From 390d58135b22bc25229b524a60f69682182201d8 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Sat, 9 Dec 2017 12:03:00 -0500 Subject: [PATCH] Fix plpgsql to reinitialize record variables at block re-entry. If one exits and re-enters a DECLARE ... BEGIN ... END block within a single execution of a plpgsql function, perhaps due to a surrounding loop, the declared variables are supposed to get re-initialized to null (or whatever their initializer is). But this failed to happen for variables of type "record", because while exec_stmt_block() expected such variables to be included in the block's initvarnos list, plpgsql_add_initdatums() only adds DTYPE_VAR variables to that list. This bug appears to have been there since the aboriginal addition of plpgsql to our tree. Fix by teaching plpgsql_add_initdatums() to include DTYPE_REC variables as well. (We don't need to consider other DTYPEs because they don't represent separately-stored values.) I failed to resist the temptation to make some nearby cosmetic adjustments, too. No back-patch, because there have not been field complaints, and it seems possible that somewhere out there someone has code depending on the incorrect behavior. In any case this change would have no impact on correctly-written code. Discussion: https://postgr.es/m/22994.1512800671@sss.pgh.pa.us --- src/pl/plpgsql/src/pl_comp.c | 12 +++++++++--- src/pl/plpgsql/src/pl_exec.c | 20 +++++++++----------- src/pl/plpgsql/src/plpgsql.h | 4 ++-- src/test/regress/expected/plpgsql.out | 27 +++++++++++++++++++++++++++ src/test/regress/sql/plpgsql.sql | 21 +++++++++++++++++++++ 5 files changed, 68 insertions(+), 16 deletions(-) diff --git a/src/pl/plpgsql/src/pl_comp.c b/src/pl/plpgsql/src/pl_comp.c index 1300ea6a52..2d7844bd9d 100644 --- a/src/pl/plpgsql/src/pl_comp.c +++ b/src/pl/plpgsql/src/pl_comp.c @@ -2384,14 +2384,14 @@ plpgsql_finish_datums(PLpgSQL_function *function) /* ---------- * plpgsql_add_initdatums Make an array of the datum numbers of - * all the simple VAR datums created since the last call + * all the initializable datums created since the last call * to this function. * * If varnos is NULL, we just forget any datum entries created since the * last call. * - * This is used around a DECLARE section to create a list of the VARs - * that have to be initialized at block entry. Note that VARs can also + * This is used around a DECLARE section to create a list of the datums + * that have to be initialized at block entry. Note that datums can also * be created elsewhere than DECLARE, eg by a FOR-loop, but it is then * the responsibility of special-purpose code to initialize them. * ---------- @@ -2402,11 +2402,16 @@ plpgsql_add_initdatums(int **varnos) int i; int n = 0; + /* + * The set of dtypes recognized here must match what exec_stmt_block() + * cares about (re)initializing at block entry. + */ for (i = datums_last; i < plpgsql_nDatums; i++) { switch (plpgsql_Datums[i]->dtype) { case PLPGSQL_DTYPE_VAR: + case PLPGSQL_DTYPE_REC: n++; break; @@ -2427,6 +2432,7 @@ plpgsql_add_initdatums(int **varnos) switch (plpgsql_Datums[i]->dtype) { case PLPGSQL_DTYPE_VAR: + case PLPGSQL_DTYPE_REC: (*varnos)[n++] = plpgsql_Datums[i]->dno; default: diff --git a/src/pl/plpgsql/src/pl_exec.c b/src/pl/plpgsql/src/pl_exec.c index 1959d6dc42..fa4d573e50 100644 --- a/src/pl/plpgsql/src/pl_exec.c +++ b/src/pl/plpgsql/src/pl_exec.c @@ -1184,7 +1184,6 @@ exec_stmt_block(PLpgSQL_execstate *estate, PLpgSQL_stmt_block *block) { volatile int rc = -1; int i; - int n; /* * First initialize all variables declared in this block @@ -1193,13 +1192,17 @@ exec_stmt_block(PLpgSQL_execstate *estate, PLpgSQL_stmt_block *block) for (i = 0; i < block->n_initvars; i++) { - n = block->initvarnos[i]; + int n = block->initvarnos[i]; + PLpgSQL_datum *datum = estate->datums[n]; - switch (estate->datums[n]->dtype) + /* + * The set of dtypes handled here must match plpgsql_add_initdatums(). + */ + switch (datum->dtype) { case PLPGSQL_DTYPE_VAR: { - PLpgSQL_var *var = (PLpgSQL_var *) (estate->datums[n]); + PLpgSQL_var *var = (PLpgSQL_var *) datum; /* * Free any old value, in case re-entering block, and @@ -1241,7 +1244,7 @@ exec_stmt_block(PLpgSQL_execstate *estate, PLpgSQL_stmt_block *block) case PLPGSQL_DTYPE_REC: { - PLpgSQL_rec *rec = (PLpgSQL_rec *) (estate->datums[n]); + PLpgSQL_rec *rec = (PLpgSQL_rec *) datum; if (rec->freetup) { @@ -1258,13 +1261,8 @@ exec_stmt_block(PLpgSQL_execstate *estate, PLpgSQL_stmt_block *block) } break; - case PLPGSQL_DTYPE_RECFIELD: - case PLPGSQL_DTYPE_ARRAYELEM: - break; - default: - elog(ERROR, "unrecognized dtype: %d", - estate->datums[n]->dtype); + elog(ERROR, "unrecognized dtype: %d", datum->dtype); } } diff --git a/src/pl/plpgsql/src/plpgsql.h b/src/pl/plpgsql/src/plpgsql.h index 8448578537..39bd82acd1 100644 --- a/src/pl/plpgsql/src/plpgsql.h +++ b/src/pl/plpgsql/src/plpgsql.h @@ -407,8 +407,8 @@ typedef struct PLpgSQL_stmt_block int lineno; char *label; List *body; /* List of statements */ - int n_initvars; - int *initvarnos; + int n_initvars; /* Length of initvarnos[] */ + int *initvarnos; /* dnos of variables declared in this block */ PLpgSQL_exception_block *exceptions; } PLpgSQL_stmt_block; diff --git a/src/test/regress/expected/plpgsql.out b/src/test/regress/expected/plpgsql.out index d6e5bc3353..29f9e86d56 100644 --- a/src/test/regress/expected/plpgsql.out +++ b/src/test/regress/expected/plpgsql.out @@ -5025,6 +5025,33 @@ select scope_test(); (1 row) drop function scope_test(); +-- Check that variables are reinitialized on block re-entry. +do $$ +begin + for i in 1..3 loop + declare + x int; + y int := i; + r record; + begin + if i = 1 then + x := 42; + r := row(i, i+1); + end if; + raise notice 'x = %', x; + raise notice 'y = %', y; + raise notice 'r = %', r; + end; + end loop; +end$$; +NOTICE: x = 42 +NOTICE: y = 1 +NOTICE: r = (1,2) +NOTICE: x = +NOTICE: y = 2 +ERROR: record "r" is not assigned yet +DETAIL: The tuple structure of a not-yet-assigned record is indeterminate. +CONTEXT: PL/pgSQL function inline_code_block line 15 at RAISE -- Check handling of conflicts between plpgsql vars and table columns. set plpgsql.variable_conflict = error; create function conflict_test() returns setof int8_tbl as $$ diff --git a/src/test/regress/sql/plpgsql.sql b/src/test/regress/sql/plpgsql.sql index 1c355132b7..07b6fc8971 100644 --- a/src/test/regress/sql/plpgsql.sql +++ b/src/test/regress/sql/plpgsql.sql @@ -4014,6 +4014,27 @@ select scope_test(); drop function scope_test(); +-- Check that variables are reinitialized on block re-entry. + +do $$ +begin + for i in 1..3 loop + declare + x int; + y int := i; + r record; + begin + if i = 1 then + x := 42; + r := row(i, i+1); + end if; + raise notice 'x = %', x; + raise notice 'y = %', y; + raise notice 'r = %', r; + end; + end loop; +end$$; + -- Check handling of conflicts between plpgsql vars and table columns. set plpgsql.variable_conflict = error; -- 2.40.0