fix: sort object names in multi-file dump for deterministic include order (#299)

[tianzhou]

Summary

• pgschema dump --multi-file iterated a Go map (map[string][]diff.Diff) without sorting keys, causing \i include lines in main.sql to appear in random order across runs
• Sort object names alphabetically within each directory group before generating include statements, ensuring deterministic output

Fixes #299

Test plan

• Added TestMultiFileIncludeOrderDeterministic — creates 4 tables + 2 functions, runs FormatMultiFile 20 times, and verifies identical sorted output each time
• Test fails before fix (non-deterministic map iteration detected), passes after
• Full test suite passes (go test ./...)

🤖 Generated with Claude Code

[greptile-apps]

Greptile Summary

Fixed non-deterministic include order in pgschema dump --multi-file by sorting object names alphabetically before generating \i include statements.

• The root cause was Go map iteration order being non-deterministic when iterating map[string][]diff.Diff
• Added sort.Strings() on extracted object names (lines 122-126 in formatter.go) before creating include files
• Test creates 4 tables + 2 functions, runs FormatMultiFile 20 times, and verifies identical sorted output
• Include order now follows: functions/alpha, functions/beta, tables/accounts, tables/orders, tables/products, tables/users (alphabetical within each directory group)

Confidence Score: 5/5

• Safe to merge - simple, well-tested fix for deterministic output
• The fix is minimal (5 lines), solves a well-defined problem, and includes comprehensive test coverage with 20 iterations. The change only affects output ordering, not functionality.
• No files require special attention

Important Files Changed

Filename	Overview
internal/dump/formatter.go	Sorts object names alphabetically before generating include statements to ensure deterministic multi-file output
cmd/dump/multifile_test.go	Adds comprehensive test with 20 iterations to verify deterministic include order for 4 tables and 2 functions

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A[FormatMultiFile called] --> B[Group diffs by directory & object name]
    B --> C[filesByType map created]
    C --> D[Iterate orderedDirs]
    D --> E{objects exist for directory?}
    E -->|No| D
    E -->|Yes| F[Extract object names from map]
    F --> G[Sort object names alphabetically]
    G --> H[Iterate sorted names]
    H --> I[Write object file]
    I --> J[Add include statement]
    J --> K{More objects?}
    K -->|Yes| H
    K -->|No| L{More directories?}
    L -->|Yes| D
    L -->|No| M[Write main.sql with sorted includes]
    M --> N[Return success]
    
    style G fill:#90EE90
    style F fill:#FFB6C1

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_{Last reviewed commit: 586030a}

[Copilot]

Pull request overview

This PR fixes non-deterministic output in pgschema dump --multi-file caused by random Go map iteration order when generating include statements in main.sql.

Changes:

• Sort object names alphabetically within each directory group before generating \i include lines in multi-file dumps
• Add comprehensive test that verifies deterministic output across 20 runs with multiple tables and functions

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
internal/dump/formatter.go	Extract map keys to slice, sort alphabetically, then iterate sorted slice to generate deterministic include statements
cmd/dump/multifile_test.go	Add TestMultiFileIncludeOrderDeterministic to verify consistent sorted output across multiple runs

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