Bug#863015: jellyfish: please make the output reproducible

[Chris Lamb]

Source: jellyfish
Version: 2.2.6-1
Severity: wishlist
Tags: patch
User: reproducible-bui...@lists.alioth.debian.org
Usertags: timestamps toolchain buildpath
X-Debbugs-Cc: reproducible-b...@lists.alioth.debian.org

Hi,

Whilst working on the Reproducible Builds effort [0], we noticed
that jellyfish generated JSON files that are not reproducible.

This is due to including the output of getcwd(3) and the current date
in the local timezone. It affects other packages in the archive (eg.
src:quorum).

Patch attached.

 [0] https://reproducible-builds.org/


Regards,

-- 
      ,''`.
     : :'  :     Chris Lamb
     `. `'`      la...@debian.org / chris-lamb.co.uk
       `-

diff --git a/include/jellyfish/generic_file_header.hpp 
b/include/jellyfish/generic_file_header.hpp
index a8ddf82..99f80b2 100644
--- a/include/jellyfish/generic_file_header.hpp
+++ b/include/jellyfish/generic_file_header.hpp
@@ -180,6 +180,8 @@ public:
 
 protected:
   std::string get_hostname() const {
+    if(std::getenv("SOURCE_DATE_EPOCH"))
+      return "";
     struct utsname buf;
     if(uname(&buf) == -1)
       return "";
@@ -187,6 +189,8 @@ protected:
   }
 
   std::string get_pwd() const {
+    if(std::getenv("SOURCE_DATE_EPOCH"))
+      return ".";
 #ifdef PATH_MAX
     size_t len = PATH_MAX;
 #else
@@ -202,6 +206,16 @@ protected:
   std::string get_localtime() const {
     time_t t = time(0);
     std::string res(ctime(&t));
+    char *source_date_epoch = std::getenv("SOURCE_DATE_EPOCH");
+    if(source_date_epoch) {
+      std::istringstream iss(source_date_epoch);
+      iss >> t;
+      if(iss.fail() || !iss.eof()) {
+        std::cerr << "Error: Cannot parse SOURCE_DATE_EPOCH as integer\n";
+        exit(27);
+      }
+      res = asctime(gmtime(&t));
+    }
     chomp(res);
     return res;
   }