From f6f505c41b7479f29f65c2196f162401d263d11b Mon Sep 17 00:00:00 2001
From: Bobbie Soedirgo <bobbie@soedirgo.dev>
Date: Tue, 10 Oct 2023 12:28:13 +0800
Subject: [PATCH] feat: add extra error fields

---
 package-lock.json |  1 +
 package.json      |  1 +
 src/lib/db.ts     | 73 +++++++++++++++++++++++++++++++++++++++++++++--
 src/lib/types.ts  |  5 ++--
 test/lib/query.ts | 20 +++++++++++++
 5 files changed, 95 insertions(+), 5 deletions(-)

diff --git a/package-lock.json b/package-lock.json
index 6febd2ae..98a7f0b3 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -19,6 +19,7 @@
         "pg": "^8.7.1",
         "pg-connection-string": "^2.5.0",
         "pg-format": "^1.0.4",
+        "pg-protocol": "^1.6.0",
         "pgsql-parser": "^13.3.0",
         "pino": "^8.6.1",
         "postgres-array": "^3.0.1",
diff --git a/package.json b/package.json
index 3678ca7e..0e27997a 100644
--- a/package.json
+++ b/package.json
@@ -66,6 +66,7 @@
     "pg": "^8.7.1",
     "pg-connection-string": "^2.5.0",
     "pg-format": "^1.0.4",
+    "pg-protocol": "^1.6.0",
     "pgsql-parser": "^13.3.0",
     "pino": "^8.6.1",
     "postgres-array": "^3.0.1",
diff --git a/src/lib/db.ts b/src/lib/db.ts
index 52834b7a..4324b0be 100644
--- a/src/lib/db.ts
+++ b/src/lib/db.ts
@@ -1,4 +1,5 @@
 import pg, { PoolConfig } from 'pg'
+import { DatabaseError } from 'pg-protocol'
 import { parse as parseArray } from 'postgres-array'
 import { PostgresMetaResult } from './types.js'
 
@@ -76,8 +77,76 @@ export const init: (config: PoolConfig) => {
           res = res.reverse().find((x) => x.rows.length !== 0) ?? { rows: [] }
         }
         return { data: res.rows, error: null }
-      } catch (e: any) {
-        return { data: null, error: { message: e.message } }
+      } catch (error: any) {
+        if (error instanceof DatabaseError) {
+          // Roughly based on:
+          // - https://github.com/postgres/postgres/blob/fc4089f3c65a5f1b413a3299ba02b66a8e5e37d0/src/interfaces/libpq/fe-protocol3.c#L1018
+          // - https://github.com/brianc/node-postgres/blob/b1a8947738ce0af004cb926f79829bb2abc64aa6/packages/pg/lib/native/query.js#L33
+          let formattedError = ''
+          {
+            if (error.severity) {
+              formattedError += `${error.severity}:  `
+            }
+            if (error.code) {
+              formattedError += `${error.code}: `
+            }
+            if (error.message) {
+              formattedError += error.message
+            }
+            formattedError += '\n'
+            if (error.position) {
+              // error.position is 1-based
+              const position = Number(error.position) - 1
+
+              let line = ''
+              let lineNumber = 0
+              let lineOffset = 0
+
+              const lines = sql.split('\n')
+              let currentOffset = 0
+              for (let i = 0; i < lines.length; i++) {
+                if (currentOffset + lines[i].length > position) {
+                  line = lines[i]
+                  lineNumber = i + 1 // 1-based
+                  lineOffset = position - currentOffset
+                  break
+                }
+                currentOffset += lines[i].length + 1 // 1 extra offset for newline
+              }
+              formattedError += `LINE ${lineNumber}: ${line}
+${' '.repeat(5 + lineNumber.toString().length + 2 + lineOffset)}^
+`
+            }
+            if (error.detail) {
+              formattedError += `DETAIL:  ${error.detail}
+`
+            }
+            if (error.hint) {
+              formattedError += `HINT:  ${error.hint}
+`
+            }
+            if (error.internalQuery) {
+              formattedError += `QUERY:  ${error.internalQuery}
+`
+            }
+            if (error.where) {
+              formattedError += `CONTEXT:  ${error.where}
+`
+            }
+          }
+
+          return {
+            data: null,
+            error: {
+              ...error,
+              // error.message is non-enumerable
+              message: error.message,
+              formattedError,
+            },
+          }
+        }
+
+        return { data: null, error: { message: error.message } }
       }
     },
 
diff --git a/src/lib/types.ts b/src/lib/types.ts
index 0e55b35a..333ce631 100644
--- a/src/lib/types.ts
+++ b/src/lib/types.ts
@@ -1,4 +1,5 @@
 import { Static, Type } from '@sinclair/typebox'
+import { DatabaseError } from 'pg-protocol'
 import { Options as PrettierOptions } from 'prettier'
 
 export interface FormatterOptions extends PrettierOptions {}
@@ -10,9 +11,7 @@ export interface PostgresMetaOk<T> {
 
 export interface PostgresMetaErr {
   data: null
-  error: {
-    message: string
-  }
+  error: Partial<DatabaseError> & { message: string; formattedError?: string }
 }
 
 export type PostgresMetaResult<T> = PostgresMetaOk<T> | PostgresMetaErr
diff --git a/test/lib/query.ts b/test/lib/query.ts
index f71ff187..9fe5ab0d 100644
--- a/test/lib/query.ts
+++ b/test/lib/query.ts
@@ -27,7 +27,27 @@ test('error', async () => {
     {
       "data": null,
       "error": {
+        "code": "42P01",
+        "column": undefined,
+        "constraint": undefined,
+        "dataType": undefined,
+        "detail": undefined,
+        "file": "tablecmds.c",
+        "formattedError": "ERROR:  42P01: table "missing_table" does not exist
+    ",
+        "hint": undefined,
+        "internalPosition": undefined,
+        "internalQuery": undefined,
+        "length": 108,
+        "line": "1259",
         "message": "table "missing_table" does not exist",
+        "name": "error",
+        "position": undefined,
+        "routine": "DropErrorMsgNonExistent",
+        "schema": undefined,
+        "severity": "ERROR",
+        "table": undefined,
+        "where": undefined,
       },
     }
   `)