From 936744dfd6054d986ea784bd1e4acc4472684992 Mon Sep 17 00:00:00 2001
From: Jesse Wang <jesse@wang.nz>
Date: Fri, 15 Mar 2024 08:05:44 +1300
Subject: [PATCH] Fix describe on PostgreSQL views with rules (#2736)

* fix postgres describe on multiple explains

* inline the first explain using smallvec

* fix: regenerate `Cargo.lock`

---------

Co-authored-by: Austin Bonander <austin.bonander@gmail.com>
---
 Cargo.lock                               | 19 +++++++++++--------
 sqlx-postgres/Cargo.toml                 |  2 +-
 sqlx-postgres/src/connection/describe.rs | 10 ++++++----
 3 files changed, 18 insertions(+), 13 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 130a38c602..6b9f185918 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -136,9 +136,9 @@ dependencies = [
 
 [[package]]
 name = "anyhow"
-version = "1.0.80"
+version = "1.0.81"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5ad32ce52e4161730f7098c077cd2ed6229b5804ccf99e5366be1ab72a98b4e1"
+checksum = "0952808a6c2afd1aa8947271f3a60f1a6763c7b912d210184c5149b5cf147247"
 
 [[package]]
 name = "argon2"
@@ -479,9 +479,9 @@ checksum = "8c3c1a368f70d6cf7302d78f8f7093da241fb8e8807c05cc9e51a125895a6d5b"
 
 [[package]]
 name = "basic-toml"
-version = "0.1.8"
+version = "0.1.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2db21524cad41c5591204d22d75e1970a2d1f71060214ca931dc7d5afe2c14e5"
+checksum = "823388e228f614e9558c6804262db37960ec8821856535f5c3f59913140558f8"
 dependencies = [
  "serde",
 ]
@@ -3098,6 +3098,9 @@ name = "smallvec"
 version = "1.13.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e6ecd384b10a64542d77071bd64bd7b231f4ed5940fba55e98c3de13824cf3d7"
+dependencies = [
+ "serde",
+]
 
 [[package]]
 name = "socket2"
@@ -3708,18 +3711,18 @@ dependencies = [
 
 [[package]]
 name = "thiserror"
-version = "1.0.57"
+version = "1.0.58"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1e45bcbe8ed29775f228095caf2cd67af7a4ccf756ebff23a306bf3e8b47b24b"
+checksum = "03468839009160513471e86a034bb2c5c0e4baae3b43f79ffc55c4a5427b3297"
 dependencies = [
  "thiserror-impl",
 ]
 
 [[package]]
 name = "thiserror-impl"
-version = "1.0.57"
+version = "1.0.58"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a953cb265bef375dae3de6663da4d3804eee9682ea80d8e2542529b73c531c81"
+checksum = "c61f3ba182994efc43764a46c018c347bc492c79f024e705f46567b418f6d4f7"
 dependencies = [
  "proc-macro2",
  "quote",
diff --git a/sqlx-postgres/Cargo.toml b/sqlx-postgres/Cargo.toml
index 77cc0e2403..ffa40471fc 100644
--- a/sqlx-postgres/Cargo.toml
+++ b/sqlx-postgres/Cargo.toml
@@ -57,7 +57,7 @@ log = "0.4.17"
 memchr = { version = "2.4.1", default-features = false }
 num-bigint = { version = "0.4.3", optional = true }
 once_cell = "1.9.0"
-smallvec = "1.7.0"
+smallvec = { version = "1.7.0", features = ["serde"] }
 stringprep = "0.1.2"
 thiserror = "1.0.35"
 tracing = { version = "0.1.37", features = ["log"] }
diff --git a/sqlx-postgres/src/connection/describe.rs b/sqlx-postgres/src/connection/describe.rs
index 1cd28a8b54..189ae3389b 100644
--- a/sqlx-postgres/src/connection/describe.rs
+++ b/sqlx-postgres/src/connection/describe.rs
@@ -10,6 +10,7 @@ use crate::types::Oid;
 use crate::HashMap;
 use crate::{PgArguments, PgColumn, PgConnection, PgTypeInfo};
 use futures_core::future::BoxFuture;
+use smallvec::SmallVec;
 use std::fmt::Write;
 use std::sync::Arc;
 
@@ -447,20 +448,21 @@ WHERE rngtypid = $1
             explain += ")";
         }
 
-        let (Json([explain]),): (Json<[Explain; 1]>,) = query_as(&explain).fetch_one(self).await?;
+        let (Json(explains),): (Json<SmallVec<[Explain; 1]>>,) =
+            query_as(&explain).fetch_one(self).await?;
 
         let mut nullables = Vec::new();
 
-        if let Explain::Plan {
+        if let Some(Explain::Plan {
             plan:
                 plan @ Plan {
                     output: Some(ref outputs),
                     ..
                 },
-        } = &explain
+        }) = explains.first()
         {
             nullables.resize(outputs.len(), None);
-            visit_plan(plan, outputs, &mut nullables);
+            visit_plan(&plan, outputs, &mut nullables);
         }
 
         Ok(nullables)