Add config extends and entry point exclusion

Profiles may inherit from another config file (extends: <path>): the
first profile of the referenced file is merged underneath (scalars from
the overlay win, slices concatenate base-first and de-duplicate, chains
resolve recursively, cycles are detected).

esbuild.excludeEntryPoints removes merged entry points by glob (** spans
path separators, * stays within a segment), applied after path
resolution so patterns and entries match in the same shape.

Lets product editions/flavors (e.g. the wmd4x Range Trader Pro edition)
build only their own entry set on top of a shared, merge-clean base
config. Includes unit tests and template docs.

config_test.go

@@ -0,0 +1,156 @@
+package main
+
+import (
+	"os"
+	"path/filepath"
+	"reflect"
+	"regexp"
+	"testing"
+)
+
+func TestMergeOptions(t *testing.T) {
+	base := options{}
+	base.ESBuild.EntryPoints = []string{"a.js", "b.js"}
+	base.ESBuild.LogLevel = 3
+	base.ESBuild.Splitting = true
+	base.Copy = []struct {
+		Src  string `yaml:"src"`
+		Dest string `yaml:"dest"`
+	}{{Src: "index.html", Dest: "dist"}}
+
+	overlay := options{}
+	overlay.ESBuild.EntryPoints = []string{"b.js", "c.js"} // b.js duplicates the base
+	overlay.ESBuild.LogLevel = 2                           // scalar override
+	overlay.Copy = []struct {
+		Src  string `yaml:"src"`
+		Dest string `yaml:"dest"`
+	}{{Src: "index.html", Dest: "dist"}} // exact duplicate of the base entry
+
+	merged := mergeOptions(base, overlay)
+
+	want := []string{"a.js", "b.js", "c.js"}
+	if !reflect.DeepEqual(merged.ESBuild.EntryPoints, want) {
+		t.Fatalf("entryPoints = %v, want %v", merged.ESBuild.EntryPoints, want)
+	}
+
+	if merged.ESBuild.LogLevel != 2 {
+		t.Fatalf("logLevel = %d, want overlay value 2", merged.ESBuild.LogLevel)
+	}
+
+	if !merged.ESBuild.Splitting {
+		t.Fatal("splitting = false, want inherited true")
+	}
+
+	if len(merged.Copy) != 1 {
+		t.Fatalf("copy = %d entries, want de-duplicated 1", len(merged.Copy))
+	}
+
+	if merged.Extends != "" {
+		t.Fatalf("extends = %q, want cleared after merge", merged.Extends)
+	}
+}
+
+func TestPatternToRegexp(t *testing.T) {
+	cases := []struct {
+		pattern string
+		path    string
+		match   bool
+	}{
+		// Production shape: processPaths absolutizes patterns and entries
+		// alike, so matching happens between absolute forward-slash paths.
+		{"/proj/apps/taxes/**", "/proj/apps/taxes/taxes-app.js", true},
+		{"/proj/apps/taxes/**", "/proj/apps/taxes/elements/tax-script.js", true},
+		{"/proj/apps/taxes/**", "/proj/apps/journal/journal-app.js", false},
+		{"/proj/apps/vault/**", "/proj/apps/vaultx/vaultx-app.js", false},
+		{"/proj/src/*.js", "/proj/src/the-app.js", true},
+		{"/proj/src/*.js", "/proj/src/admin/the-admin.js", false},
+		{"/proj/src/the-?.js", "/proj/src/the-a.js", true},
+		{"/proj/src/the-?.js", "/proj/src/the-ab.js", false},
+	}
+
+	for _, c := range cases {
+		re := regexp.MustCompile(patternToRegexp(c.pattern))
+		if re.MatchString(c.path) != c.match {
+			t.Errorf("pattern %q vs %q: got %v, want %v", c.pattern, c.path, re.MatchString(c.path), c.match)
+		}
+	}
+}
+
+func TestFilterEntryPoints(t *testing.T) {
+	opts := options{}
+	opts.ESBuild.EntryPoints = []string{
+		"/proj/apps/taxes/taxes-app.js",
+		"/proj/apps/chat/chat-app.js",
+		"/proj/the-terminal.js",
+	}
+	opts.ESBuild.ExcludeEntryPoints = []string{"/proj/apps/taxes/**"}
+
+	filterEntryPoints(&opts)
+
+	want := []string{"/proj/apps/chat/chat-app.js", "/proj/the-terminal.js"}
+	if !reflect.DeepEqual(opts.ESBuild.EntryPoints, want) {
+		t.Fatalf("entryPoints = %v, want %v", opts.ESBuild.EntryPoints, want)
+	}
+}
+
+func TestReadCfgExtends(t *testing.T) {
+	dir := t.TempDir()
+	prevWd, err := os.Getwd()
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() { os.Chdir(prevWd) })
+
+	writeFile := func(name, content string) {
+		if err := os.WriteFile(filepath.Join(dir, name), []byte(content), 0644); err != nil {
+			t.Fatal(err)
+		}
+	}
+
+	writeFile("base.yaml", `- esbuild:
+    entryPoints:
+        - ./src/base-one.js
+        - ./src/base-two.js
+    outdir: ./dist
+    logLevel: 3
+  copy:
+    - src: ./index.html
+      dest: ./dist
+`)
+
+	writeFile("overlay.yaml", `- extends: ./base.yaml
+  esbuild:
+    entryPoints:
+        - ./src/base-two.js
+        - ./src/overlay.js
+    excludeEntryPoints:
+        - ./src/base-one.js
+`)
+
+	if err := os.Chdir(dir); err != nil {
+		t.Fatal(err)
+	}
+
+	profiles := readCfg("./overlay.yaml")
+	if len(profiles) != 1 {
+		t.Fatalf("profiles = %d, want 1", len(profiles))
+	}
+
+	p := profiles[0]
+	want := []string{
+		filepath.Join(dir, "src/base-two.js"),
+		filepath.Join(dir, "src/overlay.js"),
+	}
+
+	if !reflect.DeepEqual(p.ESBuild.EntryPoints, want) {
+		t.Fatalf("entryPoints = %v, want %v", p.ESBuild.EntryPoints, want)
+	}
+
+	if p.ESBuild.LogLevel != 3 {
+		t.Fatalf("logLevel = %d, want inherited 3", p.ESBuild.LogLevel)
+	}
+
+	if len(p.Copy) != 1 {
+		t.Fatalf("copy = %d entries, want inherited 1", len(p.Copy))
+	}
+}