Add 'View DFG' command, similar to 'View CFG'

[asgerf]

Adds a View DFG command alongside the View CFG command:

It behaves the exact same way as View CFG, except the tag it uses to identify the CodeQL query ends with print-dfg instead of print-cfg. (For context, DFG stands for data flow graph, and CFG stands for control flow graph)

[Copilot]

Pull request overview

Adds a new “View DFG” command to the CodeQL VS Code extension, implemented to mirror the existing “View CFG” workflow but selecting a different contextual-query tag (print-dfg).

Changes:

• Generalize the CFG template provider into a graph template provider parameterized by KeyType (CFG vs DFG).
• Add PrintDfgQuery key type and tag/name mappings for contextual query resolution.
• Register new VS Code commands/menu contributions for “View DFG” and wire them into extension activation.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
extensions/ql-vscode/src/language-support/contextual/template-provider.ts	Renames/generalizes CFG provider into a graph provider supporting CFG/DFG via injected KeyType/display name.
extensions/ql-vscode/src/language-support/contextual/key-type.ts	Adds PrintDfgQuery and maps it to ide-contextual-queries/print-dfg.
extensions/ql-vscode/src/language-support/ast-viewer/ast-cfg-commands.ts	Refactors CFG execution into a reusable viewGraph helper and adds DFG command handlers.
extensions/ql-vscode/src/extension.ts	Instantiates CFG + DFG graph providers and registers the new commands.
extensions/ql-vscode/src/common/commands.ts	Extends AstCfgCommands type with the new DFG command IDs.
extensions/ql-vscode/package.json	Adds codeQL.viewDfg* commands and menu/command-palette contributions (canary-gated).

Comments suppressed due to low confidence (1)

extensions/ql-vscode/src/language-support/contextual/template-provider.ts:355

• These error messages report tag ${this.keyType}, but this.keyType is the enum value (e.g. PrintDfgQuery), not the actual CodeQL query tag string. Consider using tagOfKeyType(this.keyType) (or otherwise including the resolved tag, like ide-contextual-queries/print-dfg) so the guidance is actionable.

Also, "exacly" is misspelled (should be "exactly").

        `Found multiple Print ${this.displayName} queries. Can't continue. Make sure there is exacly one query with the tag ${this.keyType}`,
      );

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[Copilot]

Same issue here as above: the message uses tag ${this.keyType} (enum value) rather than the actual tag string used for lookup. Using tagOfKeyType(this.keyType) would make the error actionable, and "exacly" should be corrected to "exactly".

This issue also appears on line 354 of the same file.