requested changes in envpath

Author: savil

internal/impl/devbox.go

@@ -789,7 +789,7 @@ func (d *Devbox) computeNixEnv(ctx context.Context, usePrintDevEnvCache bool) (m
 
 	debug.Log("current environment PATH is: %s", env["PATH"])
 
-	pathStack := envpath.NewStack(env)
+	pathStack := envpath.Stack(env)
 	debug.Log("Original path stack is: %s", pathStack)
 
 	vaf, err := d.nix.PrintDevEnv(ctx, &nix.PrintDevEnvArgs{
@@ -896,7 +896,7 @@ func (d *Devbox) computeNixEnv(ctx context.Context, usePrintDevEnvCache bool) (m
 	})
 	debug.Log("PATH after filtering with buildInputs (%v) is: %s", buildInputs, nixEnvPath)
 
-	env = pathStack.AddToEnv(env, d.projectDirHash(), nixEnvPath, d.preservePathStack)
+	env = pathStack.PushAndUpdateEnv(env, d.projectDirHash(), nixEnvPath, d.preservePathStack)
 	debug.Log("New path stack is: %s", pathStack)
 
 	debug.Log("computed environment PATH is: %s", env["PATH"])

internal/impl/envpath/pathstack.go

@@ -8,59 +8,64 @@ import (
 )
 
 const (
+	// PathStackEnv stores the string representation of the stack, as a ":" separated list.
+	// Each element in the list is also the key to the env-var that stores the
+	// nixEnvPath for that devbox-project. Except for the last element, which is InitPathEnv.
 	PathStackEnv = "DEVBOX_PATH_STACK"
 
 	// InitPathEnv stores the path prior to any devbox shellenv modifying the environment
 	InitPathEnv = "DEVBOX_INIT_PATH"
 )
 
-// Stack has the following design:
-// 1. The PathStack enables tracking which sub-paths in PATH come from which devbox-project
-// 2. What it stores: The PathStack is an ordered-list of nixEnvPathKeys
-// 3. Each nixEnvPathKey is set as an env-var with the value of the nixEnvPath for that devbox-project.
-// 4. The final PATH is reconstructed by concatenating the env-var values of each nixEnvPathKey env-var.
-// 5. The Stack is stored in its own env-var shared by all devbox-projects in this shell.
-type Stack struct {
+// stack has the following design:
+// 1. The stack enables tracking which sub-paths in PATH come from which devbox-project
+// 2. It is an ordered-list of keys to env-vars that store nixEnvPath values of devbox-projects.
+// 3. The final PATH is reconstructed by concatenating the env-var values of each nixEnvPathKey.
+// 5. The stack is stored in its own env-var PathStackEnv, shared by all devbox-projects in this shell.
+type stack struct {
 
 	// keys holds the stack elements.
 	// Earlier (lower index number) keys get higher priority.
-	// This keeps the string representation of the Stack aligned with the PATH value.
+	// This keeps the string representation of the stack aligned with the PATH value.
 	keys []string
 }
 
-func NewStack(env map[string]string) *Stack {
+func Stack(env map[string]string) *stack {
 	stackEnv, ok := env[PathStackEnv]
 	if !ok {
 		// if path stack is empty, then push the current PATH, which is the
 		// external environment prior to any devbox-shellenv being applied to it.
 		stackEnv = InitPathEnv
 		env[InitPathEnv] = env["PATH"]
 	}
-	return &Stack{
+	return &stack{
 		keys: strings.Split(stackEnv, ":"),
 	}
 }
 
-// String is the value of the Stack stored in its env-var.
-func (s *Stack) String() string {
+// String is the value of the stack stored in its env-var.
+func (s *stack) String() string {
 	return strings.Join(s.keys, ":")
 }
 
-// Key is the element stored in the Stack for a devbox-project. It represents
+// Key is the element stored in the stack for a devbox-project. It represents
 // a pointer to the nixEnvPath value stored in its own env-var, also using this same
 // Key.
 func Key(projectHash string) string {
-	return "DEVBOX_NIX_" + projectHash
+	return "DEVBOX_NIX_ENV_PATH_" + projectHash
 }
 
-// AddToEnv adds the new nixEnvPath for the devbox-project identified by projectHash to the env.
-// It does so by modifying the following env-vars:
+// PushAndUpdateEnv adds the new nixEnvPath for the devbox-project identified by projectHash.
+// The nixEnvPath is pushed to the top of the stack (given highest priority), unless preservePathStack
+// is enabled.
+//
+// It also updated the env by modifying the following env-vars:
 // 1. nixEnvPath key
 // 2. PathStack
 // 3. PATH
 //
 // Returns the modified env map
-func (s *Stack) AddToEnv(
+func (s *stack) PushAndUpdateEnv(
 	env map[string]string,
 	projectHash string,
 	nixEnvPath string,
@@ -81,19 +86,14 @@ func (s *Stack) AddToEnv(
 	}
 	env[PathStackEnv] = s.String()
 
-	// Look up the paths-list for each Stack element, and join them together to get the final PATH.
+	// Look up the paths-list for each stack element, and join them together to get the final PATH.
 	pathLists := lo.Map(s.keys, func(part string, idx int) string { return env[part] })
 	env["PATH"] = JoinPathLists(pathLists...)
 	return env
 }
 
 // Has tests if the stack has the specified key. Refer to the Key function for constructing
 // the appropriate key for any devbox-project.
-func (s *Stack) Has(key string) bool {
-	for _, k := range s.keys {
-		if k == key {
-			return true
-		}
-	}
-	return false
+func (s *stack) Has(key string) bool {
+	return lo.Contains(s.keys, key)
 }

internal/impl/envvars.go

@@ -143,6 +143,6 @@ func (d *Devbox) IsEnvEnabled() bool {
 		parts := strings.Split(keyVal, "=")
 		env[parts[0]] = parts[1]
 	}
-	pathStack := envpath.NewStack(env)
+	pathStack := envpath.Stack(env)
 	return pathStack.Has(envpath.Key(d.projectDirHash()))
 }