René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Improve the configuration APIs in PSConfiguration.cs","articleBody":"The tasks that I can think of are:\r\n1. maybe replace the singleton with static methods\r\n2. schema check\r\n3. synchronize updating the configuration file from multiple processes.\r\n   - we currently have a read/write lock to protect updating/reading the config file. The lock doesn't help synchronize writing access from multiple processes.\r\n4. holding the config file in one process (e.g. `write` access or `none` share) will cause a new pwsh instance to crash at startup because it cannot access the config file and we don't deal with the `IOException`.\r\n   - we could return default value when the config file is not accessible, but need to consider to not allow bypassing security settings because of that.\r\n      - one option: have two sets of default values for security settings. One set is used when the config file doesn't exist or the security setting is not defined in the file; the other set is used when the file exists but not accessible, to enforce all security features that are configurable in the config file.\r\n\r\n#### Repro step for 4:\r\nFirst, run the following code to hold the config file of the current pwsh\r\n```\r\n$path = \"path-to-powershell.config.json\"\r\n$mode = \"Open\"\r\n$access = \"Read\"\r\n$share = \"None\"\r\n\r\n$file = [System.IO.File]::Open($path, $mode, $access, $share)\r\n```\r\nThen, start a new instance of the pwsh, and it will crash.","author":{"url":"https://github.com/daxian-dbw","@type":"Person","name":"daxian-dbw"},"datePublished":"2018-01-06T23:55:38.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":10},"url":"https://github.com/5809/PowerShell/issues/5809"}