feat(gitlab-sim): 🚀 branches support

internal/cicontext/context.go

@@ -0,0 +1,105 @@
+package cicontext
+
+import "strings"
+
+// Context holds the simulated CI execution environment used for context-aware
+// pipeline evaluation (rules:if:, only:, except:, workflow:rules:).
+// Variables are keyed by their name without the leading $.
+type Context struct {
+	Vars map[string]string
+}
+
+// New builds a Context from high-level shortcut values and optional KEY=VALUE
+// overrides. Predefined CI variables are derived from the shortcuts so callers
+// do not need to know their exact names.
+//
+// Returns an empty Context (IsEmpty() == true) when all inputs are zero values,
+// preserving the existing linting behaviour when no context flags are given.
+//
+// Override priority (highest wins): extraVars > branch/tag/source shortcuts.
+func New(branch, tag, source string, extraVars []string) *Context {
+	if branch == "" && tag == "" && source == "" && len(extraVars) == 0 {
+		return &Context{}
+	}
+
+	vars := make(map[string]string)
+
+	if branch != "" {
+		vars["CI_COMMIT_BRANCH"] = branch
+		vars["CI_COMMIT_REF_NAME"] = branch
+		vars["CI_COMMIT_REF_SLUG"] = slugify(branch)
+		if source == "" {
+			source = "push"
+		}
+	}
+	if tag != "" {
+		vars["CI_COMMIT_TAG"] = tag
+		vars["CI_COMMIT_REF_NAME"] = tag
+		vars["CI_COMMIT_REF_SLUG"] = slugify(tag)
+		delete(vars, "CI_COMMIT_BRANCH") // tag pushes have no branch variable
+		if source == "" {
+			source = "push"
+		}
+	}
+	if source != "" {
+		vars["CI_PIPELINE_SOURCE"] = source
+	}
+	if _, ok := vars["CI_DEFAULT_BRANCH"]; !ok {
+		vars["CI_DEFAULT_BRANCH"] = "main"
+	}
+
+	// KEY=VALUE overrides win over shortcuts.
+	for _, kv := range extraVars {
+		k, v, ok := strings.Cut(kv, "=")
+		if ok {
+			vars[k] = v
+		}
+	}
+
+	return &Context{Vars: vars}
+}
+
+// IsEmpty reports whether no variables have been set (no context flags given).
+func (c *Context) IsEmpty() bool {
+	return c == nil || len(c.Vars) == 0
+}
+
+// Get returns the value of a CI variable (key without the leading $).
+// Returns an empty string when the variable is not defined.
+func (c *Context) Get(key string) string {
+	if c == nil {
+		return ""
+	}
+	return c.Vars[key]
+}
+
+// Summary returns a short human-readable description of the context for CLI output.
+func (c *Context) Summary() string {
+	if c.IsEmpty() {
+		return ""
+	}
+	var parts []string
+	if v := c.Get("CI_COMMIT_TAG"); v != "" {
+		parts = append(parts, "tag="+v)
+	} else if v := c.Get("CI_COMMIT_BRANCH"); v != "" {
+		parts = append(parts, "branch="+v)
+	}
+	if v := c.Get("CI_PIPELINE_SOURCE"); v != "" {
+		parts = append(parts, "source="+v)
+	}
+	return strings.Join(parts, ", ")
+}
+
+// slugify converts a ref name to its GitLab slug form:
+// lowercased, non-alphanumeric characters replaced with '-', leading/trailing '-' removed.
+func slugify(s string) string {
+	var b strings.Builder
+	for _, r := range strings.ToLower(s) {
+		if (r >= 'a' && r <= 'z') || (r >= '0' && r <= '9') {
+			b.WriteRune(r)
+		} else {
+			b.WriteByte('-')
+		}
+	}
+	return strings.Trim(b.String(), "-")
+}