Module parser 

.env file parser — merged implementation.

Combines the correctness of the original parser (typed errors, key validation, circular-expansion detection, depth limiting) with the feature set of the refactored parser (backtick quotes, multiline values, bare $VAR expansion, inline-comment stripping, configurable value trimming, and a proper Default impl).

Format support

Feature	Supported
KEY=value	✓
export KEY=value	✓
# comments	✓
Inline # comments	✓ (opt-in via ParserConfig::allow_inline_comments)
Double-quoted values	✓
Single-quoted values	✓
Backtick-quoted values	✓
Multiline values	✓ (opt-in via ParserConfig::allow_multiline)
${VAR} expansion	✓
$VAR expansion	✓
Circular expansion guard	✓
Strict uppercase keys	✓ (opt-in via ParserConfig::strict)

Compatibility with other modules

Every call site in the codebase uses one of these three patterns:

// Pattern A — most common (all commands)
let parser = Parser::default();
let env_file = parser.parse_file(".env")?;
env_file.vars  // HashMap<String, String>

// Pattern B — config override (validate --strict, tests)
let parser = Parser::new(ParserConfig { strict: true, ..Default::default() });

// Pattern C — parse from string (tests, template command)
let vars = parser.parse_content("KEY=value")?;

This merged parser satisfies all three patterns without any call-site changes. See § Compatibility notes below for per-module details.

Error handling

All errors are ParseError variants. Because the commands wrap parser calls with anyhow::Context (.with_context(|| ...)), the structured error converts automatically into anyhow::Error at the boundary — no changes needed in any command file.

Compatibility notes by module

Module	Method used	Breaking change?
commands/validate.rs	parse_file(&str)	None — signature preserved
commands/diff.rs	parse_file(&str)	None
commands/scan.rs	parse_file(&str)	None
commands/convert.rs	parse_file(&str)	None
commands/sync.rs	parse_file(&str)	None
commands/template.rs	parse_file(&str)	None
commands/migrate.rs	parse_file(&str)	None
commands/backup.rs	Not used directly	N/A
commands/doctor.rs	parse_file(&str)	None
commands/init.rs	parse_file(&str)	None
core/converter.rs	EnvFile.vars	None — field name preserved
Tests	parse_content	None — method name preserved

Structs

EnvFile

The result of parsing a .env file or string.

Parser

.env file parser.

ParserConfig

Controls parser behaviour. Construct with Default::default() and override individual fields as needed.

Enums

ParseError

Structured parse errors with line numbers and context.

Type Aliases

ParseResult

Convenience alias used throughout the parser internals.