src/goCover: ignore bogus-looking line/column data

Go's line directive can cause the coverage data to include bogus
line/column info.

The extension naively assumed the coverage data position info is
always valid and line/column numbers are 1-based sane numbers. Of course,
that's not always true any more.

The example in #2453 generated the following coverage data.

  mode: set
  blah/blah.go:3.16,5.2 1 1
  blah/blah.go:7.16,9.2 1 1
  blah/blah.go:13.16,98989.0 2 1
  blah/blah.go:98992.0,98993.0 2 1
  blah/blah.go:98989.0,98991.0 1 0

The column values were 0. The extension blindly converted them to 0-based
positions by subtracting 1. This illegal range eventually made the vscode to
throw an exception eventually.

I think the go test -cover shouldn't use the bogus line/col info in
coverage profile, but that is another issue.

It does not make sense to map such bogus numbers, so, this CL filters them
out.

For golang/go#41222
Fixes #2453

Change-Id: I31a28fecae0a01406e0dc32c48dca1fb4f7b6f0c
Reviewed-on: https://go-review.googlesource.com/c/vscode-go/+/447957
Run-TryBot: Hyang-Ah Hana Kim <[email protected]>
TryBot-Result: kokoro <[email protected]>
Reviewed-by: Peter Weinberger <[email protected]>
Reviewed-by: Than McIntosh <[email protected]>

Author: hyangah

src/goCover.ts

@@ -261,13 +261,25 @@ export function applyCodeCoverageToAllEditors(coverProfilePath: string, dir?: st
 
 				// and fill in coveragePath
 				const coverage = coveragePath.get(parse[1]) || emptyCoverageData();
+				// When line directive is used this information is artificial and
+				// the source code file can be non-existent or wrong (go.dev/issues/41222).
+				// There is no perfect way to guess whether the line/col in coverage profile
+				// is bogus. At least, we know that 0 or negative values are not true line/col.
+				const startLine = parseInt(parse[2], 10);
+				const startCol = parseInt(parse[3], 10);
+				const endLine = parseInt(parse[4], 10);
+				const endCol = parseInt(parse[5], 10);
+				if (startLine < 1 || startCol < 1 || endLine < 1 || endCol < 1) {
+					return;
+				}
 				const range = new vscode.Range(
 					// Convert lines and columns to 0-based
-					parseInt(parse[2], 10) - 1,
-					parseInt(parse[3], 10) - 1,
-					parseInt(parse[4], 10) - 1,
-					parseInt(parse[5], 10) - 1
+					startLine - 1,
+					startCol - 1,
+					endLine - 1,
+					endCol - 1
 				);
+
 				const counts = parseInt(parse[7], 10);
 				// If is Covered (CoverCount > 0)
 				if (counts > 0) {

test/integration/coverage.test.ts

@@ -9,9 +9,7 @@
 import assert from 'assert';
 import { applyCodeCoverageToAllEditors, coverageFilesForTest, initForTest } from '../../src/goCover';
 import { updateGoVarsFromConfig } from '../../src/goInstallTools';
-import fs = require('fs-extra');
 import path = require('path');
-import sinon = require('sinon');
 import vscode = require('vscode');
 
 // The ideal test would check that each open editor containing a file with coverage
@@ -39,6 +37,11 @@ suite('Coverage for tests', function () {
 		const files = Object.keys(coverageFilesForTest());
 		const aDotGo = files.includes(path.join(fixtureSourcePath, 'a', 'a.go'));
 		const bDotGo = files.includes(path.join(fixtureSourcePath, 'b', 'b.go'));
-		assert.equal(aDotGo && bDotGo, true, `seen a.go:${aDotGo}, seen b.go:${bDotGo}\n${files}\n`);
+		// Coverage data (cover.out) contains a couple of bogus data with file name blah.go. They shouldn't appear.
+		const blahDotGo = files.includes(path.join(fixtureSourcePath, 'b', 'blah.go'));
+		assert(
+			aDotGo && bDotGo && !blahDotGo,
+			`!seen a.go:${aDotGo} or !seen b.go:${bDotGo} or seen blah.go:${blahDotGo}: ${files}\n`
+		);
 	});
 });

test/testdata/coverage/cover.out

@@ -1,3 +1,5 @@
 mode: set
 github.com/microsoft/vscode-go/gofixtures/coveragetest/a/a.go:19.71,22.25 3 1
 github.com/microsoft/vscode-go/gofixtures/coveragetest/b/b.go:35.2,35.14 1 1
+github.com/microsoft/vscode-go/gofixtures/coveragetest/b/blah.go:13.16,98989.0 2 1
+github.com/microsoft/vscode-go/gofixtures/coveragetest/b/blah.go:98992.0,98993.0 -2 1