Auto-generate the release date on version.h from git CommitDate (#6382)

* Auto-generate the release date on version.h

from git CommitDate

* Generate revision.h on mswin

3 files changed, 27 insertions, 7 deletions

diff --git a/tool/file2lastrev.rb b/tool/file2lastrev.rb
index 008e4b55e5..476437a995 100755
--- a/tool/file2lastrev.rb
+++ b/tool/file2lastrev.rb
@@ -66,7 +66,13 @@ OptionParser.new {|opts|
     new_vcs["."]
   end
 }
-exit unless vcs
+unless vcs
+  # Output only release_date when .git is missing
+  if @output == :revision_h
+    puts VCS.release_date(Time.now - 10) # same as make-snapshot
+  end
+  exit
+end
 
 @output =
   case @output
@@ -76,7 +82,7 @@ exit unless vcs
     }
   when :revision_h
     Proc.new {|last, changed, modified, branch, title|
-      vcs.revision_header(last, modified, branch, title, limit: @limit)
+      vcs.revision_header(last, modified, modified, branch, title, limit: @limit)
     }
   when :doxygen
     Proc.new {|last, changed|
diff --git a/tool/lib/vcs.rb b/tool/lib/vcs.rb
index 05d95061c4..d33d41dba1 100644
--- a/tool/lib/vcs.rb
+++ b/tool/lib/vcs.rb
@@ -95,6 +95,15 @@ class VCS
     opts
   end
 
+  def self.release_date(time)
+    t = time.utc
+    [
+      t.strftime('#define RUBY_RELEASE_YEAR %Y'),
+      t.strftime('#define RUBY_RELEASE_MONTH %-m'),
+      t.strftime('#define RUBY_RELEASE_DAY %-d'),
+    ]
+  end
+
   attr_reader :srcdir
 
   def initialize(path)
@@ -204,7 +213,8 @@ class VCS
     revision_handler(rev).short_revision(rev)
   end
 
-  def revision_header(last, modified = nil, branch = nil, title = nil, limit: 20)
+  # make-snapshot generates only release_date whereas file2lastrev generates both release_date and release_datetime
+  def revision_header(last, release_date, release_datetime = nil, branch = nil, title = nil, limit: 20)
     short = short_revision(last)
     if /[^\x00-\x7f]/ =~ title and title.respond_to?(:force_encoding)
       title = title.dup.force_encoding("US-ASCII")
@@ -225,10 +235,11 @@ class VCS
       title = title.dump.sub(/\\#/, '#')
       code << "#define RUBY_LAST_COMMIT_TITLE #{title}"
     end
-    if modified
-      t = modified.utc
+    if release_datetime
+      t = release_datetime.utc
       code << t.strftime('#define RUBY_RELEASE_DATETIME "%FT%TZ"')
     end
+    code += VCS.release_date(release_date)
     code
   end
 
@@ -386,7 +397,10 @@ class VCS
   end
 
   class GIT < self
-    register(".git") {|path, dir| File.exist?(File.join(path, dir))}
+    register(".git") do |path, dir|
+      File.exist?(File.join(path, dir)) &&
+        (`#{COMMAND} -v` rescue false) # make sure git command exists
+    end
     COMMAND = ENV["GIT"] || 'git'
 
     def cmd_args(cmds, srcdir = nil)
diff --git a/tool/make-snapshot b/tool/make-snapshot
index 02b5d182f5..22ae360c3e 100755
--- a/tool/make-snapshot
+++ b/tool/make-snapshot
@@ -347,7 +347,7 @@ def package(vcs, rev, destdir, tmp = nil)
   end
 
   File.open("#{v}/revision.h", "wb") {|f|
-    f.puts vcs.revision_header(revision)
+    f.puts vcs.revision_header(revision, modified)
   }
   version ||= (versionhdr = IO.read("#{v}/version.h"))[RUBY_VERSION_PATTERN, 1]
   version ||=