mention glob syntax in entry point errors (#976)

CHANGELOG.md

@@ -38,6 +38,10 @@
 
     This problem occurs because this package doesn't provide an import path for ESM code using the `import` condition and also doesn't provide a fallback import path using the `default` condition.
 
+* Mention glob syntax in entry point error messages ([#976](https://github.com/evanw/esbuild/issues/976))
+
+    In this release, including a `*` in the entry point path now causes the failure message to tell you that glob syntax must be expanded first before passing the paths to esbuild. People that hit this are usually converting an existing CLI command to a JavaScript API call and don't know that glob expansion is done by their shell instead of by esbuild. An appropriate fix is to use a library such as [`glob`](https://www.npmjs.com/package/glob) to expand the glob pattern first before passing the paths to esbuild.
+
 * Raise certain VM versions in the JavaScript feature compatibility table
 
     JavaScript VM feature compatibility data is derived from this dataset: https://kangax.github.io/compat-table/. The scripts that process the dataset expand the data to include all VM versions that support a given feature (e.g. `chrome44`, `chrome45`, `chrome46`, ...) so esbuild takes the minimum observed version as the first version for which the feature is supported.

internal/bundler/bundler.go

@@ -1223,7 +1223,9 @@ func (s *scanner) addEntryPoints(entryPoints []string) []uint32 {
 			} else if !didLogError {
 				hint := ""
 				if !s.fs.IsAbs(path) {
-					if query := s.res.ProbeResolvePackageAsRelative(entryPointAbsResolveDir, path, ast.ImportEntryPoint); query != nil {
+					if strings.ContainsRune(path, '*') {
+						hint = " (glob syntax must be expanded first before passing the paths to esbuild)"
+					} else if query := s.res.ProbeResolvePackageAsRelative(entryPointAbsResolveDir, path, ast.ImportEntryPoint); query != nil {
 						hint = fmt.Sprintf(" (use %q to reference the file %q)", "./"+path, s.res.PrettyPath(query.PathPair.Primary))
 					}
 				}

scripts/js-api-tests.js

@@ -44,6 +44,22 @@ let buildTests = {
     }
   },
 
+  async errorIfGlob({ esbuild }) {
+    try {
+      await esbuild.build({
+        entryPoints: ['./src/*.js'],
+        logLevel: 'silent',
+        write: false,
+      })
+      throw new Error('Expected build failure');
+    } catch (e) {
+      if (!e.errors || !e.errors[0] || e.errors[0].text !== 'Could not resolve "./src/*.js" ' +
+        '(glob syntax must be expanded first before passing the paths to esbuild)') {
+        throw e;
+      }
+    }
+  },
+
   async workingDirTest({ esbuild, testDir }) {
     let aDir = path.join(testDir, 'a');
     let bDir = path.join(testDir, 'b');