Assume no terminal if the display width/height is 0 (#5959)

CHANGELOG.md

@@ -16,6 +16,9 @@ CHANGELOG
 - Fix a bug in the core engine where ComponentResource state would be accessed before initialization.
   [#5949](https://github.com/pulumi/pulumi/pull/5949)
 
+- Prevent a panic by not attempting to show progress for zero width/height terminals.
+  [#5957](https://github.com/pulumi/pulumi/issues/5957)
+
 ## 2.15.6 (2020-12-12)
 
 - Fix a bug in the Go SDK that could result in dropped resource dependencies.

pkg/backend/display/progress.go

@@ -327,6 +327,13 @@ func ShowProgressEvents(op string, action apitype.UpdateKind, stack tokens.QName
 			display.terminalWidth = terminalWidth
 			display.terminalHeight = terminalHeight
 
+			// Don't bother attempting to treat this display as a terminal if it has no width/height.
+			if display.isTerminal && (display.terminalWidth == 0 || display.terminalHeight == 0) {
+				display.isTerminal = false
+				_, err = fmt.Fprintln(stderr, "Treating display as non-terminal due to 0 width/height.")
+				contract.IgnoreError(err)
+			}
+
 			// Fetch the canonical stdout stream, configured appropriately.
 			_, stdout, _ = term.StdStreams()
 		}