fix: normalize function argument types to prevent spurious replacements

[p-c-h-b]

This fixes a bug where function signature comparison would incorrectly treat functions as different when PostgreSQL stores parameter types with schema qualifications while the source SQL uses unqualified names.

Problem

When PostgreSQL stores a function, it may qualify custom type names with their schema (e.g., public.user_status). However, source SQL often uses unqualified type names (e.g., user_status).

When pgschema compares the old and new function signatures:

1. Old function (from database): my_func(public.user_status)
2. New function (from SQL files): my_func(user_status)

pgschema would treat these as different functions and attempt to:

DROP FUNCTION my_func(public.user_status);
CREATE OR REPLACE FUNCTION my_func(user_status) ...;

The DROP would fail if other objects (views, triggers, other functions) referenced my_func, even though CREATE OR REPLACE would have worked fine.

Solution

Added signature normalization in ir/ir.go:

1. New helper function stripSchemaPrefixFromType(typeName, schema) that removes schema prefixes from type names when they match the function's own schema:

   • Handles quoted schema qualifications: "public".user_status → user_status
   • Handles unquoted qualifications: public.user_status → user_status
   • Preserves cross-schema references: other_schema.type → other_schema.type

2. Modified Function.GetArguments() to normalize all parameter types before building the signature string used for comparison.

This ensures that public.user_status and user_status are treated as identical when comparing function signatures, allowing CREATE OR REPLACE to work instead of attempting a DROP.

Changes

• Added stripSchemaPrefixFromType() helper function
• Modified Function.GetArguments() to apply normalization to all parameter types

Fixes #155 (partially - this is the third of three fixes mentioned in the issue)

[Copilot]

Pull Request Overview

This PR adds schema prefix normalization for function parameter types to ensure stable function identification across PostgreSQL schema-qualified type names. The main purpose is to strip matching schema prefixes from parameter types when building function argument strings.

• Added stripSchemaPrefixFromType helper function to normalize schema-qualified type names
• Modified GetArguments method to use the new normalization function
• Applied consistent formatting to struct field alignments and removed extraneous blank lines

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[Copilot]

Pull Request Overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated no new comments.

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[tianzhou]

@p-c-h-b I developed a new fix and added test case in #160. So closing this one.

Thanks for reporting and taking the initiative.