Fix escapingio handling of \n~\n

CHANGELOG.md

@@ -17,6 +17,7 @@ BUG FIXES:
  * csi: Fixed a bug where querying CSI volumes would cause a panic if an allocation that claimed the volume had been garbage collected but the claim was not yet dropped. [[GH-8735](https://github.com/hashicorp/nomad/issues/8735)]
  * deployments (Enterprise): Fixed a bug where counts could not be changed in the web UI for multiregion jobs. [[GH-8685](https://github.com/hashicorp/nomad/issues/8685)]
  * deployments (Enterprise): Fixed a bug in multi-region deployments where a region that was dropped from the jobspec was not deregistered. [[GH-8763](https://github.com/hashicorp/nomad/issues/8763)]
+ * exec: Fixed a bug causing escape characters to be missed in special cases [[GH-8798](https://github.com/hashicorp/nomad/issues/8798)]
  * plan: Fixed a bug where plans always included a change for the `NomadTokenID`. [[GH-8559](https://github.com/hashicorp/nomad/issues/8559)]
 
 ## 0.12.3 (August 13, 2020)

helper/escapingio/reader.go

@@ -93,6 +93,9 @@ func (r *reader) pipe() {
 						bw.WriteByte(r.escapeChar)
 						bw.WriteByte(rb[0])
 						bw.Flush()
+						if rb[0] == '\n' || rb[0] == '\r' {
+							state = sLookEscapeChar
+						}
 					}
 				}
 			}
@@ -137,6 +140,10 @@ START:
 			bw.Write(buf[wi:i])
 			i = i + 2
 			wi = i
+		} else if nc == '\n' || nc == '\r' {
+			i = i + 2
+			s = sLookEscapeChar
+			goto START
 		} else {
 			i = i + 2
 			// need to write everything keep going

helper/escapingio/reader_test.go

@@ -42,6 +42,7 @@ func TestEscapingReader_Static(t *testing.T) {
 		{"\n~.", "\n", "."},
 		{"~", "~", ""},
 		{"\r~.", "\r", "."},
+		{"b\n~\n~.q", "b\n~\nq", "."},
 	}
 
 	for _, c := range cases {