Fix NullPointerExceprion when getGID() was called on null

[LonelyMidoriya]

Summary by CodeRabbit

• Bug Fixes
  • Prevented crashes when processing TrueType fonts with missing or incomplete character mapping data; the renderer now safely falls back to a zero width for unmapped glyphs, avoiding errors for both standard and symbolic mappings.

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[coderabbitai]

Walkthrough

Added null checks for the CmapParser in TrueTypeFontProgram: getWidth and getWidthSymbolic now return 0 when the parser is null; otherwise they obtain a glyph ID from the CmapParser and use getWidthWithCheck(gid).

Changes

Cohort / File(s)	Summary
Null-safety in TrueType font width resolution src/main/java/org/verapdf/pd/font/truetype/TrueTypeFontProgram.java	Added null checks for parser.getCmapParser() in getWidth(int code) and getWidthSymbolic(int code). If CmapParser is null the methods return 0; otherwise they derive glyph ID from the CmapParser and call getWidthWithCheck(gid) to obtain width.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

• Verify both null-check branches correctly handle absent CmapParser and don't alter other code paths.
• Confirm returning 0 is an acceptable fallback for both methods in upstream usage.
• Check for any logging or diagnostics that should accompany the fallback to aid troubleshooting.

Poem

A rabbit nibbles at a missing map,
Hops past nulls with a gentle tap,
If Cmap’s gone and cannot be found,
I return a zero, safe and sound. 🐇✨

Pre-merge checks and finishing touches

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 50.00% which is insufficient. The required threshold is 80.00%.	You can run @coderabbitai generate docstrings to improve docstring coverage.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title directly addresses the main change: adding null checks before calling getGID() on CmapParser to prevent NullPointerException.

✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch null-cmap

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📜 Recent review details

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Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 8a2c1c0 and eb5ab7d.

📒 Files selected for processing (1)

• src/main/java/org/verapdf/pd/font/truetype/TrueTypeFontProgram.java (2 hunks)

🚧 Files skipped from review as they are similar to previous changes (1)

• src/main/java/org/verapdf/pd/font/truetype/TrueTypeFontProgram.java

⏰ Context from checks skipped due to timeout of 90000ms. You can increase the timeout in your CodeRabbit configuration to a maximum of 15 minutes (900000ms). (1)

• GitHub Check: Codacy Static Code Analysis

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[coderabbitai]

Actionable comments posted: 1

Caution

Some comments are outside the diff and can’t be posted inline due to platform limitations.

⚠️ Outside diff range comments (1)

src/main/java/org/verapdf/pd/font/truetype/TrueTypeFontProgram.java (1)

227-228: Apply the same null check here to prevent NPE.

This code has the same NPE risk that was fixed in the getWidth method above. The getCmapParser() call should be null-checked before invoking getGID().

Apply this diff to add consistent null handling:

-        gid = this.parser.getCmapParser().getGID(code);
-        return getWidthWithCheck(gid);
+        if (this.parser.getCmapParser() == null) {
+            return 0;
+        }
+        gid = this.parser.getCmapParser().getGID(code);
+        return getWidthWithCheck(gid);

📜 Review details

Configuration used: CodeRabbit UI

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 6ccfa77 and 8a2c1c0.

📒 Files selected for processing (1)

• src/main/java/org/verapdf/pd/font/truetype/TrueTypeFontProgram.java (1 hunks)

⏰ Context from checks skipped due to timeout of 90000ms. You can increase the timeout in your CodeRabbit configuration to a maximum of 15 minutes (900000ms). (1)

• GitHub Check: Codacy Static Code Analysis