Bug 119095 – Web Inspector: fix inconsistent use of 0-based and 1-based line numbers

• Status: RESOLVED
• Resolution: FIXED
• Component: Web Inspector

[Brian Burg]

Throughout the backend there are ugly and confusing mixes of 0-based an 1-based line numbers. I propose standardizing on 0-based line numbers, and only changing the ordinal base (to 1-based) at the very outer layer of the frontend. This is mostly how things work now, but there are unnecessary exceptions.

Some particularly troublesome spots:

 * ScriptDebugServer - This whole file is a rat nest. It's not documented whether 0-based or 1-based line numbers are used to index breakpoints per-line. hasBreakpoint() is scary and manually changes ordinal bases.

 * Timeline event line numbers are 1-based in the inspector protocol.

 * ConsoleMessage stack trace line numbers are 1-based.

Chime in if there are more places to fix.

Fixing:

 * If line numbers must be used as keys, then use an OrdinalNumber instead of 0- or 1-based line numbers.

[Radar WebKit Bug Importer]

<rdar://problem/14549211>

[Brian Burg]

To clarify, JSC has standardized on 1-based lines and columns; I was proposing to standardize what the inspector uses, but not necessarily what JSC does.

For things like ScriptDebugServer, I think it makes sense to correct or introduce uses of OrdinalNumber, and document places where separate line/col fields are necessary.

[Joseph Pecoraro]

Speaking of this, it looks like ScriptDebugServer had a bug after JSC changed to 1 based column #s:
<https://webkit.org/b/120334> Web Inspector: Column Breakpoint not working, may be off by 1

[Brian Burg]

This was fixed in recent refactorings of the backend.