jlink: Hash of module differs to expected hash recorded in java.base

Bug-Debian: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=944738
Forwarded: not-needed

The cause is the use of dh_strip_nondeterminism late in the build
process.  This reorganises the jmod files, which in turn changes their
SHA256 checksums.  This would not be a problem, except that the
checksums are saved in java.base.jmod *before* the use of
dh_strip_nondeterminism.  Performing this stripping immediately after
each jmod file is created results in the checksums being consistent
throughout.

Gbp-Pq: Name reproducible-build-jmod.diff

diff --git a/make/CreateJmods.gmk b/make/CreateJmods.gmk
index e1f18459071c63c60b041ab8d8dbf6242686628b..4fd9294e66444a9b493e0950fc8f7226ee07f307 100644 (file)
--- a/make/CreateJmods.gmk
+++ b/make/CreateJmods.gmk
@@ -230,6 +230,15 @@ endif
 
 # Create jmods in the support dir and then move them into place to keep the
 # module path in $(IMAGES_OUTPUTDIR)/jmods valid at all times.
+# strip-nondeterminism requires the same timestamp as
+# dh_strip_nondeterminism uses, so we determine this first.
+# Fall back to the original behavior if the tools are missing for backports
+DSN_TIMESTAMP := $(shell perl -MDebian::Debhelper::Dh_Lib -e 'print get_source_date_epoch()' 2>/dev/null)
+ifneq (,$(DSN_TIMESTAMP))
+  ifneq (,$(wildcard /bin/strip-nondeterminism /usr/bin/strip-nondeterminism))
+    use_strip_ndt = yes
+  endif
+endif
 $(eval $(call SetupExecute, create_$(JMOD_FILE), \
     WARN := Creating $(INTERIM_MSG)$(JMOD_FILE), \
     DEPS := $(DEPS), \
@@ -241,7 +250,7 @@ $(eval $(call SetupExecute, create_$(JMOD_FILE), \
         --module-path $(JMODS_DIR) $(JMOD_FLAGS) \
         $(JMOD_SOURCE_DATE) \
         $(JMODS_SUPPORT_DIR)/$(JMOD_FILE), \
-    POST_COMMAND := $(MV) $(JMODS_SUPPORT_DIR)/$(JMOD_FILE) $(JMODS_DIR)/$(JMOD_FILE), \
+    POST_COMMAND := $(if $(use_strip_ndt),strip-nondeterminism --timestamp $(DSN_TIMESTAMP) $(JMODS_SUPPORT_DIR)/$(JMOD_FILE) && )$(MV) $(JMODS_SUPPORT_DIR)/$(JMOD_FILE) $(JMODS_DIR)/$(JMOD_FILE), \
 ))
 
 TARGETS += $(create_$(JMOD_FILE))