Json output by Dragyx · Pull Request #51 · faukah/dix

Dragyx · 2026-01-30T15:44:50Z

Adds an optional feature that allows to output the diffs as JSON instead of printing the normal report.

This PR is still in its early stages and the outputted format is subject to change.

Depends on #50.

Implements #41.

Copilot

Pull request overview

This PR adds an optional JSON output feature to the dix tool, allowing users to get structured output suitable for programmatic processing. The PR also implements a significant refactoring of the store backend to support multiple fallback mechanisms (direct database queries, immutable database access, and command-line tools).

Changes:

Adds JSON serialization support for diff output with serde/serde_json dependencies
Refactors store backend into a trait-based architecture with lazy, eager, and command-based implementations
Introduces new CLI flag --json-output to enable JSON output mode
Adds --force-correctness flag to prefer correctness over performance

Reviewed changes

Copilot reviewed 12 out of 13 changed files in this pull request and generated 10 comments.

Show a summary per file

File	Description
Cargo.toml	Adds serde and serde_json dependencies with optional json feature (enabled by default)
Cargo.lock	Lock file updates for new dependencies
src/version.rs	Adds Serialize derive for Version struct when json feature is enabled
src/store/queries.rs	Extracts SQL queries into constants (refactored from store.rs)
src/store/nix_command.rs	New fallback backend using nix commands for querying store data
src/store/db_lazy.rs	New lazy database connection implementation with streaming results
src/store/db_eager.rs	New eager database connection that collects all results upfront
src/store/db_common.rs	Common database utilities shared between lazy and eager backends
src/store.rs	Major refactoring introducing StoreBackend trait and CombinedStoreBackend for fallback support
src/main.rs	Adds CLI arguments for json-output and force-correctness flags
src/lib.rs	Exposes json module and path_to_canonical_string utility function
src/json.rs	New module implementing JSON serialization and output for diffs
src/diff.rs	Updates to support new backend abstraction and expose helper functions

Comments suppressed due to low confidence (1)

src/main.rs:161

The error message formatting has an unusual line break. The string literal should either be on a single line or use proper multi-line string formatting with backslash continuation or raw strings.

    anyhow!(
      "failed to get closure size due to thread
  error"
    )

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src/store/nix_command.rs

Copilot · 2026-01-30T15:50:52Z

src/store/nix_command.rs

+  let references = Command::new("nix-store").args(args).output();
+
+  let query = references?;


The command execution does not check if the command succeeded (via status code). The code should verify that the command exited successfully before attempting to parse the output. Consider checking the output status and returning an error if the command failed, including stderr in the error message for debugging.

Copilot · 2026-01-30T15:50:53Z

src/json.rs

+pub fn serialize_diffs(diffs: &[Diff]) -> Result<String> {
+  serde_json::to_string(&diffs).map_err(|e| e.into())
+}


The json module lacks test coverage. Given that the repository has comprehensive tests for diff.rs and store.rs, tests should be added for the JSON serialization functionality, including: (1) testing that serialize_diffs produces valid JSON, (2) testing that the JSON structure matches expectations, and (3) verifying that all necessary fields are serialized correctly.

Cargo.toml

src/main.rs

src/json.rs

src/store/db_lazy.rs

src/store.rs

src/store/nix_command.rs

src/store/db_common.rs

Prints the internal Vec<Diff> as json. We might want to fix some format in the future, since the output is currently quite verbose.

src/json.rs

src/main.rs

src/store/nix_command.rs

RGBCube · 2026-02-01T10:29:47Z

Good stuff, mostly some code style nits & better flag naming

Dragyx · 2026-02-08T13:16:47Z

Thanks @RGBCube for having a look at the code!

src/main.rs

RGBCube · 2026-02-09T14:38:00Z

src/store/nix_command.rs

+      let stderr = String::from_utf8_lossy(&cmd_res.stderr);
+      bail!(
+        "nix command exited with non-zero status {}: {}",
+        cmd_res.status,


Prefer keyword arguments here too, foo = foo.bar() and do {foo} in format strings. Do it on all of these, there are others in the diff too.

Dragyx self-assigned this Jan 30, 2026

Copilot AI review requested due to automatic review settings January 30, 2026 15:44

Copilot started reviewing on behalf of Dragyx January 30, 2026 15:45 View session

Copilot AI reviewed Jan 30, 2026

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Dragyx force-pushed the json-output branch 4 times, most recently from 6a8c9fa to 38ce02b Compare January 30, 2026 17:13

faukah force-pushed the json-output branch from 38ce02b to 6e6da79 Compare January 30, 2026 20:41

Dragyx added 2 commits February 1, 2026 00:05

Add initial feature structure

967b958

Add simple json output.

fac01dc

Prints the internal Vec<Diff> as json. We might want to fix some format in the future, since the output is currently quite verbose.

Dragyx force-pushed the json-output branch from 6e6da79 to c44bb08 Compare January 31, 2026 23:07

RGBCube requested changes Feb 1, 2026

View reviewed changes

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src/main.rs Outdated Show resolved Hide resolved

src/store/nix_command.rs Outdated Show resolved Hide resolved

src/store/nix_command.rs Outdated Show resolved Hide resolved

Dragyx added 2 commits February 8, 2026 14:04

Implement some recommendations from copilot

926ef78

Expose store module

94515db

Dragyx force-pushed the json-output branch from c44bb08 to cf3c52e Compare February 8, 2026 13:07

Update readme dix --help output

12531b6

Dragyx force-pushed the json-output branch from cf3c52e to 96851c7 Compare February 8, 2026 13:13

RGBCube approved these changes Feb 9, 2026

View reviewed changes

Change --output-json flag to --output <format>

27dba7a

Dragyx force-pushed the json-output branch from 96851c7 to 27dba7a Compare February 15, 2026 14:09

		let references = Command::new("nix-store").args(args).output();

		let query = references?;

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Dragyx commented Jan 30, 2026

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RGBCube commented Feb 1, 2026

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Dragyx commented Feb 8, 2026

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