main: synchronize writes to VT100-faker on Windows #14194
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We use a third-party library "colorable" to translate VT100 color sequences into Windows console attribute-setting calls when Terraform is running on Windows. colorable is not concurrency-safe for multiple writes to the same console, because it writes to the console one character at a time and so two concurrent writers get their characters interleaved, creating unreadable garble. Here we wrap around it a synchronization mechanism to ensure that there can be only one Write call outstanding across both stderr and stdout, mimicking the usual behavior we expect (when stderr/stdout are a normal file handle) of each Write being completed atomically.
jbardin
approved these changes
May 4, 2017
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Before:
After:
We use a third-party library "colorable" to translate VT100 color sequences into Windows console attribute-setting calls when Terraform is running on Windows.
colorable is not concurrency-safe for multiple writes to the same console, because it writes to the console one character at a time and so two concurrent writers get their characters interleaved, creating unreadable garble.
Here we wrap around it a synchronization mechanism to ensure that there can be only one Write call outstanding across both stderr and stdout, mimicking the usual behavior we expect (when stderr/stdout are a normal file handle) of each Write being completed atomically.
This fixes #11363.