Show comments when tracing expanded statements

[Jason-Abbott]

When trace logs are enabled along with public statements, the output repeats the triggering statement for every table trigger rather than showing the trace trigger comment.

For example, if table foo has two triggers and I do

INSERT INTO foo (one, two) VALUES (1, 2)

the current implementation will log

INSERT INTO foo (one, two) VALUES (1, 2)
INSERT INTO foo (one, two) VALUES (1, 2)
INSERT INTO foo (one, two) VALUES (1, 2)

rather than

INSERT INTO foo (one, two) VALUES (1, 2)
— TRIGGER <trigger name>
— TRIGGER <trigger name>

I am not experienced with C interop so welcome a more efficient way to test for a SQL comment. Also, I didn’t see that this warranted particular documentation since it will just match the behavior of the non-expanded traces.

Pull Request Checklist

• CONTRIBUTING: You have read https://github.com/groue/GRDB.swift/blob/master/CONTRIBUTING.md
• BRANCH: This pull request is submitted against the development branch.
• DOCUMENTATION: Inline documentation has been updated.
• DOCUMENTATION: README.md or another dedicated guide has been updated.
• TESTS: Changes are tested.
• TESTS: The make smokeTest terminal command runs without failure.

[groue]

Hello @Jason-Abbott,

Thank you for this contribution! I understand the itch scratched by this pull request. Traces prefixed with "--" also happen with virtual tables (full text search, for example). Those lines are a useful debugging tool, and I was unaware that expanded SQL would hide them by default.

May I suggest that we take the opportunity to improve the implementation of sql, a few lines above, with an extra commit named "Don't alter trace comments prefixed with --"? This will also make sure both accessors sql and expandedSQL return the same, unprocessed, comment.

 public var sql: String {
     if let unexpandedSQL {
-        return String(cString: unexpandedSQL).trimmedSQLStatement
+        let sql = String(cString: unexpandedSQL)
+        if sql.hasPrefix("--") {
+            return sql
+        } else {
+            return sql.trimmedSQLStatement
+        }
     } else {
         return String(cString: sqlite3_sql(sqliteStatement)).trimmedSQLStatement
     }
 }

I'm looking forward to merging this PR :-)

[Jason-Abbott]

Done!

[groue]

Thank you Jason! Let's wait for the CI and I'll merge shortly 🙂

[groue]

Shipped in v6.29.0 ⛵