Error handling koans #153
Error handling koans #153
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vexx32
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| Error Handling in PowerShell | ||
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| PowerShell handles errors via the System.Management.Automation.ErrorRecord class. These objects form | ||
| the basic unit of "an error" in PowerShell. |
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Seeing this sentence after coming here to learn about errors I'd be very confused. It is overly technical but also abstract. What does >>basic unit of "an error"<< even mean? I'd rephrase it with a beginner in mind, without trying to squeeze too much ideas into the first sentence they see.
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Hmm, good point. Maybe something more like Each error is represented in PowerShell by a corresponding ErrorRecord object.?
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IDK, is that the first thing to learn about errors? I'd start from the terminating, non-terminating categorisation. You are mentioning ErrorRecord before the first task, so I'd just delete this.
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I'm not sure it would make any sense to talk about errors at all in PowerShell before at least giving an overview of what they are... 😕
| PowerShell handles errors via the System.Management.Automation.ErrorRecord class. These objects form | ||
| the basic unit of "an error" in PowerShell. | ||
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| Errors can be flagged as terminating or non-terminating based on a few different criteria, largely |
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Flagged by who, based on which criteria? :) Be more authoritative, you are the teacher here. It does not matter that you leave out some detail or an edge-case. Give solid facts first. "Errors in PowerShell are terminating and non-terminating. The type of error that a command throws depends on the severity of the error. If the command cannot continue it throws a terminating error, if it can continue it throws a non-terminating error.
example 1: a built-in cmdlet throwing terminating error
example 2: a built-in cmdlet throwing non-terminating error
To handle terminating errors we use try/catch etc...
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Authoritative is a bit much I feel, but I know what you mean. I'll see how I can rephrase this 😄
| metadata that you can work with if you come across an error. | ||
| #> | ||
| BeforeAll { | ||
| $Record = try { |
| Note that specifying the exception type is optional. A "generic" catch block (no exception type | ||
| specified) will simply catch everything. If you know the errors you're looking for, it's often | ||
| best to only catch the ones you're expecting. If something else happens, you might make matters | ||
| worse by handling that the same way as the errors you were expecting. |
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A short example of bad error handling practice might be useful here e.g. try { throw [InvalidOperationException]"Cannot write into file log.txt" } catch { Write-Host "Cannot connect to network" }
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That's a good idea, thanks!
vexx32
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@nohwnd if you have a moment to check through my latest changes and let me know if there's anything more that needs tinkering with, I'd greatly appreciate it <3 |
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PR Summary
Add error handling koans!
TODO
catch [Type] {}try{} finally{}trap{}[shudder] exampleAdd(this should be included in Add Topic - AboutCommonParameters / AboutPreferenceVariables #154 instead)-ErrorActionand$ErrorActionPreferenceexamples