From 494bd92f1b68950c246040bfcff4f0a18c4f05b0 Mon Sep 17 00:00:00 2001
From: Sheetal Nandi <shkamat@microsoft.com>
Date: Thu, 21 Feb 2019 19:05:30 -0800
Subject: [PATCH] Report error if overwriting buildInfo of another project
 reference

---
 src/compiler/diagnosticMessages.json        |  4 ++++
 src/compiler/emitter.ts                     |  4 ++++
 src/compiler/program.ts                     |  6 +++++
 src/testRunner/unittests/tsbuild/outFile.ts | 26 +++++++++++++++++++++
 4 files changed, 40 insertions(+)

diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index bd971b1542d..f42baa79a82 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -4016,6 +4016,10 @@
         "category": "Message",
         "code": 6376
     },
+    "Cannot write file '{0}' because it will overwrite '.tsbuildinfo' of referenced project '{1}'": {
+        "category": "Error",
+        "code": 6377
+    },
 
     "The expected type comes from property '{0}' which is declared here on type '{1}'": {
         "category": "Message",
diff --git a/src/compiler/emitter.ts b/src/compiler/emitter.ts
index 9a2c0e111df..f392daf3c41 100644
--- a/src/compiler/emitter.ts
+++ b/src/compiler/emitter.ts
@@ -186,6 +186,10 @@ namespace ts {
             if (!buildInfoPath || targetSourceFile || emitSkipped) return;
             const program = host.getProgramBuildInfo();
             if (!bundle && !program) return;
+            if (host.isEmitBlocked(buildInfoPath) || compilerOptions.noEmit) {
+                emitSkipped = true;
+                return;
+            }
             writeFile(host, emitterDiagnostics, buildInfoPath, getBuildInfoText({ bundle, program }), /*writeByteOrderMark*/ false);
         }
 
diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index 24aa9974ebf..c30317b1142 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -2941,6 +2941,7 @@ namespace ts {
         }
 
         function verifyProjectReferences() {
+            const buildInfoPath = !options.noEmit && !options.suppressOutputPathCheck ? getOutputPathForBuildInfo(options, projectReferences) : undefined;
             forEachProjectReference(projectReferences, resolvedProjectReferences, (resolvedRef, index, parent) => {
                 const ref = (parent ? parent.commandLine.projectReferences : projectReferences)![index];
                 const parentFile = parent && parent.sourceFile as JsonSourceFile;
@@ -2967,6 +2968,11 @@ namespace ts {
                         createDiagnosticForReference(parentFile, index, Diagnostics.Cannot_prepend_project_0_because_it_does_not_have_outFile_set, ref.path);
                     }
                 }
+                const refBuildInfoPath = getOutputPathForBuildInfo(options, resolvedRef.commandLine.projectReferences);
+                if (refBuildInfoPath && refBuildInfoPath === buildInfoPath) {
+                    createDiagnosticForReference(parentFile, index, Diagnostics.Cannot_write_file_0_because_it_will_overwrite_tsbuildinfo_of_referenced_project_1, buildInfoPath, ref.path);
+                    hasEmitBlockingDiagnostics.set(toPath(buildInfoPath), true);
+                }
             });
         }
 
diff --git a/src/testRunner/unittests/tsbuild/outFile.ts b/src/testRunner/unittests/tsbuild/outFile.ts
index 787928d383d..d4970291785 100644
--- a/src/testRunner/unittests/tsbuild/outFile.ts
+++ b/src/testRunner/unittests/tsbuild/outFile.ts
@@ -478,6 +478,32 @@ namespace ts {
             );
         });
 
+        it("verify that if multiple projects write tsbuildinfo to same location, reports error", () => {
+            const fs = outFileFs.shadow();
+            const host = new fakes.SolutionBuilderHost(fs);
+            replaceText(fs, sources[project.first][source.config], "./bin/first-output.js", "../bin/first-output.js");
+            replaceText(fs, sources[project.second][source.config], "../2/second-output.js", "../bin/second-output.js");
+            replaceText(fs, sources[project.third][source.config], "./thirdjs/output/third-output.js", "../bin/third-output.js");
+            const builder = createSolutionBuilder(host);
+            builder.buildAllProjects();
+            host.assertDiagnosticMessages(
+                getExpectedDiagnosticForProjectsInBuild(relSources[project.first][source.config], relSources[project.second][source.config], relSources[project.third][source.config]),
+                [Diagnostics.Project_0_is_out_of_date_because_output_file_1_does_not_exist, relSources[project.first][source.config], "src/bin/first-output.js"],
+                [Diagnostics.Building_project_0, sources[project.first][source.config]],
+                [Diagnostics.Project_0_is_out_of_date_because_output_file_1_does_not_exist, relSources[project.second][source.config], "src/bin/second-output.js"],
+                [Diagnostics.Building_project_0, sources[project.second][source.config]],
+                [Diagnostics.Project_0_is_out_of_date_because_output_file_1_does_not_exist, relSources[project.third][source.config], "src/bin/third-output.js"],
+                [Diagnostics.Building_project_0, sources[project.third][source.config]],
+                [Diagnostics.Cannot_write_file_0_because_it_will_overwrite_tsbuildinfo_of_referenced_project_1, "/src/bin/.tsbuildinfo", "/src/first"],
+                [Diagnostics.Cannot_write_file_0_because_it_will_overwrite_tsbuildinfo_of_referenced_project_1, "/src/bin/.tsbuildinfo", "/src/second"]
+            );
+            // Verify they exist
+            for (const output of ["/src/bin/first-output.js", "/src/bin/second-output.js"]) {
+                assert(fs.existsSync(output), `Expect file ${output} to exist`);
+            }
+            assert.isFalse(fs.existsSync("/src/bin/third-output.js"), `Expect file "/src/bin/third-output.js" to not exist`);
+        });
+
         // Prologues
         function enableStrict(fs: vfs.FileSystem, path: string) {
             replaceText(fs, path, `"strict": false`, `"strict": true`);