feat: Allow nyc instrument to instrument code in place

docs/instrument.md

@@ -20,15 +20,17 @@ For example, `nyc instrument . ./output` will produce instrumented versions of a
 
 The `--delete` option will remove the existing output directory before instrumenting.
 
+The '--in-place' option will allow you to run the instrument command
+
 The `--complete-copy` option will copy all remaining files from the `input` directory to the `output` directory.
 When using `--complete-copy` nyc will not copy the contents of a `.git` folder to the output directory.
 
 **Note:** `--complete-copy` will dereference any symlinks during the copy process, this may stop scripts running properly from the output directory.
 
 ## Streaming instrumentation
 
-`nyc instrument` will stream instrumented source directly to `stdout`, that can then be piped to another process.
-You can use this behaviour to create a server that can instrument files on request.
+`nyc instrument <input>` will stream instrumented source directly to `stdout` and that output can then be piped to another process.
+You can use this behaviour to create a server that dynamically instruments files on request.
 The following example shows streaming instrumentation middleware capable of instrumenting files on request.
 
 ```javascript

lib/commands/instrument.js

@@ -31,32 +31,37 @@ exports.builder = function (yargs) {
     .option('source-map', {
       default: true,
       type: 'boolean',
-      description: 'should nyc detect and handle source maps?'
+      describe: 'should nyc detect and handle source maps?'
     })
     .option('produce-source-map', {
       default: false,
       type: 'boolean',
-      description: "should nyc's instrumenter produce source maps?"
+      describe: "should nyc's instrumenter produce source maps?"
     })
     .option('compact', {
       default: true,
       type: 'boolean',
-      description: 'should the output be compacted?'
+      describe: 'should the output be compacted?'
     })
     .option('preserve-comments', {
       default: true,
       type: 'boolean',
-      description: 'should comments be preserved in the output?'
+      describe: 'should comments be preserved in the output?'
     })
     .option('instrument', {
       default: true,
       type: 'boolean',
-      description: 'should nyc handle instrumentation?'
+      describe: 'should nyc handle instrumentation?'
+    })
+    .option('in-place', {
+      default: false,
+      type: 'boolean',
+      describe: 'should nyc run the instrumentation in place?'
     })
     .option('exit-on-error', {
       default: false,
       type: 'boolean',
-      description: 'should nyc exit when an instrumentation failure occurs?'
+      describe: 'should nyc exit when an instrumentation failure occurs?'
     })
     .option('include', {
       alias: 'n',
@@ -92,40 +97,45 @@ exports.builder = function (yargs) {
     .example('$0 instrument ./lib ./output', 'instrument all .js files in ./lib with coverage and output in ./output')
 }
 
+const errorExit = msg => {
+  console.error(`nyc instrument failed:  ${msg}`)
+  process.exitCode = 1
+}
+
 exports.handler = function (argv) {
-  if (argv.output && (path.resolve(argv.cwd, argv.input) === path.resolve(argv.cwd, argv.output))) {
-    console.error(`nyc instrument failed: cannot instrument files in place, <input> must differ from <output>`)
-    process.exitCode = 1
-    return
+  if (argv.output && !argv.inPlace && (path.resolve(argv.cwd, argv.input) === path.resolve(argv.cwd, argv.output))) {
+    return errorExit(`cannot instrument files in place, <input> must differ from <output>.  Set '--in-place' to force`)
   }
 
   if (path.relative(argv.cwd, path.resolve(argv.cwd, argv.input)).startsWith('..')) {
-    console.error(`nyc instrument failed: cannot instrument files outside of project root directory`)
-    process.exitCode = 1
-    return
+    return errorExit('cannot instrument files outside project root directory')
+  }
+
+  if (argv.delete && argv.inPlace) {
+    return errorExit(`cannot use '--delete' when instrumenting files in place`)
   }
 
   if (argv.delete && argv.output && argv.output.length !== 0) {
     const relPath = path.relative(process.cwd(), path.resolve(argv.output))
     if (relPath !== '' && !relPath.startsWith('..')) {
       rimraf.sync(argv.output)
     } else {
-      console.error(`nyc instrument failed: attempt to delete '${process.cwd()}' or containing directory.`)
-      process.exit(1)
+      return errorExit(`attempt to delete '${process.cwd()}' or containing directory.`)
     }
   }
 
+  console.log(`Running nyc from ${process.cwd()}`)
+
   // If instrument is set to false enable a noop instrumenter.
   argv.instrumenter = (argv.instrument)
     ? './lib/instrumenters/istanbul'
     : './lib/instrumenters/noop'
 
-  const nyc = new NYC(argv)
+  if (argv.inPlace) {
+    argv.output = argv.input
+    argv.completeCopy = false
+  }
 
-  nyc.instrumentAllFiles(argv.input, argv.output, err => {
-    if (err) {
-      console.error(err.message)
-      process.exitCode = 1
-    }
-  })
+  const nyc = new NYC(argv)
+  nyc.instrumentAllFiles(argv.input, argv.output, err => err ? errorExit(err.message) : null)
 }

test/fixtures/cli/instrument-inplace/file1.js

@@ -0,0 +1,5 @@
+function test() {
+  return 'file1'
+}
+
+module.exports = test

test/fixtures/cli/instrument-inplace/file2.js

@@ -0,0 +1,5 @@
+function test() {
+	return 'file2'
+}
+
+module.exports = test

test/nyc-integration-old.js

@@ -329,7 +329,53 @@ describe('the nyc cli', function () {
 
         const proc = spawn(process.execPath, args, {
           cwd: fixturesCLI,
-          env: env
+          env
+        })
+
+        let stderr = ''
+        proc.stderr.on('data', function (chunk) {
+          stderr += chunk
+        })
+
+        proc.on('close', function (code) {
+          code.should.equal(1)
+          stderr.should.include('cannot instrument files in place')
+          done()
+        })
+      })
+
+      it('can write files in place with --in-place switch', function (done) {
+        const args = [bin, 'instrument', '--in-place', '--include', '*/file1.js', './instrument-inplace']
+
+        const proc = spawn(process.execPath, args, {
+          cwd: fixturesCLI,
+          env
+        })
+
+        let stderr = ''
+        proc.stderr.on('data', function (chunk) {
+          stderr += chunk
+        })
+
+        proc.on('close', function (code) {
+          console.log(`stderr:  ${stderr}`)
+          code.should.equal(0)
+          const file1 = path.resolve(fixturesCLI, 'instrument-inplace', 'file1.js')
+          fs.readFileSync(file1, 'utf8')
+            .should.match(/var cov_/)
+          const file2 = path.resolve(fixturesCLI, 'instrument-inplace', 'file2.js')
+          fs.readFileSync(file2, 'utf8')
+            .should.not.match(/var cov_/)
+          done()
+        })
+      })
+
+      it('aborts if trying to delete while writing files in place', function (done) {
+        const args = [bin, 'instrument', '--in-place', '--delete', '--include', 'file1.js', './instrument-inplace']
+
+        const proc = spawn(process.execPath, args, {
+          cwd: fixturesCLI,
+          env
         })
 
         let stderr = ''
@@ -339,7 +385,7 @@ describe('the nyc cli', function () {
 
         proc.on('close', function (code) {
           code.should.equal(1)
-          stderr.should.include('nyc instrument failed: cannot instrument files in place')
+          stderr.should.include(`cannot use '--delete' when instrumenting files in place`)
           done()
         })
       })
@@ -349,7 +395,7 @@ describe('the nyc cli', function () {
 
         const proc = spawn(process.execPath, args, {
           cwd: fixturesCLI,
-          env: env
+          env
         })
 
         let stderr = ''
@@ -359,7 +405,7 @@ describe('the nyc cli', function () {
 
         proc.on('close', function (code) {
           code.should.equal(1)
-          stderr.should.include('nyc instrument failed: cannot instrument files outside of project root directory')
+          stderr.should.include('cannot instrument files outside project root directory')
           done()
         })
       })
@@ -374,7 +420,7 @@ describe('the nyc cli', function () {
 
           const proc = spawn(process.execPath, args, {
             cwd: fixturesCLI,
-            env: env
+            env
           })
 
           proc.on('close', function (code) {
@@ -393,7 +439,7 @@ describe('the nyc cli', function () {
 
           const proc = spawn(process.execPath, args, {
             cwd: fixturesCLI,
-            env: env
+            env
           })
 
           proc.on('close', function (code) {
@@ -411,7 +457,7 @@ describe('the nyc cli', function () {
 
           const proc = spawn(process.execPath, args, {
             cwd: fixturesCLI,
-            env: env
+            env
           })
 
           let stderr = ''
@@ -421,7 +467,7 @@ describe('the nyc cli', function () {
 
           proc.on('close', function (code) {
             code.should.equal(1)
-            stderr.should.include('nyc instrument failed: attempt to delete')
+            stderr.should.include('attempt to delete')
             done()
           })
         })
@@ -431,7 +477,7 @@ describe('the nyc cli', function () {
 
           const proc = spawn(process.execPath, args, {
             cwd: fixturesCLI,
-            env: env
+            env
           })
 
           let stderr = ''
@@ -441,7 +487,7 @@ describe('the nyc cli', function () {
 
           proc.on('close', function (code) {
             code.should.equal(1)
-            stderr.should.include('nyc instrument failed: attempt to delete')
+            stderr.should.include('attempt to delete')
             done()
           })
         })