fix: Set CHEZMOI_ environment variables for modify_ scripts

pkg/chezmoi/sourcestate.go

@@ -111,6 +111,7 @@ type SourceState struct {
 	readTemplateData        bool
 	userTemplateData        map[string]any
 	priorityTemplateData    map[string]any
+	scriptEnv               []string
 	templateData            map[string]any
 	templateFuncs           template.FuncMap
 	templateOptions         []string
@@ -199,6 +200,13 @@ func WithReadTemplateData(readTemplateData bool) SourceStateOption {
 	}
 }
 
+// WithScriptEnv sets the script environment variables.
+func WithScriptEnv(scriptEnv []string) SourceStateOption {
+	return func(s *SourceState) {
+		s.scriptEnv = scriptEnv
+	}
+}
+
 // WithSourceDir sets the source directory.
 func WithSourceDir(sourceDirAbsPath AbsPath) SourceStateOption {
 	return func(s *SourceState) {
@@ -1673,6 +1681,7 @@ func (s *SourceState) newModifyTargetStateEntryFunc(
 
 			// Run the modifier on the current contents.
 			cmd := interpreter.ExecCommand(tempFile.Name())
+			cmd.Env = s.scriptEnv
 			cmd.Stdin = bytes.NewReader(currentContents)
 			cmd.Stderr = os.Stderr
 			contents, err = chezmoilog.LogCmdOutput(cmd)

pkg/cmd/config.go

@@ -1537,6 +1537,7 @@ func (c *Config) newSourceState(
 		chezmoi.WithLogger(&sourceStateLogger),
 		chezmoi.WithMode(c.Mode),
 		chezmoi.WithPriorityTemplateData(c.Data),
+		chezmoi.WithScriptEnv(c.runEnv),
 		chezmoi.WithSourceDir(c.SourceDirAbsPath),
 		chezmoi.WithSystem(c.sourceSystem),
 		chezmoi.WithTemplateFuncs(c.templateFuncs),

pkg/cmd/testdata/scripts/issue2934.txtar

@@ -0,0 +1,8 @@
+# test that chezmoi sets environment variables for modify_ scripts
+exec chezmoi apply
+grep ^${CHEZMOISOURCEDIR@R}$ $HOME/.modify
+
+-- home/user/.local/share/chezmoi/modify_dot_modify --
+#!/bin/sh
+
+echo ${CHEZMOI_SOURCE_DIR}