Remove distprep

A PostgreSQL release tarball contains a number of prebuilt files, in
particular files produced by bison, flex, perl, and well as html and
man documentation.  We have done this consistent with established
practice at the time to not require these tools for building from a
tarball.  Some of these tools were hard to get, or get the right
version of, from time to time, and shipping the prebuilt output was a
convenience to users.

Now this has at least two problems:

One, we have to make the build system(s) work in two modes: Building
from a git checkout and building from a tarball.  This is pretty
complicated, but it works so far for autoconf/make.  It does not
currently work for meson; you can currently only build with meson from
a git checkout.  Making meson builds work from a tarball seems very
difficult or impossible.  One particular problem is that since meson
requires a separate build directory, we cannot make the build update
files like gram.h in the source tree.  So if you were to build from a
tarball and update gram.y, you will have a gram.h in the source tree
and one in the build tree, but the way things work is that the
compiler will always use the one in the source tree.  So you cannot,
for example, make any gram.y changes when building from a tarball.
This seems impossible to fix in a non-horrible way.

Second, there is increased interest nowadays in precisely tracking the
origin of software.  We can reasonably track contributions into the
git tree, and users can reasonably track the path from a tarball to
packages and downloads and installs.  But what happens between the git
tree and the tarball is obscure and in some cases non-reproducible.

The solution for both of these issues is to get rid of the step that
adds prebuilt files to the tarball.  The tarball now only contains
what is in the git tree (*).  Getting the additional build
dependencies is no longer a problem nowadays, and the complications to
keep these dual build modes working are significant.  And of course we
want to get the meson build system working universally.

This commit removes the make distprep target altogether.  The make
dist target continues to do its job, it just doesn't call distprep
anymore.

(*) - The tarball also contains the INSTALL file that is built at make
dist time, but not by distprep.  This is unchanged for now.

The make maintainer-clean target, whose job it is to remove the
prebuilt files in addition to what make distclean does, is now just an
alias to make distprep.  (In practice, it is probably obsolete given
that git clean is available.)

The following programs are now hard build requirements in configure
(they were already required by meson.build):

- bison
- flex
- perl

Reviewed-by: Michael Paquier <michael@paquier.xyz>
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://www.postgresql.org/message-id/flat/e07408d9-e5f2-d9fd-5672-f53354e9305e@eisentraut.org

4 files changed, 42 insertions, 69 deletions

diff --git a/doc/src/Makefile b/doc/src/Makefile
index 30d883815aa..2ed02084ff5 100644
--- a/doc/src/Makefile
+++ b/doc/src/Makefile
@@ -4,5 +4,5 @@ subdir = doc/src
 top_builddir = ../..
 include $(top_builddir)/src/Makefile.global
 
-all distprep html man install installdirs uninstall clean distclean maintainer-clean:
+all html man install installdirs uninstall clean distclean:
 	$(MAKE) -C sgml $@
diff --git a/doc/src/sgml/Makefile b/doc/src/sgml/Makefile
index 1e55e531dbf..49d35dd0d6e 100644
--- a/doc/src/sgml/Makefile
+++ b/doc/src/sgml/Makefile
@@ -7,8 +7,7 @@
 #----------------------------------------------------------------------------
 
 # This makefile is for building and installing the documentation.
-# When a release tarball is created, the documentation files are
-# prepared using the distprep target.  In Git-based trees these files
+# In Git-based trees these files
 # don't exist, unless explicitly built, so we skip the installation in
 # that case.
 
@@ -28,8 +27,6 @@ include $(top_builddir)/src/Makefile.global
 
 all: html man
 
-distprep: html distprep-man
-
 
 ifndef DBTOEPUB
 DBTOEPUB = $(missing) dbtoepub
@@ -77,7 +74,7 @@ postgres-full.xml: postgres.sgml $(ALLSGML)
 ## Man pages
 ##
 
-man distprep-man: man-stamp
+man: man-stamp
 
 man-stamp: stylesheet-man.xsl postgres-full.xml
 	$(XSLTPROC) $(XMLINCLUDE) $(XSLTPROCFLAGS) $(XSLTPROC_MAN_FLAGS) $^
@@ -89,10 +86,9 @@ man-stamp: stylesheet-man.xsl postgres-full.xml
 ##
 
 # Technically, this should depend on Makefile.global, but then
-# version.sgml would need to be rebuilt after every configure run,
-# even in distribution tarballs.  So this is cheating a bit, but it
-# will achieve the goal of updating the version number when it
-# changes.
+# version.sgml would need to be rebuilt after every configure run.  So
+# this is cheating a bit, but it will achieve the goal of updating the
+# version number when it changes.
 version.sgml: $(top_srcdir)/configure
 	{ \
 	  echo "<!ENTITY version \"$(VERSION)\">"; \
@@ -305,8 +301,6 @@ clean:
 	rm -f *.texixml *.texi *.info db2texi.refs
 
 distclean: clean
-
-maintainer-clean: distclean
 # HTML
 	rm -fr html/ html-stamp
 # man
diff --git a/doc/src/sgml/installation.sgml b/doc/src/sgml/installation.sgml
index 9b25e9fdb1b..a3dc6eb855f 100644
--- a/doc/src/sgml/installation.sgml
+++ b/doc/src/sgml/installation.sgml
@@ -72,8 +72,7 @@ documentation.  See standalone-profile.xsl for details.
 
       Alternatively, <productname>PostgreSQL</productname> can be built using
       <ulink url="https://mesonbuild.com/">Meson</ulink>.  This is currently
-      experimental and only works when building from a Git checkout (not from
-      a distribution tarball).  If you choose to use
+      experimental.  If you choose to use
       <application>Meson</application>, then you don't need
       <acronym>GNU</acronym> <application>make</application>, but the other
       requirements below still apply.
@@ -105,6 +104,41 @@ documentation.  See standalone-profile.xsl for details.
     <listitem>
      <para>
       <indexterm>
+       <primary>flex</primary>
+      </indexterm>
+      <indexterm>
+       <primary>lex</primary>
+      </indexterm>
+      <indexterm>
+       <primary>bison</primary>
+      </indexterm>
+      <indexterm>
+       <primary>yacc</primary>
+      </indexterm>
+
+      <application>Flex</application> 2.5.35 or later and
+      <application>Bison</application> 2.3 or later are required.  Other
+      <application>lex</application> and <application>yacc</application>
+      programs cannot be used.
+     </para>
+    </listitem>
+
+    <listitem>
+     <para>
+      <indexterm>
+       <primary>perl</primary>
+      </indexterm>
+
+      <application>Perl</application> 5.14 or later is needed during the build
+      process and to run some test suites.  (This requirement is separate from
+      the requirements for building <application>PL/Perl</application>; see
+      below.)
+     </para>
+    </listitem>
+
+    <listitem>
+     <para>
+      <indexterm>
        <primary>readline</primary>
       </indexterm>
       <indexterm>
@@ -316,51 +350,6 @@ documentation.  See standalone-profile.xsl for details.
   </para>
 
   <para>
-   If you are building from a <productname>Git</productname> tree instead of
-   using a released source package, or if you want to do server development,
-   you also need the following packages:
-
-   <itemizedlist>
-    <listitem>
-     <para>
-      <indexterm>
-       <primary>flex</primary>
-      </indexterm>
-      <indexterm>
-       <primary>lex</primary>
-      </indexterm>
-      <indexterm>
-       <primary>bison</primary>
-      </indexterm>
-      <indexterm>
-       <primary>yacc</primary>
-      </indexterm>
-
-      <application>Flex</application> and <application>Bison</application>
-      are needed to build from a Git checkout, or if you changed the actual
-      scanner and parser definition files. If you need them, be sure
-      to get <application>Flex</application> 2.5.35 or later and
-      <application>Bison</application> 2.3 or later. Other <application>lex</application>
-      and <application>yacc</application> programs cannot be used.
-     </para>
-    </listitem>
-    <listitem>
-     <para>
-      <indexterm>
-       <primary>perl</primary>
-      </indexterm>
-
-      <application>Perl</application> 5.14 or later is needed to build from a Git checkout,
-      or if you changed the input files for any of the build steps that
-      use Perl scripts.  If building on Windows you will need
-      <application>Perl</application> in any case.  <application>Perl</application> is
-      also required to run some test suites.
-     </para>
-    </listitem>
-   </itemizedlist>
-  </para>
-
-  <para>
    If you need to get a <acronym>GNU</acronym> package, you can find
    it at your local <acronym>GNU</acronym> mirror site (see <ulink
    url="https://www.gnu.org/prep/ftp"></ulink>
diff --git a/doc/src/sgml/sourcerepo.sgml b/doc/src/sgml/sourcerepo.sgml
index 07b003a7941..6c13c5a30cd 100644
--- a/doc/src/sgml/sourcerepo.sgml
+++ b/doc/src/sgml/sourcerepo.sgml
@@ -16,16 +16,6 @@
   has some discussion on working with Git.
  </para>
 
-  <para>
-   Note that building <productname>PostgreSQL</productname> from the source
-   repository requires reasonably up-to-date versions of <application>bison</application>,
-   <application>flex</application>, and <application>Perl</application>.
-   These tools are not needed to build from a distribution tarball, because
-   the files generated with these tools are included in the tarball.
-   Other tool requirements
-   are the same as shown in <xref linkend="install-requirements"/>.
-  </para>
-
  <sect1 id="git">
   <title>Getting the Source via <productname>Git</productname></title>