Add external diff tool support via INSTA_DIFF_TOOL#844
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max-sixty merged 2 commits intomitsuhiko:masterfrom Dec 14, 2025
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Add external diff tool support via INSTA_DIFF_TOOL#844max-sixty merged 2 commits intomitsuhiko:masterfrom
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I tried it out, this works great for me! Left some other notes though.
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| Environment variables: | ||
| INSTA_DIFF_TOOL External diff tool for displaying diffs (e.g., \"delta --side-by-side\"). | ||
| Invoked as: <tool> [args...] <old_file> <new_file> |
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It would be nice if this was also available as a cli argument.
When the INSTA_DIFF_TOOL environment variable is set (or --diff-tool CLI arg is provided), insta will use the specified tool to display snapshot diffs instead of the built-in diff. The tool supports arguments and is invoked as: <tool> [args...] <old_file> <new_file> Example usage: export INSTA_DIFF_TOOL=delta export INSTA_DIFF_TOOL="delta --side-by-side" cargo insta review --diff-tool difftastic The external tool output is captured and printed through normal channels, so it respects cargo test's output capture (diffs are hidden during `cargo insta test` just like the built-in diff). 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com>
The diff tool option is only useful for `cargo insta review` since `accept` and `reject` don't display diffs - they just apply operations. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com>
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## Summary - Add external diff tool support via `INSTA_DIFF_TOOL` environment variable (#844) - Add `test.disable_nextest_doctest` config option to `insta.yaml` (#842) - Skip non-insta snapshot files in unreferenced detection (#846) - Collect warnings from tests for display after run (#840) - Update TOML serialization to be up-to-date and backwards-compatible (#834) - Support `clippy::needless_raw_strings` lint (#828) ## Test plan - [x] All tests pass - [x] All lints pass 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-authored-by: Claude <noreply@anthropic.com>
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I think a nice solution to #843; would let any diff tool be used, including passing settings to that tool; so that something like side-by-side can work
PR description from Claude follows
When the INSTA_DIFF_TOOL environment variable is set, insta will use the specified tool to display snapshot diffs instead of the built-in diff.
The tool is invoked as: <old_file> <new_file>
Example usage:
export INSTA_DIFF_TOOL=delta
export INSTA_DIFF_TOOL=difftastic
The external tool output is captured and printed through normal channels, so it respects cargo test's output capture (diffs are hidden during
cargo insta testjust like the built-in diff).🤖 Generated with Claude Code