Remove dynamic translation of regression test scripts, step 1.

pg_regress has long had provisions for dynamically substituting path
names into regression test scripts and result files, but use of that
feature has always been a serious pain in the neck, mainly because
updating the result files requires tedious manual editing.  Let's
get rid of that in favor of passing down the paths in environment
variables.

In addition to being easier to maintain, this way is capable of
dealing with path names that require escaping at runtime, for example
paths containing single-quote marks.  (There are other stumbling
blocks in the way of actually building in a path that looks like
that, but removing this one seems like a good thing to do.)  The key
coding rule that makes that possible is to concatenate pieces of a
dynamically-variable string using psql's \set command, and then use
the :'variable' notation to quote and escape the string for the next
level of interpretation.

In hopes of making this change more transparent to "git blame",
I've split it into two steps.  This commit adds the necessary
pg_regress.c support and changes all the *.source files in-place
so that they no longer require any dynamic translation.  The next
commit will just "git mv" them into the regular sql/ and expected/
directories.

Discussion: https://postgr.es/m/1655733.1639871614@sss.pgh.pa.us

2 files changed, 39 insertions, 50 deletions

diff --git a/src/pl/plpgsql/src/input/plpgsql_copy.source b/src/pl/plpgsql/src/input/plpgsql_copy.source
index b7bcbb7d17f..37f1fa132b2 100644
--- a/src/pl/plpgsql/src/input/plpgsql_copy.source
+++ b/src/pl/plpgsql/src/input/plpgsql_copy.source
@@ -1,3 +1,11 @@
+-- directory paths are passed to us in environment variables
+\getenv abs_srcdir PG_ABS_SRCDIR
+\getenv abs_builddir PG_ABS_BUILDDIR
+
+-- set up file names to use
+\set srcfilename :abs_srcdir '/data/copy1.data'
+\set destfilename :abs_builddir '/results/copy1.data'
+
 CREATE TABLE copy1 (a int, b float);
 
 -- COPY TO/FROM not authorized from client.
@@ -24,38 +32,26 @@ $$;
 
 -- Valid cases
 -- COPY FROM
-DO LANGUAGE plpgsql $$
-BEGIN
-  COPY copy1 FROM '@abs_srcdir@/data/copy1.data';
-END;
-$$;
+\set dobody 'BEGIN COPY copy1 FROM ' :'srcfilename' '; END'
+DO LANGUAGE plpgsql :'dobody';
 SELECT * FROM copy1 ORDER BY 1;
 TRUNCATE copy1;
-DO LANGUAGE plpgsql $$
-BEGIN
-  EXECUTE 'COPY copy1 FROM ''@abs_srcdir@/data/copy1.data''';
-END;
-$$;
+\set cmd 'COPY copy1 FROM ' :'srcfilename'
+\set dobody 'BEGIN EXECUTE ' :'cmd' '; END'
+DO LANGUAGE plpgsql :'dobody';
 SELECT * FROM copy1 ORDER BY 1;
 
 -- COPY TO
 -- Copy the data externally once, then process it back to the table.
-DO LANGUAGE plpgsql $$
-BEGIN
-  COPY copy1 TO '@abs_builddir@/results/copy1.data';
-END;
-$$;
+\set dobody 'BEGIN COPY copy1 TO ' :'destfilename' '; END'
+DO LANGUAGE plpgsql :'dobody';
 TRUNCATE copy1;
-DO LANGUAGE plpgsql $$
-BEGIN
-  COPY copy1 FROM '@abs_builddir@/results/copy1.data';
-END;
-$$;
-DO LANGUAGE plpgsql $$
-BEGIN
-  EXECUTE 'COPY copy1 FROM ''@abs_builddir@/results/copy1.data''';
-END;
-$$;
+\set dobody 'BEGIN COPY copy1 FROM ' :'destfilename' '; END'
+DO LANGUAGE plpgsql :'dobody';
+
+\set cmd 'COPY copy1 FROM ' :'destfilename'
+\set dobody 'BEGIN EXECUTE ' :'cmd' '; END'
+DO LANGUAGE plpgsql :'dobody';
 
 SELECT * FROM copy1 ORDER BY 1;
 
diff --git a/src/pl/plpgsql/src/output/plpgsql_copy.source b/src/pl/plpgsql/src/output/plpgsql_copy.source
index 86e833d055a..bc834be1971 100644
--- a/src/pl/plpgsql/src/output/plpgsql_copy.source
+++ b/src/pl/plpgsql/src/output/plpgsql_copy.source
@@ -1,3 +1,9 @@
+-- directory paths are passed to us in environment variables
+\getenv abs_srcdir PG_ABS_SRCDIR
+\getenv abs_builddir PG_ABS_BUILDDIR
+-- set up file names to use
+\set srcfilename :abs_srcdir '/data/copy1.data'
+\set destfilename :abs_builddir '/results/copy1.data'
 CREATE TABLE copy1 (a int, b float);
 -- COPY TO/FROM not authorized from client.
 DO LANGUAGE plpgsql $$
@@ -30,11 +36,8 @@ ERROR:  cannot COPY to/from client in PL/pgSQL
 CONTEXT:  PL/pgSQL function inline_code_block line 3 at EXECUTE
 -- Valid cases
 -- COPY FROM
-DO LANGUAGE plpgsql $$
-BEGIN
-  COPY copy1 FROM '@abs_srcdir@/data/copy1.data';
-END;
-$$;
+\set dobody 'BEGIN COPY copy1 FROM ' :'srcfilename' '; END'
+DO LANGUAGE plpgsql :'dobody';
 SELECT * FROM copy1 ORDER BY 1;
  a |  b  
 ---+-----
@@ -44,11 +47,9 @@ SELECT * FROM copy1 ORDER BY 1;
 (3 rows)
 
 TRUNCATE copy1;
-DO LANGUAGE plpgsql $$
-BEGIN
-  EXECUTE 'COPY copy1 FROM ''@abs_srcdir@/data/copy1.data''';
-END;
-$$;
+\set cmd 'COPY copy1 FROM ' :'srcfilename'
+\set dobody 'BEGIN EXECUTE ' :'cmd' '; END'
+DO LANGUAGE plpgsql :'dobody';
 SELECT * FROM copy1 ORDER BY 1;
  a |  b  
 ---+-----
@@ -59,22 +60,14 @@ SELECT * FROM copy1 ORDER BY 1;
 
 -- COPY TO
 -- Copy the data externally once, then process it back to the table.
-DO LANGUAGE plpgsql $$
-BEGIN
-  COPY copy1 TO '@abs_builddir@/results/copy1.data';
-END;
-$$;
+\set dobody 'BEGIN COPY copy1 TO ' :'destfilename' '; END'
+DO LANGUAGE plpgsql :'dobody';
 TRUNCATE copy1;
-DO LANGUAGE plpgsql $$
-BEGIN
-  COPY copy1 FROM '@abs_builddir@/results/copy1.data';
-END;
-$$;
-DO LANGUAGE plpgsql $$
-BEGIN
-  EXECUTE 'COPY copy1 FROM ''@abs_builddir@/results/copy1.data''';
-END;
-$$;
+\set dobody 'BEGIN COPY copy1 FROM ' :'destfilename' '; END'
+DO LANGUAGE plpgsql :'dobody';
+\set cmd 'COPY copy1 FROM ' :'destfilename'
+\set dobody 'BEGIN EXECUTE ' :'cmd' '; END'
+DO LANGUAGE plpgsql :'dobody';
 SELECT * FROM copy1 ORDER BY 1;
  a |  b  
 ---+-----