@@ -189,9 +196,17 @@ SOROBAN_BUILD_DIR=$(abspath $(RUST_BUILD_DIR))/soroban
 # ALL_SOROBAN_PROTOCOLS as you see fit).
 
 ALL_SOROBAN_PROTOCOLS=p21 p22 p23 p24 p25 p26
-WIP_SOROBAN_PROTOCOL=
+WIP_SOROBAN_PROTOCOL=p27
+
+CARGO_XDR_FEATURE_FLAGS =
+if ENABLE_CAP_0071
+CARGO_XDR_FEATURE_FLAGS += --features cap_0071
+endif
+if ENABLE_TEST_FEATURE
+CARGO_XDR_FEATURE_FLAGS += --features test_feature
+endif
 
-if ENABLE_NEXT_PROTOCOL_VERSION_UNSAFE_FOR_PRODUCTION
+if BUILDING_NEXT_PROTOCOL
 ALL_SOROBAN_PROTOCOLS+=$(WIP_SOROBAN_PROTOCOL)
 # This means "only pass --features=next if there's no WIP submodule"
 SOROBAN_FEATURE_NEXT=$(if $(WIP_SOROBAN_PROTOCOL),,$(CARGO_FEATURE_NEXT))
@@ -369,7 +384,7 @@ $(SOROBAN_LIBS_STAMP): $(wildcard rust/soroban/p*/Cargo.lock) $(ALL_SOROBAN_GIT_
 				FEATURE_FLAGS="" \
 			;; \
 			$(SOROBAN_MAX_PROTOCOL)) \
-				FEATURE_FLAGS="$(CARGO_FEATURE_TRACY) $(SOROBAN_FEATURE_NEXT)" \
+				FEATURE_FLAGS="$(CARGO_FEATURE_TRACY) $(SOROBAN_FEATURE_NEXT) $(CARGO_XDR_FEATURE_FLAGS)" \
 			;; \
 			*) \
 				FEATURE_FLAGS="$(CARGO_FEATURE_TRACY)" \

src/main/Config.cpp

@@ -32,7 +32,7 @@
 namespace stellar
 {
 uint32 const Config::CURRENT_LEDGER_PROTOCOL_VERSION = 26
-#ifdef ENABLE_NEXT_PROTOCOL_VERSION_UNSAFE_FOR_PRODUCTION
+#ifdef BUILDING_NEXT_PROTOCOL
                                                        + 1
 #endif
     ;