mapledan commented on code in PR #42785:
URL: https://github.com/apache/superset/pull/42785#discussion_r3963633679
##########
superset/jinja_context.py:
##########
@@ -797,6 +797,36 @@ def get_context(self) -> dict[str, Any]:
"""
return self._context.copy()
+ def has_template(self, sql: str) -> bool:
+ """Whether the SQL contains anything for ``process_template`` to expand
+
+ Lexed rather than parsed, so that a comment -- which leaves no trace in
+ a parsed template -- still counts, and using this processor's own
+ environment, so that any customized delimiters are honored. Lexing
+ evaluates nothing.
+
+ >>> has_template("SELECT '{{ current_username() }}'")
+ True
+ >>> has_template("{{ dataset(1) }}")
+ True
+ >>> has_template("SELECT '{{1,2},{3,4}}'::int[]")
+ False
+ """
+ try:
+ # The whole stream is consumed before deciding, rather than
stopping
+ # at the first non-`data` token: `'{{1,2},{3,4}}'` opens like a
+ # template and only turns out not to be one further along, where
the
+ # lexer gives up.
+ kinds = {kind for _, kind, _ in self.env.lex(sql)}
+ except TemplateSyntaxError:
+ # Jinja does not recognize this as one of its own constructs, so
+ # there is nothing here it would expand.
+ return False
+
+ # SQL that is nothing but a template produces no `data` token at all,
so
+ # this asks for any other kind rather than for `data` plus another.
+ return bool(kinds - {"data"})
Review Comment:
Good catch, and taken as stated: the contract is now explicit and the example
implements it.
`CustomPrestoTemplateProcessor` gets a `has_template` override that reports
its `$`
syntax and still defers to Jinja via `super()`. The base docstring names the
obligation and points at that module, so the next processor with its own
syntax has
somewhere to look. There is a test both ways — the custom processor reports
`$DATE(...)` as a template, and the base processor reports the same SQL as
having
none, which is what makes the override necessary.
One thing worth flagging that falls out of the first thread: because the
render gate
is gone, `process_template` is now always called, so that processor does get
to
expand `$DATE(...)` on the estimate path. The old gate skipped it whenever
`template_params` was empty, and master still does.
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