Common Errors and Troubleshooting in Programming
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I changed a password in my .env file, restarted MySQL with Docker Compose, and MySQL rejected the new password with ERROR 1045 (28000): Access denied. The container had the new value, but MySQL was still expecting the old one. This post shows why that happens with the official MySQL image, and how I fixed it without deleting any data.
I typed SELECT 'café' into the mysql client inside the official MySQL Docker container, and the client showed 'caf'. The é never appeared on screen and never reached MySQL, and there was no error at all. The container runs without a locale, so the client only accepts plain ASCII. One extra flag on docker compose exec fixes it.
I gave a Microsoft Agent Framework agent a session store so it would remember conversations, and every request started failing with a 500: Agent isolation key is required but was not provided by the configured AgentIsolationKeyProvider. I had configured no provider at all. The default store wanted to know who was calling, and my API had no way to tell it.
A label's formula uses a variable, and Power Apps underlines it in red: Name isn't valid. 'locMember' isn't recognized. The name is spelled correctly. The variable simply doesn't exist yet, because nothing in the app creates it.
Patch fails with Network error when using Patch function: [YourList] ETAG mismatch. It isn't a network problem. The SharePoint item changed after your app read it, so SharePoint refused to overwrite the newer version. Catch it with IfError, tell the person what happened, and reload the item.
You rename a control in Tree view, and Power Apps stops you: Can't rename. This name is already being used. Please try a different name. Another control in the app already has that name, possibly on a different screen.
A control gets a red error icon, and its details say Unexpected characters. Characters are used in the formula in an unexpected way. Power Apps found a character it can't place in one of the control's formulas. In the example it was one closing bracket too many.
A gallery's OnSelect passes the selected row to another screen, and Power Apps marks it as an error: Incompatible type. We can't evaluate your formula because the context variable types are incompatible with the types of values in other places in your app. In the example, Self.Selected caused it, and ThisItem fixed it.
Focus isn't showing in the App checker means a control's focus border has a thickness of 0. Someone moving through the app with the keyboard can't see when they've landed on it. For anything they can tab to, give it a border; for a control they can't tab to, the border never appears anyway.
The App checker lists Missing tab stop under Accessibility errors: a control it considers interactive has no place in the keyboard's Tab order. For a gallery, the fix is TabIndex 0. For a plain heading, Microsoft's guidance points the other way, so think before you change it.
