From 01df14763431df1506cbae206945cd165c66d1d3 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Fri, 3 May 2024 11:08:50 -0400
Subject: [PATCH] Allow selecting the git revision to be packaged by "make
 dist".

Commit 619bc23a1 changed "make dist" to invoke "git archive",
but hard-wired the call to specify that the HEAD revision should
be packaged.  Our tarball building process needs to be able to
specify which git commit to package (notably, for packaging
back branches).  While we could make that work with some hackery
to operate in detached-HEAD state, it's a lot nicer just to expose
git archive's ability to specify what to package.  Hence, invent
a new make variable PG_GIT_REVISION.  This is undocumented, but
so is "make dist".

Also make corresponding changes in the meson scripts.  We have no
near-term intention of using that for package building, but it
will likely happen eventually, so stay prepared.

Discussion: https://postgr.es/m/3552543.1713909947@sss.pgh.pa.us
---
 GNUmakefile.in    | 7 +++++--
 meson.build       | 6 ++++--
 meson_options.txt | 3 +++
 3 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/GNUmakefile.in b/GNUmakefile.in
index 30553b2a95..cf6e759486 100644
--- a/GNUmakefile.in
+++ b/GNUmakefile.in
@@ -87,6 +87,9 @@ update-unicode: | submake-generated-headers submake-libpgport
 distdir	= postgresql-$(VERSION)
 dummy	= =install=
 
+# git revision to be packaged
+PG_GIT_REVISION = HEAD
+
 GIT = git
 
 dist: $(distdir).tar.gz $(distdir).tar.bz2
@@ -102,10 +105,10 @@ distdir-location:
 # on, Unix machines.
 
 $(distdir).tar.gz:
-	$(GIT) -C $(srcdir) -c core.autocrlf=false archive --format tar.gz -9 --prefix $(distdir)/ HEAD -o $(abs_top_builddir)/$@
+	$(GIT) -C $(srcdir) -c core.autocrlf=false archive --format tar.gz -9 --prefix $(distdir)/ $(PG_GIT_REVISION) -o $(abs_top_builddir)/$@
 
 $(distdir).tar.bz2:
-	$(GIT) -C $(srcdir) -c core.autocrlf=false -c tar.tar.bz2.command='$(BZIP2) -c' archive --format tar.bz2 --prefix $(distdir)/ HEAD -o $(abs_top_builddir)/$@
+	$(GIT) -C $(srcdir) -c core.autocrlf=false -c tar.tar.bz2.command='$(BZIP2) -c' archive --format tar.bz2 --prefix $(distdir)/ $(PG_GIT_REVISION) -o $(abs_top_builddir)/$@
 
 distcheck: dist
 	rm -rf $(dummy)
diff --git a/meson.build b/meson.build
index cdfd31377d..1c0579d5a6 100644
--- a/meson.build
+++ b/meson.build
@@ -3469,6 +3469,8 @@ bzip2 = find_program('bzip2', required: false, native: true)
 
 distdir = meson.project_name() + '-' + meson.project_version()
 
+pg_git_revision = get_option('PG_GIT_REVISION')
+
 # Note: core.autocrlf=false is needed to avoid line-ending conversion
 # in case the environment has a different setting.  Without this, a
 # tarball created on Windows might be different than on, and unusable
@@ -3483,7 +3485,7 @@ tar_gz = custom_target('tar.gz',
             '-9',
             '--prefix', distdir + '/',
             '-o', join_paths(meson.build_root(), '@OUTPUT@'),
-            'HEAD', '.'],
+            pg_git_revision],
   output: distdir + '.tar.gz',
 )
 
@@ -3497,7 +3499,7 @@ if bzip2.found()
               '--format', 'tar.bz2',
               '--prefix', distdir + '/',
               '-o', join_paths(meson.build_root(), '@OUTPUT@'),
-              'HEAD', '.'],
+              pg_git_revision],
     output: distdir + '.tar.bz2',
   )
 else
diff --git a/meson_options.txt b/meson_options.txt
index 249ecc5ffd..246cecf382 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -55,6 +55,9 @@ option('atomics', type: 'boolean', value: true,
 option('spinlocks', type: 'boolean', value: true,
   description: 'Use spinlocks')
 
+option('PG_GIT_REVISION', type: 'string', value: 'HEAD',
+  description: 'git revision to be packaged by pgdist target')
+
 
 # Compilation options